Southwest Snowpack

Where snow has fallen in the high country it has melted. As of November 18, the snowpack conditions in Arizona and New Mexico were exhibiting less-than-average snow water equivalent (SWE) in most basins, according to the Natural Resources Conservation Service’s (NRCS) snow telemetry (SNOTEL) monitoring stations (Figure 8). The average SWE for Arizona is approximately 20 percent of the 1971–2000 average. The San Francisco River Basin reports the lowest SWE values in the state, with approximately 5 percent of average.

In New Mexico, most basins have reported less than 42 percent of average. SWE in the Mimbres River Basin, however, is more than 600 percent of average because 0.3 inches of SWE have fallen; the historical average is only 0.1 inches.

The Rocky Mountain states to the north, which supply most of the water in the Colorado River and Rio Grande, have experienced near-average early winter snowfall. The NOAA–Climate Prediction Center’s winter outlook for December–February shows a greater chance for above-average temperatures and below-average precipitation for many parts of Arizona, New Mexico, Utah, and Colorado through the winter and early spring. These forecasts are based on the current moderate to strong La Niña event. These events tend to bring drier and warmer-than-average conditions to the region.