Despite heading into the middle what is normally snow season, areas from Oregon to Nevada aren’t necessarily feeling the chill. Months of above-average temperatures and a slow start to the winter wet season have combined to leave much of the Western United States facing a snow drought, with snow levels in many places measuring less than a quarter of their historical average.
Unlike its more familiar meteorological cousin, a snow drought doesn’t necessarily mean that no precipitation is falling. But in places like Oregon, warmer temperatures mean that precipitation this year has largely fallen as rain — an ominous sign for the region’s winter economy, and a worrying harbinger of a potentially water-scarce spring and summer.
Snow levels throughout much of Oregon are less than half of what they would normally be at this time of year. And while recent storms have brought some snow to mountainous areas, Oregon’s snow totals will likely be below average for the rest of the season due to a particularly slow start.
“When we talk about snow drought, it’s difficult because if it’s too warm up in the mountains for the precipitation to fall as snow, then it’s not serving us very well,” Kathie Dello, associate director of the Oregon Climate Change Research Institute, told ThinkProgress. “It’s either running off early or filling up reservoirs early. We really need it to stay as snow until spring.”
In California, snow totals are about 30 percent of what usually falls at this time of the year. Like in Oregon, above-average temperatures have caused most precipitation to fall as rain, but in southern California, precipitation has rarely fallen at all — much of the southern part of the state is currently experiencing moderate drought due to exceptionally low amounts of precipitation over the last several months.
But even if southern California hadn’t experienced that stretch of dry weather, experts say that rising temperatures would still have contributed to low snowpack levels.
“We do anticipate changes in precipitation, but even if we didn’t have any changes in precipitation, there would still be a big impact on snowpack due to warming,” Alex Hall, director the Center for Climate Science at UCLA, told ThinkProgress.
In Colorado, snow levels are the lowest that they have been in more than 30 years, prompting concerns that a poor snow season could have a negative effect on the state’s winter tourism industry. Colorado is one of the country’s busiest winter recreation destinations: Close to 13 million people visited the state to ski, snowboard, or enjoy the mountain snow in the 2016-2017 season.
Even with half of the snow season still to come, snow drought can have an immediate impact on local economies that depend on winter recreation. In Oregon, several winter recreation areas were forced to delay opening for over a month, causing economic losses for communities that depend on seasonal travelers and tourism. In Colorado, Aspen Skiing Co. — which normally employs seasonal workers for a number of mountains in the state — opened a soup kitchen for employees who couldn’t find work due to low snow levels.
“That’s a huge hit to our economy, the economies of some of these communities, people who are seasonal workers,” Dello said of the late openings. “It really cascades down the chain.”
But beyond immediate economic impacts, low snow levels can have serious ramifications for water resources in states that have come to depend on snow melt to recharge water reservoirs. When snow melts early — or when snow falls as rain instead — reservoirs tend to fill up earlier in the season, forcing states to drain water before the driest stretches of spring or summer (reservoirs have to be kept at a level where they can absorb extreme precipitation events, which helps prevent floods). If snow melts before those reservoirs can be recharged, that means that communities that depend on those reservoirs for their water can be left without many options.
“In the average year, the snowpack is storing as much water as all of the storage capacity of all of the reservoirs in the state,” Hall said. “The snowpack acts as a storage facility for the water until it is most needed in the summertime. If you lose that, its like losing a huge storage facility for water.”
Across the West, natural resource managers have expressed hope that the snow will still come, and will remain as snow long enough to feed reservoirs well into the summer.
“It is still hard to tell what the water supply implications are going to be. We are still somewhat early in the season,” Colorado Water Conservation Board climate change specialist and drought program manager Taryn Finnessey told the Denver Post in January.
But the trend towards less snow — both due to snow falling as rain, or snow melting earlier — is only likely to become more common as climate change continues to raise temperatures. A study from the University of Colorado, for instance, found that snowpack in the southern Sierra Nevada mountain range tends to shrink by 10 percent for each degree Celsius of warming.
“We’re definitely stacking the deck with more of these low snowpack years due to temperature,” Dello said. “We’ll [still] have big snowpack years, but we’re going to see more of these low ones creep in.”