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Can one monster storm save California from drought?

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The Sierra could get up to seven feet of snow

At Squaw Valley Alpine Meadows in Lake Tahoe, a fast-moving storm dropped 18 inches of new snow on Monday. Now, the region is braced for blizzard conditions.
Photo by Brandon Skinner, courtesy of Squaw Valley Alpine Meadows

After months of relatively dry weather in California, this winter’s biggest storm to date is set to deliver rain at lower elevations and feet of snow in the Sierra Nevada mountains. That’s good news for the precipitation-starved state, but will this storm be enough to mitigate the growing number of areas facing severe drought?

The National Weather Service reports that the storm will begin late tonight and impact the state through Saturday. The Bay Area will see about an inch of rain on Thursday and Friday, but the bigger action will be in the Sierra. In lower-elevation cities like Truckee, you can expect one to three feet of snow. Higher up along the Sierra Crest, amounts should total as much as three to seven feet.

High amounts of snow and wind gusts up to 100 mph will make travel difficult and raise the avalanche danger. The National Weather Service in Reno has issued a blizzard warning from Thursday morning to Friday morning, advising people that “Even a short walk could be deadly in these conditions.”

This week’s storm is a welcome break from the West’s abysmally dry winter that has revived concerns about water. Last winter, a record-breaking amount of snow lifted the state from a multi-year drought that caused Gov. Jerry Brown to declare a state of emergency.

Just recently, the statewide snowpack was at 19 percent and the Northern Sierra water stations had received even less precipitation than the historically low winter of 2014-2015. At the end of January, Los Angeles had seen just 28 percent of its average precipitation since October and the Bay Area is currently only at about 50 percent of average.

This winter’s lack of precipitation has plunged much of the state back into drought, with most of Southern California in moderate or severe drought and almost the entire state considered “abnormally dry.” Those assessments are made after considering the state’s precipitation totals, temperatures, moisture levels in soils, and water levels in streams and lakes. The recent lackluster numbers caused the LA Times to wonder whether Gov. Brown should have ever lifted the statewide water restrictions.

United States Drought Monitor

The big question remains: Is this upcoming storm—proclaimed to be the biggest of the winter so far—our last hope to avoid a potentially severe drought this summer? Unfortunately, the answer is no.

While any moisture is better than no moisture, even a five- or seven-foot storm won’t be enough to return the Sierra Nevada—which is the source of about 30 percent of California’s water supply—to normal. A foot or two of snow this past Monday was welcome news to snow-starved ski areas, but it only bumped up the snowpack by a few percentage points to 23 percent of average.

To put this in perspective, it takes about 10 inches of snow to deliver one inch of liquid water. To get to the average snowpack on March 1—which is about 25 inches of snow water equivalent—this week’s storm would need to drop over 16 feet of snow.

Of course, it’s rare for a single storm to end a drought. Last year, it took a successive number of large storms to make a difference. With forecasts of two to five feet of snow, the Mercury News reports that this week’s storm should take the snow pack from about 23 percent to about 40 percent of average. That’s better, but we’ll need several big storms in March to come close to ending the winter with an average snowpack.

Our advice: start hoping for a March miracle.