Similar high-pressure zones pop up all the time during most winters, but they usually break down, allowing rain to get through to California. This one, ominously, has anchored itself for 13 months, since December 2012, making it unprecedented in modern weather records and leaving researchers scratching their heads.Meanwhile, the Sacramento area is beginning to respond:
...The current high-pressure ridge is even stronger and more persistent than a similar ridge that parked over the Pacific Ocean during the 1976-77 drought, one of the driest in the 20th century.
..."I wish I had a really good answer for this," said Daniel Cayan, an oceanographer and atmospheric scientist with the Scripps Institution of Oceanography in La Jolla. "It's unusual for the pattern to have not broken down to allow some relatively active, vigorous winter storm systems to track across California."
...Last year was the driest calendar year in recorded history in California in most cities, with records going back 160 years. The first snowpack reading in the Sierra Nevada earlier this month found a snowpack of just 20 percent of normal.
Meanwhile, major reservoirs in Shasta and Oroville are each 36 percent full, about half of normal for this time of year. San Luis Reservoir near Los Banos is 30 percent full, 42 percent of normal. Major Bay Area water agencies haven't yet called for mandatory summer water restrictions but are expected to make the decision in the next month or two, depending largely on whether the high-pressure ridge breaks down and rain falls.
State Department of Water Resources Director Mark Cowin told members of the California State Board of Food and Agriculture in Sacramento a week ago that his agency is likely to recommend that Gov. Jerry Brown declare a drought by Feb. 1, which would make it easier for water transfers between agencies and for emergency loans and other assistance.
...Since July 1, San Francisco has received 2.1 inches of rain -- just 20 percent of normal; San Jose has received 1.57 inches, or 26 percent of normal; and Oakland has received 2.08 inches, or 22 percent of normal.
Faced with historically low water levels on the American River and a long-range forecast providing little relief, the Sacramento City Council on Tuesday voted unanimously to enact severe water rationing on residents and businesses, while also boosting enforcement efforts against water scofflaws.
The council approved what city officials described as a “stage 2 water shortage plan,” requiring those who live and work in Sacramento to reduce their water use by between 20 percent and 30 percent.
...“We’re the river city and yet here we are having to make very difficult decisions,” said Councilman Allen Warren.
...The American River’s flow out of Folsom Dam is at its lowest point since 1993, putting it in “crisis mode,” Brent said. Folsom Lake is so depleted, remnants of a Gold Rush-era mining town buried by water for years have emerged in the barren lakebed.