#WeatherAuthority: Sierra snowpack deepest in nearly 30 years
LAS VEGAS (KSNV) — The Sierra Nevada snowpack makes up nearly 33% of California's water supply and is currently at its highest level since 1995. The good news is that the drought could be coming to an end, but there are also concerns that the spring months may get too warm too quickly resulting in a rapid runoff, or a few warm spring storms could melt it too early and trigger major flooding.
The snowpack was 208% of its historical average on January 31st. At this time last year, the snowpack ranged from 85 to 90% of the historical average. What a difference a year can make. The last time there was as much snow, 28 years ago, on Feb. 1, 1995, it was 207% of normal.
Since 1950, only twice has the snowpack, heading into February, been higher than what it is now. You have to go back to 1952 (267% of the average) and 1969 (230%).
Obviously, the ski resorts are loving it! On February 1st Palisades had a base depth of 11 feet, Kirkwood 12 feet, and at Mammoth Mountain, it was nearly 20 feet deep. Some of the deepest in years heading into February.
MORE | #WeatherAuthority: Current snowpack in good shape, what's in it for Lake Mead?
A series of nine atmospheric river storms began around Christmas and continued for three weeks. Since then, temperatures have been cool in the mountains, preserving much of it. That's huge!
The snowpack typically melts in late spring and early summer. Billions of gallons pour down more than a dozen Sierra rivers. The water is caught in major reservoirs. It also recharges underground aquifers and provides food and habitat for fish and wildlife.
The water also began filling reservoirs across the state. The largest, 35-mile-long Shasta, near Redding, on Tuesday was 56% full, or 87% of its historic average for that date. The second largest, Oroville, in Butte County, was 65% full, or 112% of its historic average.
The biggest concern is that a couple of warm spring storms could bring heavy rainfall leading to major flash flooding. The "Pineapple Express" got going in 1997 which drenched the Sierra around New Year's Day.
Yosemite Valley experienced its worst floods in a century. Half of Yosemite Lodge was destroyed. Levees broke, causing major flooding in Marysville, Yuba City, and other communities. When the flooding finally stopped. 48 of California's 58 counties were declared disaster areas and damage totaled $1.8 billion.
The forecast for February and March calls for cooler-than-average temperatures will equal chances for either wetter or drier than normal conditions.
