Southwest Snowpack

A string of storms in early to mid-December brought substantial snow to portions of the Southwest, especially in central and southern Arizona and New Mexico. One month ago, nearly all of the basins reported above-average snowpacks. Since the beginning of 2012, however, storms have been few and far between, causing the amount of water contained in snowpacks, or snow water equivalent (SWE), to decline. As of January 16, SWE measured by snow telemetry (SNOTEL) stations ranged from 74 percent of average in the Verde River Basin to 110 percent of average in both the Upper Salt and Upper Gila river basins (Figure 8). SWE in New Mexico had a larger range, from 62 percent of average in the Animas River Basin to 177 percent in the Mimbres River Basin.

December storms that dropped copious precipitation on the Southwest did not  pack the same punch in Colorado, Wyoming, and Utah—states that supply most of the water to the Colorado River and Rio Grande—as much. In addition, dry conditions have reigned in these regions and in the Southwest during the last few weeks. As a result, SWE values were predominantly below average across the Upper Colorado River Basin as of January 16. For example, SWE in all of the basins in Colorado measured less than 83 percent of average, and some stations in Utah reported values as low as 37 percent of average, with 10 of 14 basins reporting less than 60 percent of average. These conditions are contributing to below-average spring streamflow forecasts for the Colorado River.

Seasonal precipitation and temperature outlooks issued by the NOAA-Climate Prediction Center (CPC) show increased chances for above-average temperatures and below-average precipitation across Arizona and New Mexico (see Figures 9 and 10). These forecasts reflect expected impacts of the current weak to moderate La Niña event.