The Sierra Nevada snowpack has shrunk to 66 percent of average, according to a survey Thursday by the state Department of Water Resources.
That's a drop from 134 percent on Jan. 2, a result of the driest January-February period in recorded history in the northern Sierra Nevada.
The state's major reservoirs hold near-average water supplies as of Thursday, thanks to a wet November and December. But without more storms in the final month of winter, they are likely to shrink rapidly come summertime.
DWR estimates it will be able to deliver 40 percent of the 4 million acre-feet of water requested by the 29 public agencies it serves. They supply more than 25 million people and nearly a million acres of farmland from San Jose to San Diego. San Joaquin Valley farmers served by the U.S. Bureau of Reclamation have been told to expect 25 percent of requested water deliveries.
The city of Sacramento has its own water rights in the Sacramento and American rivers and is not affected by these estimates. Some suburban communities in the metro area, however, rely on water stored in Folsom Reservoir, and they were told by Reclamation to expect 75 percent deliveries.
These estimates may improve if wet weather returns.