The California Department of Water Resources (DWR) will conduct its first snow survey of the new winter season at 11 a.m. Thursday, Jan. 4, near Lake Tahoe. The manual survey location is Phillips Station at Highway 50 and Sierra at Tahoe Road, about 90 miles east of Sacramento.

This will be the first of five monthly measurements that will aid water supply planners in estimating the amount of spring snowmelt runoff into reservoirs.

Manual measures of the snowpack is needed to confirm the reports that come in from automatic sensors placed in snowpack areas, said Maury Roos, chief hydrologist with the DWR's flood management division.

Snow-water content is important in determining the coming year's water supply. The measurements help hydrologists prepare water supply forecasts as well as provide others, such as hydroelectric power companies and the recreation industry, with much needed data.

Monitoring is coordinated by DWR as part of the multi-agency California Cooperative Snow Surveys Program. Surveyors from more than 50 agencies and utilities visit hundreds of snow measurement courses each month to gauge the amount of water in the snowpack.

Roos said he gathers much of the snowpack information during the season from more than 100 automatic sensors, called "snow pillows."

The snow pillows, about 115 in all, he said, are clusters of four rectangular, stainless steel sensors filled with an alcohol mixture. Roos said they transmit the weight of the snow to a transducer, which then calculates the amount of water the snow layer contains.

Besides snowpack and water depth, Roos said the sensors also track information such as temperature and rainfall.

 

A Jan. 3 report on the Department of Water Resources Web site shows the statewide snowpack is averaging 6 inches of water content. That is 22 percent of what is considered a full snow pack, normally reached in April, and 59 percent of normal for this time of year. The state's northern Sierra Nevada/Southern Cascades region leads the way with 68 percent of average for this time of year.

If the snowpack is below average, it will become more apparent early next year, said Roos. That's because the winter months of December, January and February account for the overall precipitation, he added.

On the Web: For the latest snowpack information, visit cdec.water.ca.gov/snow/current/snow/.

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