Reduced spring, summer melt-off

Scientists and water managers say that at some point California’s snowpack could simply disappear. This would leave the state without the crucial spring and summer melt-off that fills rivers and streams, nourishes plants and animals, and provides a huge chunk of the water supply. It would also be devastating for the ski industry.

This snowless future, according to a new study led by researchers at Lawrence Berkeley National Laboratory, could arrive in California’s Sierra Nevada in as soon as 25 years. The study is among many to detail the decline in snow, but it is unique in synthesizing decades of research to nail down exactly when the snow might be gone. And it offers a timeline that is alarmingly short.

“Warming just doesn’t allow for snow to persist,” said Alan Rhoades, a hydroclimate research scientist at Lawrence Berkeley Lab and one of the lead authors of the paper. “Our one major goal was to identify how much time we have to roll out adaptation strategies.”

Experts say that preparing for a Sierra with less snow won’t be easy, or cheap, but they agree it must be done. In recent decades, the snow season has shrunk by a month. Snow levels have reportedly moved upward by 1,200 feet.

The new study, published last month in the journal Nature Reviews Earth & Environment, projects that by the late 2040s, half of the area historically covered by snow in the Sierra will likely have “low or no” snow for five straight years, given current warming trends. By the late 2050s, it could be 10 straight years that the same area sees low or no snow.

The paper defines “low snow” as when snowpack — technically, the snow-water equivalent, or how much water the snow releases when it melts — falls within the lower 30th percentile of its historical peak. “No snow” is defined as when the snowpack falls to or below the 10th percentile.

The study’s findings are based on a review of hundreds of scientific papers on snowpack, 18 of which contain quantitative projections. The authors looked not only at the Sierra Nevada but at the Cascades in the Pacific Northwest and parts of the Rockies.

In all of these mountain ranges, the study finds that at least half of the historically snow-covered spots will see low or no snow for five straight years by the 2060s, at the current rate of warming.

Leave a comment

Your email address will not be published.