Click on the thumbnail graphic for the snowpack map by basins. There is an ugly red splat over the upper South Platte River.
Click here to download a copy. Here’s an excerpt:
January brought cold temperatures and little moisture to Colorado until the very last week when a significant snow storm hit most of the state. Areas near Steamboat Springs and Durango received upwards of 18 inches during the last week of the January, yet due to the dry start to the month, statewide snowpack ended up being only marginally better than the previous month. Increased snowpack percentages across southwestern Colorado were offset by significant decreases in the northeastern basins and all major basins remain below normal for this time of year. Consecutive months of below average snowpack accumulation are statistically decreasing the possibility of reaching normal conditions by April. Last year’s below average snowpack did not offer any buffer to our current situation. Currently, reservoir storage volumes across the state are at 69 percent of average and 66 percent of last year’s storage. The February 1 streamflow forecasts reflect the below average snowpack conditions throughout the state. The San Miguel, Animas, Dolores and San Juan basins are the only areas in the state where forecasts for April to July runoff volumes improved this month. Water users in all basins should start planning for below average surface water supplies this season. The potential for shortages this season is great.
Snowfall across Colorado was nearly nonexistent for most of January. During this time snowpack percentages were decreasing daily as the gap between current conditions and long-term normals widened. The situation began to improve during late January when storm systems brought much needed moisture to the state. The storms were not enough to tip the scales to normal, but they did help halt the downward slide. Statewide snowpack was at 72 percent of normal as of February 1. The basins that benefited the most from these storms were the basins in the southwest region of the state. The snowpack in the Upper Rio Grande basin increased from from 65 percent of normal on January 1 to 78 percent of normal on February 1. The combined San Miguel, Dolores, Animas and San Juan basins jumped 18 percentage points in January; from 70 percent of normal to 88 percent of normal on February 1. The Arkansas and Gunnison River basins each showed a nominal increase in snowpack percentage compared to last month. The remaining basins in the state showed an overall decline in the percent of normal from what was reported on January 1. The South Platte basin had the largest departure from last month’s report. The snowpack in this basin dropped 13 percentage points this past month, declining from 67 percent of normal on January 1 to just 54 percent of normal February 1.
Precipitation across the state during the month of January was 83 percent of average. Statewide totals were influenced by above average monthly totals recorded in the Upper Rio Grande and the combined basins of the San Miguel, San Juan, Dolores and Animas Rivers. During January the Upper Rio Grande basin received precipitation that was 107 percent of average for this time of year and precipitation in the southwest basins was 120 percent of average. The Gunnison basin came in at 90 percent of average for the month. The remaining basins received between 69 and 72 percent of average precipitation during January with the exception of the South Platte Basin. The South Platte basin recorded just 50 percent of the average precipitation for the month. Year to date precipitation for the state remains below average for this time of year; as of February 1 total precipitation was just 72 percent of average.
Due to last winter’s poor snowpack, reservoir storage volumes continue to track below average levels. At the end of January reservoirs within the state were storing 2,311,000 acre feet of water. At this same time in 2012, reservoirs in the state held 3,606,000 acre feet. Below average storage volumes were reported at the end of January in the Arkansas, Gunnison, Colorado, South Platte, Upper Rio Grande and the combined San Juan, Animas, Dolores, and San Miguel basins. The greatest departure from average was in the Upper Rio Grande basin which reported its reservoirs volumes at just 51 percent of average. The Yampa and White River basins reported reservoir storage to be 103 percent of average and 85 percent of last year’s storage. The storage in the Yampa and White basins may currently be above average, but these basins have the smallest reservoir capacity in the state.
Streamflow forecasts across the state reflect the below normal snowpack conditions measured on February 1. Forecasts for all points across Colorado are calling for below normal seasonal streamflow volumes this spring and summer. The lowest forecasts, as a percent of normal, occur in the Arkansas and South Platte basins. Forecasts in these basins are less than 65 percent of normal and as low as 45 percent of normal for the April to July time period. Forecasts for the Colorado, Gunnison, and Yampa and White basins have declined from those issued last month; expected streamflow volumes in these basins generally range from 50 to 70 percent of normal. As a result of the large snowfall amounts received in January, current runoff forecasts in the Upper Rio Grande and the combined San Juan, Animas, Dolores and San Miguel basins have improved somewhat from last month’s predictions. It is important to note that at this point in the season the mountains have typically accumulated 60 percent of their annual snowpack in Colorado. The potential for recovering to normal conditions at this point in the season is not promising, but it is possible if we see exemplary spring conditions.