California Drought: Storms Help Reservoir Storage But Not Snowpack

The weekly U.S. Drought Monitor Thursday reports the recent Pacific storms have lessened the "extreme" category of drought in some parts of California.

But the report goes on to say that the February precipitation did nothing to help the "well below normal" snowpack in the Sierra Nevada. 

"The storms were the first significant precipitation event to affect California since mid-December," the report stated. 

But those warm storms brought mostly rain to Northern California and did little to help the mountain snowpack, with snow falling mostly at higher elevations.

"Overall, the storms had little impact on the well-below-normal snowpack conditions across the Sierra Nevada and Cascades ranges," according to the report.

"In the northern half of the Sierra Nevada Range, rainfall accumulations ranged from three-to-ten inches, and the greatest accumulations occurred on the western slope between 2,000 and 7,000 feet in elevation. Snow levels were generally high (above 8,000 feet) throughout the storms, and the cumulative effect of the snowfall received did not have a significant impact on the poor snowpack conditions across the range."

Along with California, "mountain snowpack conditions are currently below normal across the Great Basin and Southwest as well as in parts of the Intermountain West."  

The storms did benefit the larger reservoirs in California.

"On a more positive note, runoff associated with the [February storms] provided the addition of approximately 500,000 acre feet of inflow to the four major reservoirs (Folsom, Oroville, Shasta, and Trinity) in Northern California."

But the report says reservoir storage "remains below normal in Arizona, California, Nevada, New Mexico, Oregon, and Utah." 

'Unprecedented Drought Conditions'

A new report warns that the U.S. Southwest and Central Plains could face "megadroughts" during the second half of this century. And those droughts could last for decades.

The Associated Press says scientists write in a study in the journal Science Advances that global warming will lead to "unprecedented drought conditions" - the worst in more than 1,000 years.

The study is based on current increasing rates of rising emissions of carbon dioxide and complex simulations run by 17 different computer models, which generally agreed on the outcome.

The Southwest will see less rain. But the biggest problem in both regions will be the heat, which will increase evaporation and dry out the soil.

The lead author is NASA atmospheric scientist Benjamin Cook, who says, "We're going to have to think about a much drier future in western North America."