Persistent rainy, snowy skies altering many regions of the SW for the better this winter
An atmospheric river is bringing heavy rain and mountain snow to #California. Check out the conveyor belt of clouds and moisture heading toward the West Coast in this loop from our newly operational #GOES17 (#GOESWest) satellite. Learn more: https://t.co/DhXRshmtyJ pic.twitter.com/fix8G2myrO
— NOAA Satellites (@NOAASatellites) February 13, 2019
Improving drought conditions (and there is a lot of that going on in the Southwest as of late), never occur universally.
Yes, snowpack in California’s Sierra Nevada – an important source of southern California’s water supply – recently stood at 129 percent of average. And that was before the enormous mid-February “atmospheric river” began pounding the entire Golden State.
As reported by the federal Natural Resources Conservation Service, meanwhile, those same storms battering the West Coast this winter have had a strong effect on moisture in the Colorado River Basin.
As of February 14, the Service’s SNOTEL sites above Lake Powell were reporting total precipitation averaging 108 percent of normal thus far in this snowpack season.
Closer to home, Arizona’s Salt and Verde rivers watershed has “experienced many productive storm systems that have left behind an Average Watershed Precipitation Accumulation” at 118 percent of normal for the current water year (as of mid-February), according to Salt River Project’s Surface Water Resources division.
The same big mid-February storms traversing California will likely produce substantial watershed accumulation in this state as well.
Between rainfall and snowpack build-up in the higher elevations of Arizona’s eastern mountains, the storms “will likely lead to significant responses on the tributaries of both the Verde and Salt Rivers and ultimately increased inflow to both Horseshoe and Roosevelt reservoirs,” reported Charlie Ester, manager of Surface Water Resources.
For a watershed that last year experienced some of the driest conditions in recorded history, this winter’s storms are proving invaluable.
Still, drought gives ground reluctantly.
As of February 14, the U.S. Drought Monitor was reporting that 84 percent of Arizona remained under “abnormally dry” conditions. While the worst of the worst drought conditions – those regions designated as experiencing “exceptional drought” – have been banished from Arizona for now, the Four Corners region of the state is still experiencing “extreme drought,” the second-worst drought designation.
(“Exceptional Drought” conditions continue to plague northwest New Mexico, particularly the areas surrounding Farmington, N.M.)
The feel-good story of Arizona’s winter moisture-producing season, though, appears to be that of the C.C. Cragin Reservoir, a 15,000 acre-foot reservoir operated by SRP near Payson that had dropped so low last summer that the company decided not to pump any water from it.
Shutting down the Cragin reservoir had proved to be a strong body-blow to Payson residents, who had counted on the promise of 3,000 acre-feet of water from the highly dependable facility beginning in 2018. As recently as the end of last summer’s monsoon season, the Cragin reservoir was no more than 20 percent full.
Decent, if intermittent, moisture earlier this winter pushed reservoir levels to 46 percent by early February. Then, the really big storms began hitting Arizona’s Mogollon Rim country.
Between February 3 and February 6, the reservoir rose nearly ten feet per day. As of February 13, Cragin water levels had risen to within about 89 percent of capacity, according to the U.S. Geological Survey’s National Water Information System.