The drought’s getting worse and the reservoirs are drying up.
Best get used to it, say a growing number of climate prediction models.
The whole of the southwest remains in the grip of a severe drought. In Arizona, that means a failed monsoon season followed by a so-far dry fall. Much of Arizona set records on both fronts this year.
The predicted storms this week did little to cushion the blow of a bone-dry year, with water experts predicting more water rationing next year together with a dangerous fire season.
The plentiful groundwater in the White Mountains and Payson’s completion of the C.C. Cragin pipeline will provide the region with a water supply cushion most of the rest of the state lacks.
However, SRP this year will empty the C.C. Cragin Reservoir, which means that if the reservoir doesn’t fill with winter runoff, the East Verde River could end up going dry in the spring and Payson may not get its 3,000 acre-foot allotment, just two years after completing the $54-million pipeline.
Normally, Payson gets about 5 inches of rain in September, October and November. This year we’ve had just a couple of weak storms. Normally, Payson gets another two inches in December – but we’ve gotten only a trace so far.
Show Low normally gets about 4.5 inches in September through November and 1.5 inches in December. But so far the area’s gotten only a handful of not very productive storms. The average temperature in Show Low in November is 57 degrees, with an average low of 30 degrees. This year the high temperature averaged about 61 degrees in November.
The same holds true across the region. Hopi, dry-farmed corn crops have withered in the midst of perhaps the longest, toughest drought in 1,000 years. Navajo families have been hauling water in the pandemic, not just for cattle and sheep but for homes.
Roosevelt Lake’s still 81% full, but the inflow to the giant reservoir on the Salt and Verde Rivers remains at about half the normal level.
The same thing’s happening on the chain of Colorado River reservoirs that supply about 40% of Arizona’s water supply. The region had a relatively normal winter in 2019-2020. However, the drought-parched watersheds soaked up much of that water and then above-normal temperatures and a hot, dry spring further reduced runoff. As a result, Lake Powell and Lake Mead have gotten half their normal runoff. This could trigger a reduction in the release of water from Lake Powell, which would force the rationing of water from Lake Mead, which is down to less than 40%.
Unfortunately, the sea-surface cooling in the Eastern Pacific has intensified – increasing the odds of a warm, dry winter in Arizona. The trend has added Texas to areas of the U.S. suffering from severe or exceptional drought, which already included almost all of Arizona.
“Drought persistence is favored for the southern portions of the Western Region,” concluded the National Weather Service, “with drought expansion possible across southern California. Above-normal temperatures favored for December-February may exacerbate the drought conditions by keeping mountain snow levels abnormally high.”
In October, “severe to extreme” drought gripped 23% of the U.S., including all of Apache, Navajo and Gila counties. That rose from 18% in September.
The high temperatures and severe drought this year contributed to the record-breaking wildfires in California, Oregon, Washington and Colorado. Another dry, hot winter could produce a dangerous wildfire season in the spring in Arizona.
The National Weather Service concluded, “Several states had a top 10 dry October and record dry August-October and May-October, with Utah ranking driest on record for January-October. The excessive heat from California to the Four Corners states broke records and exacerbated the drought (October 2020 SPEI compared to SPI). The heat in October was a continuation of excessive heat which has lasted much of this year, and was especially extreme during the last three to six months. The heat of the last six months contributed to excessive evaporative demand in the Southwest as well as the Northeast.”
All of which could become distressingly normal, if the projection of the climate modelers prove accurate.
Arizona, California and Nevada are likely to face a big increase in “atmospheric thirst” as a result of rising average temperatures, according to a study by researchers from the University of California and Scripps Institution of Oceanography published in Earth’s Future.
The researchers predict up to 10 times as many days with “extreme” fire danger, as fuels dry out faster in the spring and remain dry longer into the fall and winter.
Multi-year droughts are likely to increase 15-fold, according to the projections based on the assumption the average temperatures will continue their slow, steady rise.
The rising temperatures will increase evaporation from the soil and plants, while also putting more heat stress on the plants. This will increase fire danger, stress ecosystems and affect agriculture where there isn’t enough additional irrigation water to offset the effect.”