Arizona has officially started the new year with no snow, leaving the state dry — even for a drought. Winter storm systems usually bring snowfall to the mountain watersheds by Thanksgiving, with basin snow packs reaching maximum capacity in March. As the snow melts, the runoff replenishes reservoirs and fills streams and rivers in the springtime.
The Arizona Basin Outlook Report released by USDA's Natural Resources Conservation Service (NRCS) shows zeros instead of numbers indicating inches of water from snowfall measured at 38 sites throughout the state. The federal agency monitors snow conditions in Arizona's mountain watersheds each winter to estimate the amount of water available for spring and summer uses.
Larry Martinez, water supply specialist with the NRCS in Phoenix, said it is unusual for Arizona not to have a snow pack by now. “Even the Bright Angel snow course on the north rim of the Grand Canyon National Park was bare Jan. 1. It was 1990 since that last occurred and 1990 was a relatively dry year,” he said.
“Arizona's stream flow forecasts closely mirror the state's dismal snow pack readings. As a result, water users can expect reduced runoff this season,” Martinez said. These volumes range from 30 percent to 48 percent of the 30-year median for the Salt, Verde, San Francisco, Gila, and Little Colorado Rivers.
“To make matters worse, we are beginning the new year with a moisture deficit in the high country,” he said. Data collected at NRCS mountain snow telemetry (SNOTEL) stations show that seasonal precipitation for Oct. 1 through Dec. 31 ranged from 21 percent to 37 percent of average, which is about one-third the amount for this time of year. Martinez explained that because the mountain soil moisture is short, any snowmelt will first be absorbed into the soil instead of becoming stream flow this spring.
This is bad news for water users in the rural areas of the state who depend on melting snow to sustain reservoir storage and fill irrigation systems. “Many growers of pasture and hayland in rural areas may not be able to raise as much crop as in normal years. When your water supply fails to materialize because of poor snow packs in the mountains, there's a definite effect on a farmers' ability to grow crops and a rancher's ability to raise livestock,” Martinez said.
According to the National Weather Service, the outlook for precipitation this year is not encouraging. Climate prediction experts indicate warmer-than-average temperatures through June and below-average precipitation through March.
“Last year was a very wet winter, which prevented a potentially disastrous year for ranchers, farmers, recreationists, wildlife, and fire,” Martinez said.
“At this point, only a dramatic and sustained shift in the weather will improve the outlook for snow in Arizona,” Martinez said. “If this dry condition persists much longer into the snow season, it will be difficult to catch up.”