Nothing excites skiers and riders like fresh snow, and nothing can create a buzz in ski towns like talk of the next big storm. But it’s now about two months into the 2011/2012 ski season, and for much of the United States, there haven’t been many “next storms” to talk about. So what’s the deal?
This map gives a baseline to se how much snow we currently have compared to the average for this time of year. Image Courtesy of SNOTEL data network.
First, let’s get a baseline and see how much snow we have right now in mid-December, compared to the average for this time of year. The best resource for this is the SNOTEL data network, which is a set of hundreds of remote weather stations situated deep in the mountains across the western U.S. These stations are grouped by “river basin” (particular areas whose creeks and streams all drain into the same river). The map of river basins is color-coded by how much snow is on the ground compared to an average year, and the more yellow, orange and red you see—the less snow is on the ground. Unfortunately, the map has many below-average areas, most notably in Oregon, Nevada and the Lake Tahoe region of California where snowpack is 40 to 60 percent of average. On the bright side, one area that is doing well is the south, with 125 to 150 percent of average snow in Arizona, New Mexico and southern Colorado.
If you’re a fan of snow and a bit of a weather geek, you’ll realize that this map is the opposite of what we would expect during a La Niña winter. As a quick refresher, La Niña means the central Pacific Ocean is cooler than normal. Since this is a lot of water (the Pacific Ocean is pretty big), the change in water temperature affects weather patterns across the globe. For the U.S., the storm track usually shifts further north, which means more snow for northern areas and less snow for southern areas. The state of Washington did see a ton of snow in mid- and late-November as would be expected during a La Niña winter, but since then the tap has run dry.
For much of November and December 2011, the storm track has actually split as it moves into the U.S. Some energy stays north, and some drops south. This is not exactly normal for a La Niña winter, and it’s the reason why Arizona, New Mexico and southern Colorado have above average snowfall and most other areas have less snow than they would expect. The map shows a more typical La Niña storm track compared to what we’ve seen early this winter.
Of course, the big question is “when will the storms stop splitting?” In short, nobody knows. When the atmosphere gets into a rut, it can stay the course for four to eight weeks, or longer. During most winters, weather patterns shift back and forth every four to eight weeks (snowy west and dry east, then dry west and snowy east, etc). However, our current pattern seems to enjoy sticking around and isn’t showing many signs of letting up. Of course, a few storms can buck the trend and bring snow to otherwise dry areas, but it does appear our current situation of splitting storms will hold through the rest of December 2011.
On the bright side, many areas are still taking advantage of the typical cold December temperatures and making a good amount of snow. And Alaska is seeing a ton of snow, plus after a dry early season, big snowstorms are now hitting the Alps in Europe and their season is really picking up.
But if you’re yearning to feel that buzz as your ski town talks about the proverbial “next storm,” you might want to start up your snow dance because the atmosphere is going to need some encouragement in making a change back toward snowier weather.
Meteorologist Joel Gratz is the creator of opensnow.com and is based in Boulder, Colo.