More blizzards equals less snow — Tahoe’s future climate equation?
March 1, 2013
Massive blizzards may become the norm for Tahoe, but don’t get your powder boards out just yet — that doesn’t necessarily mean more snow. A new report from the Environment America Research & Policy Center found that extreme rain- and snowstorms in the U.S. now happen on average 30 percent more frequently than in 1948. And the Associated Press reported last week on two upcoming studies that explore how intense, discrete events might not translate to more snow accumulation. The first report found that the number of extreme U.S. snowstorms in the past 50 years is more than double the number from the previous 60 years, according to the Associated Press. The piece also quoted an upcoming article from the Journal of Climate that predicts annual snowfall throughout the world will decrease by more than a foot by mid-century.“You may end up with fewer total events over a season that yield seasonal snowfall,” California State Climatologist Michael Anderson said. “The dynamics of the events that happen are hypothesized to intensify.”Much of the snowpack around South Lake Tahoe came from a monster system that rolled through in December. Many California reservoirs hover around average capacity for the date because of the atmospheric river that soaked the state in November. The Northern California region just went through the driest January and February on record since 1920, but those intense, one-time events have buoyed the state’s water resources. “Reservoir storage is still above average as a result of the atmospheric river event we had back in the end of November. That’s really been the bright spot in terms of the water cycle for this year,” Chief of the Cooperative Snow Survey Frank Gehrke said at Thursday’s snow survey. A warming atmosphere contains a larger amount of energy, allowing for more dynamic weather patters, California Department of Water Resources Jeanine Jones said. Jones compared the situation to a boiling pot of water. Less vapor rises from the water’s surface when it’s simmering. Turn it up to a boil though, and you increase the amount of energy and the volatility of the mix. While Jones said all the climate models agree that the atmosphere is warming, there’s less consensus on the effect those rising temperatures will have on precipitation in certain regions. Northern California is in one of those gray areas. Breaking down global climate models to the regional level is still an evolving science, Jones said. California already relies on 10 to 12 storms a year for its water content, Jones said. If the state gets pounded by less frequent, more intense storms, Department of Water Resources staff will have to rethink the hydrology of the reservoirs — storage areas meant to collect water over an extended period of time. “We’re bouncing around on the extremes more and that’s one of the expected outcomes of climate change,” Jones said.— The Associated Press contributed to this report.