California Snowpack Levels Far Below Average

Although there’s more snow than there was a month ago, the Sierra snowpack remains at levels well below the average.

On Thursday, managers for California’s Department of Water Resources found little snowpack when they conducted this winter’s second manual snow survey at Phillips Station, east of Sacramento.

Measurements showed that the snow water equivalent at Phillips Station is just  2.6 inches–14% of the average for this date. Snow water equivalent is the amount of water contained within the snowpack, or, in other words, the depth of water that would result should the entire snowpack melt.

Statewide snowpack measurements are only slightly higher: electronic snow sensors across the Sierra Nevada show that snowpack levels are only at 27% of what is normal for February 1st, a level rather close to the 25% recorded in 2015 at this date, a year when California saw the worst snowpack on record.

“It’s not nearly where we’d like to be,” said Frank Gehrke, Chief of the California Cooperative Snow Surveys Program, in a video posted by the Department of Water Resources.

So, why is snowpack important?

Most of California’s precipitation falls during the winter, accumulating as snow at high elevations in the Sierra Nevadas and Southern Cascades. From April to July, as temperatures warm, this snow melts and runs off, feeding rivers and streams in California.

Normally, snowpack provides one-third of California’s water supply. The snowpack affects Davis’ water supply, since the City of Davis now relies on surface water from the Sacramento River as its primary source of water. Previously, the city relied solely on groundwater.

The water that feeds into the Sacramento River ultimately comes from a mixture of tributary streams, fed by rainfall and snowmelt, and springs, so water stored by the snowpack is an important source of Davis’ water supply.

How does this year’s snowpack compare to previous years?

This year’s warm, dry winter provides quite the contrast to last year, when the snowpack was much higher than average. On February 1st, 2017, the snowpack was 174% of the historic average for that date.

During California’s recent historic drought, however, the story was quite different. 2015 saw the lowest snowpack level for the Sierras since monitoring began in 1950: On April 1st, 2015, snow water equivalent in the Sierra snowpack was only 5% of the historic average.

And the snowpack wasn’t just the lowest it’s been since 1950. Using tree ring data, scientists found that the 2015 snowpack was the worst it had been in 500 years.

So it’s concerning that current snowpack levels–27% of average–are so close to the 25% seen in 2015 at this time.

According to the U.S. Drought Monitor, currently 73% of California is abnormally dry, including the 43% of the state that is in a moderate drought. This means that over 24 million California residents are currently living in drought areas.

Although “it’s worth being concerned” about the snowpack, said Doug Carlson, a spokesperson for the Department of Water Resources, “it’s too soon to be alarmed about what we see.”

The good news: California’s reservoirs

Though the snowpack is well below average, Doug Carlson points out that California’s reservoirs are full of water, thanks to last year’s historically wet winter.

As of a January estimate by the Department of Water Resources, 154 reservoirs are filled to above their historic averages. Total storage in these reservoirs is estimated to be at 106% of the average for this time of year, which can act as a buffer if drought does occur.

What changes are predicted for snowpack in the future?

Scientists expect that rising temperatures due to climate change will drastically reduce snowpack levels in the future.

In addition to less snow falling, rising temperatures will cause the snowpack to melt earlier, leading to a longer dry season and less water for Californians to use in the summer.

As for this year, only time will tell if California will experience another drought. The Department of Water Resources tends not to speculate, since “California’s weather is so variable,” as Doug Carlson explained.

As Frank Gehrke pointed out, “There’s still a lot of the winter left. Anything can happen as we move on through the rest of the season.”