Halfway Through Season, Snowpack in U.S. West Thins

An animation showing snowpack in the western United States compares conditions at the end of January, 2011 and this year. (Maps: NOAA NOHRSC; Animation: Tom Yulsman) January was not kind to snowpack in the mountains of the U.S. West — from which most residents of this part of the country derive their water. This week is about the half-way mark for snow season in the West, and scientists have fanned out throughout the region to measure the amount of water locked in snow — a measure called "snow water equivalent." This is a monthly ground-truthing exercise to back up an automated monitoring system called SNOTEL. What they've been finding, combined with SNOTEL and drought data, is concerning. I created the animation above to provide a visual sense of what's happening. The first frame shows the snow water equivalent in the mountains of the West at the end of January 2011, when drought was absent from most of the region and conditions were closer to the long-term average. The second frame is from today. The change is pretty obvious.