Fat flakes of snow tumbled from the sky and collected on Frank Gehrke’s shoulders as he stood high in the Sierra Nevada on March 30, measuring the winter’s frozen bounty. Gehrke, head snow surveyor at the California Department of Water Resources, plunged a hollow metal pole into the snow, then weighed its contents. His measurements showed that the snow was nearly 8 feet deep at Phillips Station, south of Lake Tahoe, and the amount of water held within it was 183 percent of the long-term average for this time of year. Overall, the Sierra snowpack was 164 percent of the historical average. That’s a stark contrast to the record low April 1 reading two years ago, when the statewide snowpack was just 5 percent of average. “This is an extremely good year from the snowpack standpoint,” Gehrke said in a statement. This year’s abundant snow, he added, is providing “great reservoir recovery.”
Following a years-long drought — which California Gov. Jerry Brown declared over on April 7 — this winter’s record-breaking wet weather has recharged surface water supplies across California: By the end of February, reservoirs in about 80 percent of the state’s river basins were above historical average capacity. Reservoir levels are also above average in most Western states, including Nevada and Wyoming, which each experienced their wettest winter on record. This year’s plentiful precipitation is pushing water-forecasting models to their limits as analysts predict summer water supply based on winter rain and snowfall amounts outside historical norms. While variable winter weather isn’t new in the West — wild swings in precipitation from year to year are a fact of life here, experts say — climate change may be intensifying those fluctuations. The lessons forecasters and reservoir managers are learning this year could help them deal with the uncertain future ahead.
Several states across the West received substantial snow this winter, says Jolyne Lea, a hydrologist with the National Water and Climate Center in Portland, Oregon. “From the Sierra through Utah and into Colorado, there was a swath of very heavy snow,” Lea says, while other areas experienced more typical precipitation. Montana’s statewide snowpack, for example, was 92 percent of the historical average by the beginning of April. The National Water and Climate Center, part of the Natural Resources Conservation Service, creates forecasts of spring and summer runoff using models that take into account historical data on snow, rain, stream flow and other factors. Municipalities, irrigation districts, reservoir managers, farmers, ranchers, fish and wildlife managers, recreational rafters and even bankers eyeing agricultural loans use the forecasts, Lea says.
Source: High Country News
This shows the weather extremes that many are facing across the western US that have seen little to no historical precedent in recent written record. In California in particular, the state suffered a drought for a number of years until the 2016-2017 snow season, when suddenly the snowpack was well over 100% of historical average. Once again the Earth wobble and the warming Earth are to blame.