Radiometer near Mancos used to forecast cloud-seeding potential

April 5, 2014
Calibrating the radiometer via The Durango Herald

Calibrating the radiometer via The Durango Herald

From The Durango Herald (Mary Shinn):

On Monday meteorologist, Marta Nelson, installed a temporary radiometer at Jackson Lake near the Mancos Water Conservancy District. The instrument is able to determine the best combination of water content in clouds and temperature to use a cloud-seeding generator.

Cloud-seeding generators throw up silver iodide into the atmosphere to harvest the extra water because snow will form around it.

“We can see relative humidity and vapor and the potential for a cloud to form. We can also see inside a cloud that’s already formed, so if we’re looking for liquid water versus ice that is frozen in the cloud the radiometer can tell the difference and help tell the cloud-seeding people when to run the generators or when it’s not going to do any good,” she said. Nelson works for Radiometrics Corp., based in Boulder, which installs similar machines all over the world.

The new data also will help scientists decide if the local cloud-seeding generator at Spring Creek should be run later into the winter season, said Jeff Tilley, director of weather modification at the Desert Research Institute in Reno. The institute operates the local cloud-seeding generator remotely. The data collected over the next month will be applied to operations next winter because the Spring Creek generator is almost out of cloud-seeding solution, he said.

The institute is collaborating with the Colorado Water Conservation Board on the project, and the board is paying the $8,500 to lease the radiometer for a month.

Across the state, about $1 million is spent on cloud seeding, and about 65 percent of the funds are provided by local entities such as ski areas, water districts and towns. The other 35 percent of the funds are provided by state and other funding.

The generator near Mancos has been in place for about five years, and in that time, there has been some benefit in the area, Tilley said.

“The impression we have is that we have seen some difference,” he said.

Cloud seeding is safe because silver iodide won’t break down in any way that’s harmful, Nelson said.

More cloud-seeding coverage here. More San Juan River Basin coverage here.

Ski areas, et. al, kick off this winter’s cloud-seeding program

October 17, 2013
Cloud-seeding graphic via Science Matters

Cloud-seeding graphic via Science Matters

From the Colorado Independent (Bob Berwyn):

In Colorado, ski-area operators and water managers have been known to do a few rain dances and — privately at least — pray to their own God when drought strikes. But in the age of technology and hubris, when nearly every challenge is met with engineering, they aren’t just waiting for Mother Nature to put her cards on the table. Instead, there’s a growing interest in seeding clouds with silver iodide to coax every possible bit of moisture from passing storms.

Weather modification has historic roots in the Cold War era, when both the U.S. and Soviets looked at ways to weaponize weather, and more recently, U.S. intelligence agencies decided to help fund a far-reaching study aimed at determining if there’s a way to mitigate global warming with technology and engineering.

Proponents have claimed for years that seeding can increase snowfall in targeted areas by as much as 15 percent. As a result, water providers like Denver Water, and big ski resorts, including Vail, Breckenridge and Winter Park, are all helping fund a $1 million cloud-seeding program in Colorado’s north-central mountains, hoping to improve ski conditions, as well as boost stream flows and reservoir storage.

Recent news about record-low flows from Lake Powell, the key Colorado River reservoir, has spurred even more interest in enhancing natural precipitation, said one of the state officials who manages what’s formally called a weather modification program. A roster of companies involved in cloud seeding and related activities shows that weather modification is a growth industry.

The state program is run by the Colorado Water Conservation Board, which issues permits and sets basic rules — for example cloud-seeding stops when the snowpack reaches a certain level to address concerns about avalanches and flooding.

But those rules haven’t quelled concerns, as there are still a few people left who probably think that tinkering with the weather on a large scale is probably one of the worst ideas ever. Those sentiments were reflected during a hearing for cloud seeding permits in the early 2000s. Residents of Evergreen turned up en masse to claim that, ever since Vail started seeding clouds (way back in the 1980s), snowfall in their town has declined.

The CWCB program was jump-started with state seed money in the early 1970s, but since then has become 80 percent – 90 percent self-funded through grants and participation by resorts and water providers, with everyone seeing cloud-seeding as a low-cost alternative to building new reservoirs and pipelines. And with an uncertain outlook for Colorado River flows, even downstream states like Arizona and California are ponying up to help pay for cloud seeding in the headwaters.

The question about downwind impacts seems reasonable. After all, there’s only so much moisture in every cloud. But weather experts like Colorado state climatologist Nolan Doesken say there’s not a shred of evidence to show that cloud-seeding affects snow and rainfall downwind of the specific target areas. The weather pattern most suitable for mountain cloud seeding (a steady, moisture-laden jet stream out of the northwest) generally leave the plains high and dry.

On the other hand, Doesken said there’s no clear evidence to show that seeding enhances snowfall anywhere near the amount claimed.

“If it really increased snowfall by 15 percent, you’d be able to see that in streamflow records from, say, the Gunnison Basin (where seeding has been ongoing for many years), but that’s not the case,” Doesken said. Overall, he believes that seeding does boost precipitation, but by a lesser amount than claimed…

So when your score your first face shots this coming winter, go ahead and enjoy the celebratory bonfire in honor of Ullr, the Norse god of skiing. But just to be on the safe side, don’t forget to raise your glass in a toast the men and women who promise better living — including more snow — through chemistry and engineering.

More cloud-seeding coverage here and here.

Cloud-seeding program for the central mountains for this season ended on April 10 #COdrought #ColoradoRiver

May 1, 2013


From the Summit County Citizens Voice (Bob Berwyn):

While the winter’s biggest snow totals came after the end of this year’s program, the seeding operations may have helped bring near-average snowfall to area in February and March, according to the operators, who are now measuring their efforts under a “target and control” evaluation that will be submitted to the Colorado Water Conservation Board for review.

Durango-based Western Weather Consultants, which seeds the central mountains, was able to extend operations into early April and use all its allotted operational days, said Larry Hjermstad. During the 2012-2013 season, the central mountains program cost $293,600 and targeted an area of about 1,668 square miles of the Upper Colorado River Basin, generally above elevation 8,500 feet, in parts of Pitkin, Eagle, Summit, and Grand counties. Front Range water providers and ski areas, along with other partners, help fund the program, aimed at enhancing water supplies and boosting ski conditions at A-Basin, Breckenridge, Keystone and Winter Park, all included in the target area…

In past seasons, Hjermstad estimated that cloud-seeding may have boosted snowfall by as much as 15 percent in targeted areas.

Cloud-seeding efforts in Colorado have a long, on-and-off history dating back to the 1970s, when the federal Bureau of Reclamation was active in the southwestern mountains, said state climatologist Nolan Doesken, who acknowledged that there is still a debate about the effectiveness of cloud-seeding. Doesken said that there is good evidence that cloud-seeding can work in the right conditions, with very specific requirements as to wind direction, moisture and temperatures. Outside that range, the results are less clear.

Funding comes from the Front Range Water Council including Aurora Water, Denver Water, Colorado Springs Utilities, Northern Colorado Water Conservancy District, Twin Lakes Reservoir & Canal Company, Southeastern Colorado Water Conservancy District, and Pueblo Board of Water Works. The Colorado River Water Conservation District, A-Basin, Keystone, Breckenridge, and Winter Park also participate.

The Colorado Water Conservation Board and the Lower Basin States, including the Southern Nevada Water Authority, Central Arizona Water Conservation District, and California Six Agency Committee also help fund the cloud-seeding, but don’t directly participate in the program, said program manager Maria Pastore, of Glenwood Springs-based Grand River Consulting.

More cloud-seeding coverage here and here.

Grand Mesa cloud-seeding program history and results #ColoradoRiver

April 9, 2013


From the Grand Junction Free Press (Sharon Sullivan):

For 50 years, humans have attempted to modify the weather for the purpose of increasing snowpack, to fill up reservoirs, reduce hail, and even prevent rain. The scientific practice of cloud seeding has been utilized on Grand Mesa since the 1990s. Two years ago, the Water Enhancement Authority stepped up its Grand Mesa program by doubling the number of cloud seeders to 16. “We’re trying to increase snowpack on the Mesa, to fill up the reservoirs,” said Mark Ritterbush, the Grand Junction water operations supervisor and secretary for the Water Enhancement Authority (WEA).

The WEA is comprised of the City of Grand Junction, Powderhorn Ski Mountain Resort, Collbran, the Grand Mesa Water Conservancy District, and Overland Ditch and Reservoir Company. Funding for the cloud-seeding program comes from those entities, as well as Delta County, the Colorado River District, the Colorado Water Conservation Board and lower Colorado River basin states.

Meteorologists determine where to place the cloud-seeding machines on the Mesa. Oftentimes, they’re located on private property where landowners are paid rent to host the machines.

In China, cloud seeders — many of them farmers — are paid to use anti-aircraft guns and rocket launchers to release pellets containing silver iodide into clouds, according to Wikipedia. Other areas disperse the precipitation-enhancing agents via airplanes.

On the Grand Mesa, cloud-seeding machines consist of tanks on the ground filled with a silver-iodide solution containing chemicals such as acetone. The solution is sprayed across a propane-fueled flame, causing the particles to drift with the wind current up into the cloud. The condensation nuclei turn into ice crystals, ride along with the cloud and fall out as a snowflake. Silver iodide is used because its crystalline structure is almost identical to ice, Ritterbush said.

“A meteorologist (John Thompson of Montrose) watches storms as they come in,” Ritterbush said. “He calls and tells (the landowners) when to turn it on. Rarely are all 16 cloud seeders running at the same time.”


There is an ongoing debate regarding the effectiveness of cloud seeding versus letting nature take its course, Ritterbush said. Ten years ago, the National Academies of Science released a report saying, that after 30 years of research, there is no convincing proof of intentional weather modification efforts. “In nature, it’s hard to set up an experiment with a control,” Ritterbush said. “It’s a conundrum how to compare.”

Yet, studies suggest cloud seeding can increase snowpack 5 to 15 percent, which makes the program’s annual cost of between $30,000 and $40,000 cost-effective when you factor in the extra water, Ritterbush said. The cost variable is due to weather conditions, how often seeding takes place, and the cost of silver, Ritterbush said. According to the World Meteorological Policy Statement, “a well-designed, well-executed program shows demonstrative results,” said Joe Busto, who runs the weather modification permitting program out of Denver for the Colorado Water Conservation Board.

The Grand Mesa has been a forum to introduce new equipment and different seeding technologies, Busto said. The topography is ideal for setting up cloud-seeding machines at a high elevation, he said. “There’s a rich history of research on the Grand Mesa, during the ’70s, ’80s, and ’90s,” Busto added.

Arlen Huggins, a semi-retired research scientist with the Desert Research Institute in Reno, Nev., is familiar with the Grand Mesa project. Huggins said there is plenty of convincing evidence that modifying weather is effective for increasing precipitation. He mentioned prior Bureau of Reclamation studies, plus a recently completed five-year experiment in Australia. “There’s a lot of evidence related to snowfall enhancement,” Huggins said. “It makes it a viable option for increasing water supply.”

The Water Enhancement Authority is in the process of collecting data comparing seeded areas versus non-seeded areas on the Mesa, Ritterbush said.


So, what happens when silver-iodide particles hit the ground or land in lakes or rivers? While there has been no monitoring for silver in western Colorado’s environment, researchers in Australia have spent millions searching for traces of the mineral, Ritterbush said. In Australia, where lake beds and soils have been tested, they “just don’t find it near toxic levels,” Busto said.

Huggins, who is considered a cloud-seeding expert, said he’s often asked about potential risks of silver toxicity in the environment. “It’s a minuscule amount of silver being released,” Huggins said. “The silver iodide amounts released are not harmful. (The particles) are not soluble in water. It cannot be taken up by aquatic species. It does not bio-accumulate.”

There are approximately 106 cloud-seeding sites in Colorado, including Summit County, Gunnison, Telluride and the Dolores area, the West and Eastern San Juan mountains. Vail and Beaver Creek have the oldest program, having cloud-seeded for 38 years. Most permits are issued from November through March and sometimes into mid-April, Busto said. “We monitor snowpack, avalanche hazards, and suspend programs when needed,” he said.

A 2010 statement from the American Meteorological Society states that “unintended consequences of cloud-seeding, such as changes in precipitation or other environmental impacts downwind of a target area have not been clearly demonstrated, but neither can they be ruled out. Continued effort is needed toward improved understanding of the risks and benefits of planned modification through well-designed and well-supported research programs.”

More cloud-seeding coverage here and here.

Cloud-seeding rules may help to determine the efficacy of the various delivery methods #CORiver

December 8, 2012


From the Summit County Citizens Voice (Bob Berwyn):

As part of the state-authorized weather modification plan, operators of cloud-seeding operations are required to complete annual “target versus control” analyses, comparing snowfall in target areas against similar non-targeted control areas. Over time, the data from those evaluations may help determine if cloud seeding really does boost snowfall by up to 15 percent, as claimed by the operators.

“This method is credible and develops relationships between snow data and tracks precipitation totals over time in both seeded areas and non-seeded areas to help track the efficacy of the program,” said Maria Pastore, of Glenwood Springs-based Grand River Consulting, who manages the central mountains cloud-seeding rogram.

“In addition, the State has new data types and evaluation methods suggested for cloud seeding programs,” Pastore said. “They are not required but are suggested as good periodic evaluations that can help the long-term sustainability of these programs.”

Cloud seeding in Colorado involves burning silver iodide in ground-based generators to inject tiny particles of the material into approaching weather systems. The silver iodide is said to provide nucleii for crystal formation and growth, helping to wring a bit of additional moisture from the clouds.

For the 2012-2013 season, the central mountains program will cost $293,600 and target an area of about 1,668 square miles of the Upper Colorado River Basin, generally above elevation 8,500 feet, in parts of Pitkin, Eagle, Summit, and Grand counties. If it works, the program could benefit A-Basin, Breckenridge, Keystone and Winter Park, all included in the target area.

More cloud-seeding coverage here and here.

Drought news: Public hearing tonight for Western Weather Consultants’ cloud-seeding application

September 24, 2012


Here’s the notice from the CWCB website:

The CWCB has received an application from Western Weather Consultants to renew their permit for a wintertime ground based cloud seeding program on behalf of Denver Water and Colorado Springs Utilities and several other sponsors.

This notice of intent has been advertised in eighteen newspapers in eighteen counties for this public hearing.

The public hearing will be held at La Quinta Inn & Suites, Loveland Room, 560 Silverthorne Lane, Silverthorne, Colorado, at 6:00 PM on Monday September 24, 2012.

The public record will be held open so that comments can be emailed to or mailed with postmark of October 1, 2012 for consideration as part of the record of decision.

Public comments oral and written are used by the State to develop a record of decision that is used to deny, approve, or approve with special terms and conditions a weather modification permit.

More CWCB coverage here.

Gunnison County files application to continue cloud seeding program for another ten years

September 7, 2012


From The Chaffee County Times (Casey Kelly):

North American Weather Consultants has filed an application with the Colorado Water Conservation Board for a 10-year renewal of its cloud seeding program in Gunnison. According to the group, Chaffee County could benefit from additional water from the program.

Since 1950, NAWC has been conducting weather modification programs in the western United States and has been cloud seeding in the Gunnison area for the past 10 years. The purpose of the operation is to increase precipitation and snowpack in the area for agriculture, municipal water, recreation and tourism.

Current cloud seeding programs in Colorado:

Central Colorado Rocky Mountains Program (Denver Water and Winter Park)
Upper Roaring Fork Basin Program (Colorado Springs Utilities)
Vail/Beaver Creek Program (Vail/Beaver Creek Ski Areas)
Gunnison River Basin Program (Gunnison County, Upper Gunnison River WCD)
Grand Mesa (Water Enhancement Authority which is comprised of Collbran WCD, Fruitland Mesa WCD, Crawford WCD, Grand Mesa Pool)
Western San Juan Mountains Program (Southwestern WCD, City of Durango, Animas La Plata WCD, Durango Mountain Resort, Dolores WCD)
Eastern San Juan Mountains Program (Pagosa Area Water and Sanitation District, San Juan WCD, Southwestern WCD)

More cloud seeding coverage here and here.

Cloud seeding: Applied science or alchemy?

August 9, 2012


From the High Country News’ Goat blog (Emily Guerin):

Making rain may seem a bit like alchemy, but the practice has been around since the 1940s, when engineers at General Electric began experimenting with dumping dry ice into clouds from airplanes. Water districts and ski resorts around the West got into the practice in the 1970s, shooting silver iodide into winter clouds from mountain-top cannons…

Silver iodide crystals behave like ice, attracting water droplets to them until they grow big enough to fall to the ground as snow. Cloud seeding advocates say the practice is inexpensive—$10-20 per acre-foot of water created—and can boost snowfall by 10 to 15 percent. They’re also quick to point out there are no documented negative environmental effects of the process.

But it’s hard to separate cloud seeding-induced precipitation from what falls naturally from the sky. A 2010 study by Israeli researchers examining rainfall patterns and cloud seeding over the Sea of Galilee in Northern Israel found that a series of cyclones were responsible for increased rainfall over a six-year period, not cloud seeding. The state of Wyoming is currently spending $11 million on a multi-year study to determine whether the practice works and is cost-effective. Results are expected in 2014.

Still, the science is apparently convincing enough for water districts in Southern California, Nevada and Arizona to pay Upper Colorado River Basin states to seed clouds. Since 2006, Lower Basin states have spent over $800,000 in Colorado and around $500,000 in Utah and Wyoming.

More cloud seeding coverage here and here.

Delta County chips in some dough for the Grand Mesa cloud-seeding effort this year

January 3, 2012


From the Delta County Independent (Hank Lohmeyer):

A multi-agency supported cloud seeding project on the Grand Mesa is in line to receive $1,000 in support from the Delta County Commissioners next year [2012]…

The multi-agency Water Enhancement Authority “is a non-profit organization of three water conservancy organizations,” explained WEA secretary treasurer Mark Ritterbush in a letter to the commissioners. The three agencies are the Grand Mesa Water Conservancy District, the Grand Mesa Water Users Association, and the Collbran Water Conservancy District. The three districts, along with other regional government bodies, donate to the Water Enhancement Authority.

According to Ritterbush’s letter to the BoCC, “Research conducted in the San Juan Mountains concluded that cloud seeding may increase snowpack levels by an additional 5 to 15 percent. The extra water realized through cloud seeding was produced at a cost of $0.94 to $1.15 per acre foot. Silver iodide is used to seed the clouds.”[...]

According to a map that accompanies the request letter, the WEA has 12 cloud seeding generators on Grand Mesa.

More cloud-seeding coverage here.

Colorado River Basin: What are the reasonable water management options and strategies that will provide water for people, but also maintain a healthy river system?

December 25, 2011


Here’s a guest commentary written by Eric Kuhn, David Modeer and Fred Krupp running in The Denver Post. The trio are issuing a call to arms of sort, asking for input for the Colorado River Basin Study. Here’s an excerpt:

Management of the Colorado River is a complex balancing act between the diverse interests of United States and Mexico, tribes, the seven basin states, individual water users, stakeholders, and communities. The challenges posed by new growth and climate change may dwarf anything we faced in the past. Instead of staring into the abyss, the water users, agencies, and stakeholder groups that make managing the Colorado River responsibly their business are working together, using the best science available to define the problem, and looking for solutions.

We’re calling our inquiry the Colorado River Basin Study, and we want your help. As Colorado River management professionals, we have a lot of knowledge and ideas, but we know that we don’t have them all. We want ideas from the public, from you, but we need your input by February 1. You can submit your suggestions by completing the online form at:

The big question we need to answer is: What are the reasonable water management options and strategies that will provide water for people, but also maintain a healthy river system? We don’t believe there’s a single silver bullet that will resolve all of our challenges. We want to continue to explore the benefits and costs of every possibility, from conservation to desalination to importing water from other regions.

The West was built on innovation and hard work, and that spirit is still strong. Our landscapes and communities are unparalleled in their beauty, resilience, and character. The economic well-being of our rural and urban communities in the Colorado River basin is inextricably linked to Colorado River and its environmental health.

That’s why we are asking for the public’s input to help us craft a study showing a path forward that supplies our communities with the water they need to thrive and protects the health of the Colorado River-and the ecosystems and economies it supports.

More Colorado River basin coverage here.

Cloud-seeding: Gunnison County, Mt. Crested Butte, CWCB and the Upper Gunnison River Water Conservancy District ink a deal with North American Weather Consultants for the 2011-2012 season

November 21, 2011


From The Crested Butte News (Alissa Johnson):

In spite of early concerns that funding for cloud seeding might dry up, Gunnison County entered into an operational agreement with North American Weather Consultants for the 2011-2012 winter season on November 15. With the total bill projected at $95,000, a 3.26 percent increase over last year, the Upper Gunnison River Water Conservancy District came through with a $26,500 contribution. The county will contribute $10,000 and Mt. Crested Butte budgeted $3,000. The Colorado Water Conservation Board will cover $47,500 in matching funds, and the remaining moneys will be collected from a variety of local contributors.

More cloud-seeding coverage here and here.

Western Weather Consultants report that their cloud-seeding efforts increased Summit County snowfall by 12 to 22 inches last winter

November 2, 2011


From the Summit County Citizens Voice (Bob Berwyn):

This year, the $274,000 central Colorado mountains program includes seven Front Range water providers and four ski areas: Arapahoe Basin, Keystone, Winter Park and Breckenridge, all contributing to the cost of the cloud-seeding program, according Joe Busto, head of the state’s weather modification program. The CWCB supports the program with grant funding…

The report estimates that last winter’s cloud-seeding between early November and early February resulted in an additional 12 inches of snow at Breckenridge, 16 inches at Keystone and 22 inches at Arapahoe Basin…

To avoid unwanted consequences such as excessive flooding, cloud-seeding operations stop when certain snowpack thresholds are reached, or if avalanche hazards rise to a critical level. For example, seeding operations in Summit County were suspended last winter during a pre-Christmas storm because of the high snowpack in the area.

Here’s the link to the report. More cloud-seeding coverage here and here.

The Lower Arkansas Water Conservancy District heard a pitch for a potential cloud-seeding program at their last meeting

October 23, 2011


From The Pueblo Chieftain (Chris Woodka):

Cloud-seeding, using silver iodide crystals fired from ground cannons, is already widely used in Colorado. Mainly using for increased snowpack in the mountains, the cannons are also used for hail suppression in some areas like the San Luis Valley. There are 111 generators in the state, said Joe Busto, who coordinates cloud-seeding for the Colorado Water Conservation Board. Programs have continued for decades and in the last six years, the state and cooperating agencies have spent $3.9 million for cloud-seeding programs…

Just over the state line, Kansas has been conducted summer cloud seeding to suppress hail and increase rainfall since 1975, said Walt Geiger, meteorologist for the Kansas program. He explained the Kansas program to the Lower Arkansas Valley Water Conservancy District last week, and suggested a similar approach could help Eastern Colorado…

Airplanes fly both into and below thunderstorms, using dry ice (frozen carbon dioxide) and silver iodide both to reduce the size of hail and increase rainfall. Updrafts allow silver iodide crystals to flow into the clouds from below. Dry ice is released into the clouds by planes flying near the edges of storms…

The theory behind cloud-seeding is that it increases precipitation by injecting trillions of nuclei into clouds. That encourages more rain or snow, and reduces the size of hail by creating more targets for loose droplets to cling to in the clouds. Large hailstones gain size as droplets attach to them as they move through clouds. Airplanes are are used on the plains because ground cannons are not effective in reaching the zone where hail forms — about 11,000-16,000 feet above ground, where there are freezing temperatures, even in summer. Above that zone, ice crystals don’t precipitate as easily.

More cloud-seeding coverage here and here.

Cloudseeding update

February 28, 2011

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From (Dann Cianca):

George Stowell lives in Gunnison and is the operator of one of the many cloud seeding generators in the county. The generator is actually located in his back yard and works by injecting the cloud seeding solution into a propane burner. The heat carries the particulate that results into the upper levels of the atmosphere where the particles act, in simple terms, as an attractive place for tiny water vapor droplets to gather. Could seeding works by increasing the efficiency by which rain drops or ice crystals form within the cloud. Atmospheric conditions have to be just right for this to work, however, so the generator is typically only turned on a few times per season. The state issues permits through the Colorado Water Conservation Board and these permits only allow the operators to seed at when the permit area will be affected. This basically happens when the wind is blowing a certain way.

The Gunnison County program has been ongoing for about ten years and is partially sponsored by the county itself. The county isn’t actually the largest source of funding for the program however as many other interests which include agriculture groups, municipal water districts and even ski resorts contribute…

Operators of these programs say that the science is sound and that it provides good results. With Colorado’s dependency on water, they say that having extra snow-pack can make a huge difference on the economy of the state. That is why these programs have expanded over the years to include many areas of Western Colorado. Generators exist in the San Juans, the Upper Gunnison River Basin, the Grand Mesa area and even near Vail to name a few.

More cloud seeding coverage here and here.

2011 Colorado legislation: The Senate Agriculture and Natural Resources Committee votes 4-3 to continue weather modification licenses

January 21, 2011

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From The Durango Herald (Joe Hanel):

On Thursday, state senators recommended the government continue to offer weather-modification licenses for at least another nine years…

The Senate Agriculture and Natural Resources Committee voted 4-3 to go forward with a bill that continues the licensing program. Without action by the Legislature this year, the state would stop offering licenses…

Only eight entities do cloud-seeding in Colorado, and three are in Southwest Colorado. The city of Durango and water districts around Bayfield and Pagosa Springs run one program, the Animas-La Plata and Dolores water districts cooperate with Durango Mountain Resort on another, and a third centers on Telluride ski area.

More cloud-seeding coverage here and here.

New study questions the effectiveness of cloud seeding

November 4, 2010

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From Science Daily:

…research now reveals that the common practice of cloud seeding with materials such as silver iodide and frozen carbon dioxide may not be as effective as it had been hoped. In the most comprehensive reassessment of the effects of cloud seeding over the past fifty years, new findings from Prof. Pinhas Alpert, Prof. Zev Levin and Dr. Noam Halfon of Tel Aviv University’s Department of Geophysics and Planetary Sciences have dispelled the notion that seeding is an effective mechanism for precipitation enhancement.

The findings were recently reported in Atmospheric Research…

During the course of his study, Prof. Alpert and his colleagues looked over fifty years’ worth of data on cloud seeding, with an emphasis on the effects of seeding on rainfall amounts in a target area over the Sea of Galilee in the north of Israel. The research team used a comprehensive rainfall database and compared statistics from periods of seeding and non-seeding, as well as the amounts of precipitation in adjacent non-seeded areas. “By comparing rainfall statistics with periods of seeding, we were able to show that increments of rainfall happened by chance,” says Prof. Alpert. “For the first time, we were able to explain the increases in rainfall through changing weather patterns” instead of the use of cloud seeding.

More cloud seeding coverage here and here.

Cloud-seeding update

April 4, 2010

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From The Durango Telegraph (Allen Best):

A half-century after cloud-seeding began in the West, it continues to be regarded by many as something akin to chicken-noodle soup for colds. Or, on the more sinister side, snake oil. But water authorities in thirsty states of the American Southwest have no such doubts. For several winters, they have been increasing their budgets for seeding clouds passing over the mountains of Colorado, where about half of the total volume in the Colorado River originates. “We’re believers down here,” says Tom Ryan, resource specialist with the Metropolitan Water District of Southwestern California. “The lower-basin folks believe it works. We believe that the science is adequate to move forward.”

While still relatively small, just $152,000 this winter, the money from lower-basin states has more than tripled since 2006. The money has been used to spew silver iodide particles into clouds over the San Juan Mountains, the Gunnison Basin, and Grand Mesa, all regions with ski areas. The states also contributed to renewed seeding operations at Winter Park in partnership with ski-area operator Intrawest. Vail Resorts also continued its seeding operation for Vail and Beaver Creek, a program that began in 1978. It’s Colorado’s longest-continuous seeding operation.

More cloud-seeding coverage here and here.

Cloud seeding update

December 11, 2009

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Here’s a look at cloud seeding efforts worldwide from the Associated Press via The New York Times. From the article:

Faced with water shortages, growing populations and the threat that climate change could make matters worse, governments around the globe have increasingly turned to cloud seeding in an attempt to wring more rain and snow from the sky. But the efforts are threatened by budget cuts in states struggling to begin an economic recovery and by critics who insist the technique is unproven and might pose a threat to the environment. ”When there is a drought in a particular country, they start looking at alternative sources of freshwater, and cloudy air is one source,” said Duncan Axisa, a scientist at the National Center for Atmospheric Research in Boulder, Colo., who supports expanding cloud-seeding research.

Government agencies and utilities from California to North Dakota spend an estimated $15 million a year on cloud seeding, and the number of projects has jumped by nearly a third in the last decade. But spending in the United States is far lower than in many other countries. China spends an estimated $100 million a year on cloud-seeding efforts that include using anti-aircraft guns and rocket launchers to blast the sky with silver iodide. ”What’s going on in the U.S. is tiny,” said Arlen Huggins, an associate research scientist at the Desert Research Institute in Reno, Nev. ”There’s more being done outside the U.S. than here.” Other countries conducting cloud-seeding research include Australia, France, Greece, Saudi Arabia, Turkey and Venezuela.

In the U.S., utilities that run hydroelectric dams are among the most active cloud seeders. They say it is a cost-effective way to increase limited water supplies by 10 percent or more. Cloud seeding is also used in Texas and the Midwest to make hail smaller, reducing crop damage…

Colorado has doubled its state and local spending on cloud seeding over the last 10 years to about $700,000 a year. In 2005, Wyoming lawmakers committed nearly $9 million to a five-year project to determine whether the technology works. Cloud-seeding supporters say federal research funding would not only validate the system but lead to improvements in techniques. ”We want to chip away at changes in climate change now and do a good job at augmenting our precipitation now,” said Joe Busto, who sits on the North American Interstate Weather Modification Council, a group of regulators from 10 states organized to promote cloud seeding.

More cloud seeding coverage here and here.

Denver Water and Winter Park Resort to pony up $110,000 for cloud-seeding

September 23, 2009

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From the Sky-Hi Daily News (Tonya Bina):

[Winter Park] and Denver Water are sharing the $110,000 cost of the project, which will take place in locations within 35 miles of the ski area. Denver Water last partook in cloud seeding over Winter Park in 2002-2003 and 2003-2004. The project is slated to take place during the months of November, December and January, according to Steve Schmitzer, manager of water resource analysis for Denver Water.

Meanwhile, a supporting $60,000 cloud-seeding project will take place from November through March in the same area coordinated by the Colorado Water Conservation Board and water users from the lower Colorado River basin states of Arizona, California and Nevada…

About 10 Winter Park-Denver Water financed generators will be located on mostly private properties, and will be turned on and off depending on weather conditions and the presence of moisture-producing clouds. The two other generators will be located in higher areas and managed remotely by computer. The project involves a meteorologist who will determine appropriate times for cloud seeding. The quantities of iodide present in runoff due to cloud seeding equates to less iodine that what is found in salt on food, according to report on cloud seeding during the 2008 Arizona Weather Modification Conference. There is also more silver exposure found in tooth fillings, and there have been no human effects from cloud seeding found in 40 years of research, the report reads.

More cloud seeding coverage here and here.

Southwestern Colorado: Local cloud seeding projects

March 15, 2009

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Here’s a background piece on cloud seeding in southwestern Colorado from Kristen Plank writing for the Cortez Journal. She has written a nice primer on the subject also. From the article:

[Larry] Hjermstad, founder of Western Weather Consultants LLC, seeds locally for approximately 10 different entities that support the cloud seeding program, from the town of Telluride to the Dolores Water Conservancy District.

The DWCD invests in two of Hjermstad’s cloud seeding programs in hopes to increase inflow into McPhee Reservoir. Mike Preston, manager for the DWCD, said the water district has played a part in the program since 2000, and paid approximately $17,000 for the 2008-2009 winter program. “Ski areas are investing in the program for the snow to ski on, but our interest is pure and simple,” Preston said. “If we can increase the inflows into the McPhee Reservoir by some percentage, then everyone benefits.”[...]

Hjermstad recounted an independent study done by Bernard Silverman, prior chief scientist with the U.S. Bureau of Reclamation, that showed the effects of a 33-year cloud seeding program on Vail’s surrounding streams. The study, lasting from 1977 to 2005, showed an eight to 30 percent increase in stream flows. “(Silverman) wasn’t looking at snow as being of value, but rather water as being of value,” Hjermstad said. “The study verified that precipitation increases are reflected in stream flow increases. To me, this is the missing ‘ground link’ for what we are trying to do with precipitation.”[...]

Cloud seeding, or weather modification practices, is a popular process throughout the world. Locally, a total of 34 “ice nuclei” generators are spread across the San Juan Mountains, working from November through the end of March. Hjermstad will have operators turn on generators for roughly 24 storms during a three-month period.

Well over a trillion seemingly invisible silver iodide nuclei will work their way into the bottom portion of a cloud system, where they will attract moisture, produce snowflakes and fall to earth. The compound works so well at producing additional snowfall because of its nearly identical characteristics to an ice crystal. It’s as safe as one, too, Hjermstad said. “One reason silver iodide was chosen was because, as a molecule, it is extremely tightly held together once the two elements combine,” he said. “Nothing in nature breaks it apart.” This includes the sun, the photosynthetic process in plants, or anything from the digestive systems of humans, animals or aquatic wildlife. Hjermstad said that cloud seeding programs also do not take away from any precipitation that may have been dispersed into towns downwind.

More Coyote Gulch coverage here and here.

Four years of Wyoming cloud-seeding efforts

February 15, 2009

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Here’s an update on Wyoming’s 5 year cloud-seeding project, from Wes Smalling writing for the Casper Star Tribune. From the article:

[Bruce] Boe is one of several scientists working on the five-year Wyoming Weather Modification Pilot Project, an $8.8 million research program funded by the state of Wyoming. The project’s scientists, along with state water managers, hope to find proof of whether the decades-old practice of seeding clouds — trying to squeeze more precipitation out of passing storms — actually works and that it’s a practical option for increasing the state’s water supply. Members of the world’s science community — cloud-seeing advocates and skeptics alike — are watching the project closely. “For a scientist doing research, this is it. As far as in terms of the research, it is the biggest in the United States by far,” Boe said…

The Wyoming project is in its fourth year, only the second winter in which cloud seeding in earnest has actually been performed. The first two years involved mostly taking measurements and weather readings, obtaining permits from the U.S. Forest Service, gathering other statistical data and getting equipment in place…

While Boe’s company is contracted to perform the cloud-seeding operations, independent teams of scientists from the Colorado-based National Center for Atmospheric Research and the Desert Research Institute in Nevada are independently evaluating whether any increases in precipitation that occur are from cloud seeding or from just normal variations in the weather. That’s the real trick to proving if it works. Cloud-seeding scientists estimate that, if done properly, pumping silver iodide into a cloud will increase snowfall in most cases by about 10 to 15 percent. That’s roughly the same percentage of natural variability possible in normal weather patterns…

It’s too early to say with any certainty that Wyoming’s cloud seeding is working to make more snow, but the scientists are beginning to amass a massive amount of vital information from the project. They still have much more data to collect. They conducted 26 four-hour seeding events in southern Wyoming last winter and more than 30 this winter. Ideally, they would like to have more than 200 cases to examine by the end of the five-year project…

While clouds are often seeded from airplanes, the seeding on the Wyoming project this winter is all being done from the ground by generators on 20-foot towers. Inside a generator placed upwind, a propane flame heats the silver iodide solution, and a nozzle sprays it into the air. It rises into the cloud and is carried by the wind to a target area, which is where the scientists want it to snow. There are eight generators in each mountain range, the Snowies and the Medicine Bows, and another seeding site on the west side of the Wind River Range that has 10 generators.

Meteorologists determine when conditions are right for seeding and tell the technicians which generators to turn on. The technicians, sitting many miles away at computers, activate the generators remotely through satellite modems. Boe, using a machine in his cabin called an acoustic ice nucleus counter, checks the outside air during seeding operations to detect the presence of silver iodide to make sure the particles are reaching the target area…

Before, during and after seeding events, the weather is monitored closely. Independent evaluation teams from NCAR and DRI check the snow for the presence of silver iodide and to collect other statistical data. Seed generators are never turned on at the same time in both the Snowy Range and Medicine Bow Mountains — only randomly either in one mountain range or the other. The forecasters and evaluators are not told which mountain range was seeded, which should eliminate any bias in their predictions and conclusions, said Dan Breed, lead scientist for NCAR. Seeding only one range at a time also allows researchers to collect a double dose of data from each storm — one from a seeded mountain range and one that only received natural snowfall. Comparing results between the two ranges could help determine if increases in snow were a result of seeding or that ever-elusive variability that occurs with natural snowfall…

Periodically this winter, [University of Wyoming] professor Bart Geerts and graduate students will fly over snowstorms in a Kingair research aircraft as cloud-seeding experiments are going on to study how the clouds are affected. Using technologies called cloud radar and LINAR, short for Light Detection and Ranging, the crew will take snapshots of the clouds similar to the three-dimensional slices of a medical MRI scan. “We are basically trying to look at it in the finest detail in time and space. We’re actually looking at the cloud as it is injected with silver iodide,” Geerts said. When a cloud is seeded, “The idea is that silver iodide injected into a cloud is going to turn all that liquid water into ice pretty quickly. We want to see if that really happens.”[...]

University of Tennessee professor Glen Tootle is leading a study on the effects of an increased snowpack on spring and summer runoff. The university experiment could determine what a small snowpack increase in the Medicine Bow Mountains would mean for the North Platte River drainage. No one knows for sure if 10 percent more snow created from cloud seeding would necessarily produce 10 percent more water for the state’s supply. “Those basic questions have not been answered,” Geerts said.

More Coyote Gulch coverage here.


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