Most Major Basins in Colorado Holding Above Normal Snowpack as Spring Nears

• Link to Colorado Water Supply Outlook Report for March

Denver, CO – March 9th, 2023 – While the month of February didn’t quite bring the statewide precipitation values of the previous month, snowpack remains above to well above normal in all major basins expect the Arkansas. Basins west of the Continental Divide are fairing particularly well with respect to snowpack, with all basins that comprise the greater Colorado River watershed holding at least 120 percent of median snowpack. The South Platte and Rio Grande River basins are holding closer to, but still above normal snowpack. NRCS hydrologist Karl Wetlaufer comments “To put some of the higher snowpack numbers in a different perspective, several basins in Western Colorado have already well exceeded normal peak values with about a month left in the usual accumulation season. This is an encouraging place to be from a water supply standpoint for these portions of the state that have had several years of below normal streamflow runoff.”

Streamflow forecasts also vary widely across Colorado largely driven by differences in current snowpack and total accumulated precipitation since October 1st 2022. This year in particular streamflow forecasts are spread over a large range, with respect to normal, even within the same major basins. Wetlaufer explains “It is important to explore the specific streamflow forecasts that interest you in addition to the basin-wide average of forecasts. Regional differences in snowpack and precipitation this year have left notable discrepancies between forecasts within the same major basins.” The upper main stem South Platte and southern sub-basins of the Arkansas are examples of rivers forecasted to have well below normal streamflow volumes in contrast to more plentiful forecasts further north in their respective basins.

Reservoir storage is always a key component of the water supply picture in Colorado and across the West. This year in Colorado there have yet to be significant changes in how storage values are distributed across the state and they remain a reflection of hydroclimatic conditions of the past several years. “The good news this year is that many of the basins which have had low streamflow volumes for the last several years, depleting reservoir storage, are forecasted to have above normal April-July runoff volumes. This includes the Gunnison and the combined San Miguel-Dolores-Animas-San Juan River basins” concludes Wetlaufer. While peak snowpack is approaching, much can change over the coming months so it is advisable to continue closely monitoring for changing conditions.

^{* San Miguel-Dolores-Animas-San Juan River basin}

For more details see the March 1^st Water Supply Outlook Report.