Thanks to a series of recent snow storms, drought conditions in Colorado have shown substantial improvements over the past month, including the past week, with extreme drought nearly disappearing from the state. A remaining sliver of exceptional drought – the worst category – in southwest Archuleta County disappeared in the latest report from the National Drought Mitigation Center.
The top state agencies that manage water and wildlife resources in California submitted a package of voluntary agreements with water districts to the State Water Resources Control Board on Friday, as an alternative to controversial flow requirements approved in December for the Tuolumne, Stanislaus and Merced rivers. The agreements, hammered out in the waning hours of Gov. Jerry Brown’s administration and favored by Gov. Gavin Newsom, combine increased river flows with a larger set of tools for restoring salmon in rivers that feed into the San Joaquin-Sacramento Delta.
The storms hitting California in February have left their mark on California’s largest and most important water reserve. Shasta Lake jumped 39 feet in elevation since February 1 and as of Tuesday it was at 85 percent of capacity and only 25 feet from its crest. Amid a wet winter, dramatic lake level rises have been common this year. Folsom Lake east of Sacramento rose 30 feet in January, while Lake Oroville shot up 75 feet in February.
Powerful rainstorms have battered Northern California this week. The culprit? Atmospheric rivers. The rains were born far away, deep in the tropical Pacific, where water evaporated from the warm ocean surface and fizzed into the atmosphere. The drenched air parcel flow then moved sinuously along, an “atmospheric river” winding its way toward land. When that wet air hit a coast—in this case the West Coast of the U.S.—it dumped that water out as the rain and snow that has overwhelmed Northern California this week.
Monday is the new deadline for all parties to sign the drought contingency plan — the deal between seven states to share less water on the Colorado River. Arizona state lawmakers approved the deal ahead of a late January deadline but the federal government said it didn’t meet the mark. Meanwhile, some say the plan doesn’t go far enough to ensure Arizona has enough water for the future.
It’s no surprise, but feet upon feet of Sierra snow across multiple storms in February translated to healthy snow water content for California. How healthy? Department of Water Resources officials observed more than double what they measured last month at Phillips Station near Echo Summit, recording 113 inches of snow depth with a snow water equivalent of 43.5 inches Thursday, according to a news release. A month ago at the February survey (Jan. 31), snow-water equivalent had reached 100 percent of the statewide average (17.3 inches) at the February survey.
The U.S. Drought Monitor (USDM) is released weekly to indicate what areas throughout the United States are experiencing some level of the five-category drought. The USDM levels range from the lower end of Abnormally Dry to the highest level of drought, Exceptional Drought. During the recent five-year drought, which ended with the record-setting winter of 2016-17, Californians were faced with water shortages and much of the state ranked in the Extreme and Exceptional categories.
Back-to-back storms hammering California this winter have nearly washed drought off the California map. After the recent atmospheric river, only a lingering sliver of “moderate drought” conditions remains near the Oregon border. The federal Drought Monitor Map, one way to measure drought that’s mainly used in agriculture, shows two percent of the state with “moderate drought” conditions and 13 percent abnormally dry in its Feb. 28 report.
Oroville Dam is currently the only reservoir in the state that’s below average elevation — but that’s on purpose, said the state’s Department of Water Resources. “If the lake begins to rise very quickly in the coming weeks due to large storms and increased inflows, then DWR may consider using outflow mechanisms,” the department said in a press release. That could include using the main spillway for the first time since it was rebuilt. The reservoir is currently at 55 percent of total capacity, said DWR’s assistant director of public communications, Erin Mellon. That’s about 80 percent of average.
Atmospheric river storms pounding Northern California with rain have also brought epic snow to the Sierra. Meteorologist Jim Mathews says that since 1950 only six years have surpassed the total “snow water content” that California has right now. The state’s snowpack — measured using the snow’s water content — is at 130% of its usual level on April 1 (after that date, the snow tends to begin to melt). It’s at 150% of the amount that’s normal for this time in February.
