Aided by a significant series of storms starting after Christmas and continuing into the New Year most major basins in the state are now holding well above normal amounts of snow water equivalent (SWE) for this time of year. Currently only the Arkansas and Rio Grande River basins have a below normal snowpack. In other basins across the state snowpack ranges from 112 percent of normal in the South Platte to 154 percent in the combined Yampa, White, and Little Snake River basins.
Natural Resources Conservation Services Hydrologist Karl Wetlaufer notes that, “While there are still several months of snow accumulation season to come, for most of the state this is certainly an encouraging place to be in early January from a water supply standpoint.” So far this winter the Sangre de Cristo Mountains in south-central Colorado, which feed water into portions of both the Rio Grande and Arkansas basins, have had the least luck with respect to accumulating significant amounts of snowfall.
Streamflow forecasts across Colorado follow similar spatial trends to the current snowpack. The most plentiful streamflow forecasts are currently in the North Platte and combined Yampa, White, and Little Snake River basins. Forecasts in these basins are for 135 percent of normal streamflow volumes for the April-July runoff period. On the low end of the spectrum are streamflow forecasts for rivers flowing out of the Sangre de Cristo Mountains into the eastern Rio Grande and southern Arkansas River basins, where the least snow has accumulated this water year. Streamflow forecasts in this region call for between 54 and 76 percent of normal streamflow volumes. Many parts of the state continued receiving significant snowfall into the first few days of January not incorporated in forecasts.
Reservoir storage remains highly variable across the major basins of Colorado. Plagued by consecutive years of low streamflows and impacted by withdrawals to supplement storage in Lake Powell, currently the Gunnison and the combined San Miguel-Dolores-Animas-San Juan River basins have the two lowest reservoir storage amounts in the state, both near 65 percent of normal. On the high end, the Colorado Headwaters and Rio Grande River basins are holding slightly above normal reservoir storage volumes. Hydrologist Karl Wetlaufer continued, “Additionally soils have retained more moisture going into this winter compared to previous years thanks to ample summer precipitation. This has the potential to substantially improve the efficiency of snowmelt transitioning to observed streamflow compared to previous years.
Special to the Herald Times
