Lakewood- Colorado′s mountain snowpack suffered significant declines during the month of March. According to data from the latest snowpack measurements, conducted by the USDA-Natural Resources Conservation Service (NRCS), the state′s snowpack decreased in terms of percent of average in all basins of the state during March. These decreases were enough to lower snowpack percentages to below average totals for this date across the most of the state, with the only exception being the northwestern portion of Colorado. The statewide snowpack decreased to 96 percent of average on April 1. This is the first statewide snowpack reading of this season to be below average, according to Allen Green, State Conservationist, with the NRCS. Back on January 1, the statewide snowpack was 120 percent of average; an indication of just how dry the last few months have been.
The lowest snowpack percentages were measured in both the South Platte, and the combined San Juan, Animas, Dolores, and San Miguel basins, at only 86 percent of average. While the South Platte basin has been hovering just slightly below average most of this season, the southwestern basins were reading 135 percent of average last January after a bountiful December.
This year′s below average snowpack on April 1 adds to the series of drier than average years. Below average snowpack readings have been measured on April 1 in 10 of the last 12 years in Colorado. In addition, the April 1st snowpack reading is the most critical for the state′s water managers.
With snowpack totals nearing their seasonal maximum accumulations on this date, these readings are the best indication of what the state can expect for most of its yearly runoff and water supplies.
Forecasts for expected runoff across Colorado have declined each month as the state′s snowpack percentages have steadily declined. With the latest snowpack data, runoff forecasts for spring and summer water supplies have decreased to below average across most of the state. Only those streams and rivers in the Colorado, White, and Yampa basins of northwestern Colorado are expected to flow at slightly above average volumes this year. For water users across southern Colorado the latest runoff forecasts are showing the greatest decline from early-winter, when the outlook was very positive. "This summer′s runoff in some of those basins has decreased to only 75 to 85 percent of average", said Green.
While summer runoff may be below average for much of the state this summer, reservoir storage remains just slightly above average statewide. All basins are storing at least near average volumes for this time of year, with the exception of the Rio Grande basin.