Here’s the release from the NRCS (Brian Domonkos):
Snow accumulations during the month of February generally favored Northern Colorado. Mountain precipitation ranged from a high of 153 percent of average in the combined Yampa-White-North Platte river basin to a low of 60 percent of average in the Rio Grande. NRCS Hydrologist Karl Wetlaufer notes, “While February snow accumulations did improve the snowpack in many parts of the state, snowpack still remains below normal levels in all major basins except the Rio Grande”. Snowpack ranges from a low of 80 percent of median in the combined San Miguel-Dolores-Animas-San Juan basin to a high of 101 percent in the Rio Grande.
Similar to recent precipitation patterns, reservoir storage is currently more plentiful in the northern half of Colorado. Currently the only river basins in the state holding above average reservoir storage are the Colorado and combined Yampa-White river basins. On the low end, the combined San Miguel-Dolores-Animas-San Juan and the Rio Grande river basins have 60 and 67 percent of average reservoir storage, respectively.
As has been the case throughout this winter, a major consideration when it comes to spring runoff is a drought that was well in place as the snowpack began to accumulate. The summer and fall of 2020 was exceptionally warm and dry prior to the start of water year 2021. NRCS Hydrologist Wetlaufer continued to comment that “This led to dry soil moisture conditions and the expectation is that snowmelt runoff will produce lower volumes than would commonly be observed with a similar snowpack”.
The lowest streamflow forecasts in the state are coming out of the Southern San Juan Mountains and the Gunnison River Basin. The average of forecasts in these basins is for 54 and 57 percent of average volumes, respectively. The highest streamflow forecasts in the state are in the South Platte, with the average of forecasts being for 80 percent of average streamflow volumes.