Wednesday, April 1, 2015

Manual snow survey finds no snow at all

April 1 is usually considered the peak date for the Sierra snowpack, but the warm temperatures we've seen in March have obliterated an already meager supply of snow water content.

From the Department of Water Resources:
The California Department of Water Resources (DWR) found no snow whatsoever today during its manual survey for the media at 6,800 feet in the Sierra Nevada. This was the first time in 75 years of early-April measurements at the Phillips snow course that no snow was found there.

Governor Edmund G. Brown Jr. observed the survey, which confirmed electronic readings showing the statewide snowpack with less water content today than any April 1st since 1950.

Attending the survey with Governor Brown was DWR Director Mark Cowin, who said Californians can expect to receive almost no water from the meager snowpack as it melts in the coming weeks.

“Today’s survey underscores the severity of California’s drought,” he said. “Water conservation must become a way of life during the worst drought in most Californians’ lifetimes.”

Today’s readings are historically significant, since the snowpack traditionally is at its peak by early April before it begins to melt. Electronic readings today found that the statewide snowpack holds only 1.4 inches of water content, just 5 percent of the historical average of 28.3 inches for April 1. The previous low for the date was 25 percent in 2014 and 1977.

The Phillips snow course, which has been surveyed since 1941, has averaged 66.5 inches in early-April measurements there. Four years ago today, the measured depth at Phillips was 124.4 inches. The deepest April 1st Phillips measurement was 150.7 inches in 1983, and the lowest previously was 1.04 inches in 1988. Photos of previous surveys at Phillips can be found here. Images from today’s survey will be posted at that link as soon as possible.

Electronic readings indicate the water content of the northern Sierra snowpack today is 1.4 inches, 5 percent of average for the date. The central and southern Sierra readings were 1.5 inches (5 percent of average) and 1.3 inches (5 percent) respectively.

Today’s manual survey was the fourth of the season conducted for the news media at the Phillips snow course just off Highway 50 near Sierra at Tahoe Road 90 miles east of Sacramento. When DWR conducted the first three manual surveys on December 30, January 29 and March 3, the statewide water content in the snowpack was 50 percent, 25 percent and 19 percent respectively of the historical averages for those dates. The decline reflects California’s significantly lower precipitation and the warming trend that made this winter the warmest in the state’s recorded history. What precipitation there was fell mostly as rain due to warmer temperatures.

In what were considered normal precipitation years, the snowpack supplied about 30 percent of California’s water needs as it melts in the spring and summer. The greater the snowpack water content, the greater the likelihood California’s reservoirs will receive ample runoff as the snowpack melts to meet the state’s water demand in the summer and fall.

Little precipitation has fallen in Northern California since early February. The eight weather stations there that have been monitored for generations have recorded 31.7 inches since the beginning of Water Year 2015 on October 1. That is 76 percent of the historical average for April 1. Further south, the five-station San Joaquin index has recorded 13.7 inches, 41 percent of normal for today’s date, and the six-station index in the Tulare Basin is similarly far below normal – 10.3 inches, or 42 percent of the April 1 average there.

California’s historically wettest winter months have already passed, and the drought is now firmly rooted in its fourth consecutive year. [...]

The major water supply reservoirs are storing more water this year than last but are still far below the historical average for early March. Lake Oroville in Butte County, the State Water Project’s (SWP) principal reservoir, now holds 51 percent of its 3.5 million acre-foot capacity (67 percent of its historical average for the date). Shasta Lake north of Redding and the federal Central Valley Project’s (CVP) largest reservoir, is at 59 percent of its 4.5 million acre-foot capacity (73 percent of its historic average). San Luis Reservoir, which serves both the SWP and CVP, holds much more water than it did one year ago due to recent water deliveries to the reservoir as a component of the agencies’ drought management strategy. San Luis holds 66 percent of its 2 million acre-foot capacity (73 percent of normal for the date).
Updated electronic snowpack readings can be found here.

The governor has imposed mandatory water restrictions for the first time, as the AP reports on our website. State officials will be holding a teleconference this afternoon to discuss the drought, and I'll be listening in. For more updates, check back here and at CapitalPress.com.

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