Snow surveyors confirmed that water content in the mountain snowpack is well below normal for the date.

The snowpack hasn’t actually lost much water content since the season’s first survey on January 2, when it was 134 percent of normal for that date, but it hasn’t continued to build as winter has deepened because of the continuing warm weather that set in after the storms of late November and early December. In other words, the snowpack has not kept pace with the calendar.  As a result, today’s snowpack water content is only 66 percent of average for this time of year, and only 57 percent of the average April 1 reading, when the snowpack normally is at its peak before beginning to melt into the state’s streams, reservoirs and aquifers.

The snowpack – often called California’s “frozen reservoir “– normally provides about a third of the water for California’s farms and communities.

With no precipitation in the forecast, the Northern California region whose storms fill key reservoirs that supply water to farms and millions of Californians is headed toward the driest January-February on record (since 1920).   This is the normally rain-rich, mountainous area from Shasta Lake in the north to the American River basin in the south, where a scant 2.2 inches of rain has fallen since December, 13 percent of average.   The next driest January-February was in 1991, with 4 inches of precipitation.

Forecasters note there could be a weather turnaround in March, but it is unlikely late-season storms will make up the water supply deficit.

“Near-record dry weather combined with pumping restrictions to protect Delta smelt are making this a gloomy water supply year,” said Department of Water Resources Director Mark Cowin. “This scenario is exactly why we need an alternative water conveyance system as proposed in the Bay Delta Conservation Plan to both protect fish species and give California a reliable water supply.”

Results of the manual snow survey readings by the Department of Water Resources (DWR) off Highway 50 near Echo Summit are as follows:

Location

Elevation

Snow Depth

Water Content

% of Long Term Average

Alpha

7,600 feet

34 inches

13.6  inches

49

Phillips Station

6,800 feet

29 inches

13.4 inches

                        54

Lyons Creek

6,700 feet

45.5  inches

15.5  inches

61

Tamarack Flat

6,500 feet

 inches

 inches

                  Missing

Electronic readings indicate that water content in the northern mountains is 70 percent of normal for the date, and 62 percent of the April 1 seasonal average.  Electronic readings for the central Sierra show 67 percent of normal water content for the date and 58 percent of the April 1 average.  The numbers for the southern Sierra are 60 percent of average for the date and 51 percent of the April 1, full-season average.

DWR and cooperating agencies conduct manual snow surveys around the first of the month from January through May.  The manual measurements supplement and check the accuracy of the real-time electronic readings from sensors up and down the state.

DWR currently estimates that it will be able to deliver 40 percent of the slightly more than 4 million acre-feet of State Water Project (SWP) water requested for this calendar year by the 29 public agencies that supply more than 25 million people and nearly a million acres of irrigated farmland.  The delivery estimate may change to reflect changing conditions.  The final allocation of State Water Project water in calendar year 2012 was 65 percent of requested deliveries.  The initial delivery estimate for calendar year 2011 was only 25 percent of requested SWP water. However, as winter took hold, a near record

snowpack and heavy rains resulted in deliveries of 80 percent of requests in 2011. The final allocation was 50 percent in 2010, 40 percent in 2009, 35 percent in 2008, and 60 percent in 2007. The last 100 percent allocation -- difficult to achieve even in wet years because of pumping restrictions to protect Delta fish -- was in 2006.

Despite the dwindling snowpack, most key storage reservoirs are above or near historic levels for the date thanks to November and December storms.  An exception is San Luis Reservoir, a critical offstream reservoir south of the Sacramento-San Joaquin Delta that is only at 69 percent of its historic level for the date.  San Luis normally is filled by pumping from the Delta, but today is only 60 percent full because of the Delta smelt pumping restrictions.

Lake Oroville in Butte County, the State Water Project’s principal storage reservoir, is at 113 percent of its average level for the date (80 percent of its 3.5 million acre-foot capacity). Shasta Lake north of Redding, the federal Central Valley Project’s largest reservoir with a capacity of 4.5 million acre-feet, is at 107 percent of its normal storage level for the date (79 percent of capacity). 

Electronic snowpack readings may be found at: http://cdec.water.ca.gov/cgi-progs/snow/DLYSWEQ.

Electronic reservoir level readings are available at: http://cdec.water.ca.gov/cgi-progs/products/rescond.pdf.