Which way is wind blowing? Ski resorts want to know

In a year when snow in the valleys has definitely been absent, how is it that some local ski resorts are dealing with less-than-stellar snowfall amounts, while others are getting more of the fresh powder? I’ve written numerous articles explaining how snow amounts can very widely across short distances. A location’s proximity to mountains, its elevation, and its tendency to get caught under the occasional small-scale snow bursts, all affect how much snow is seen. As a general rule, higher elevations will see more snow due to the colder temperatures. A city will also see more snow (relatively speaking) the closer it is to the windward side of a mountain. The sharp rise of the terrain, which forces air upward, aids the formation of precipitation (assuming there is enough moisture). Looking at several of the local ski resorts, Silver Mountain, Lookout Pass, Schweitzer Mountain, 49 Degrees North, and Mount Spokane, there is another factor to consider, when we see one location enjoying a lot more snow than another.

The orientation of a mountain range and the prevailing winds in that area, have a lot to do with why some ski resorts are getting the benefit of more snow this year. Last winter, it was the “westerlies” which prevailed, meaning winds that generally blew from west to east. This particular wind pattern gave the edge, when it came to snowfall, to the Northern Rockies, a north/south oriented mountain range. Westerly winds hitting the mountain range in a perpendicular fashion, would be quickly forced upward, squeezing out all the available moisture.

Now let us look at the mountains of Northeastern Washington and the Northern Idaho Panhandle which are banded in more of a west/east fashion. You would get your best “bang for the buck” when it comes to snowfall, from a prevailing flow which included a southerly component, which is what we’ve seen this winter under milder southwest flow. I would highly recommend checking out a colored topographic map of the Northwest to get a visual of what I’m talking about. One can be seen at www.tripleblaze.com/blog/ wp-content/uploads/2009/02/ pacific-northwest-trail-map.jpg.

Warmer and drier than normal weather has dominated the first half of February, and it looks like that trend will continue for the rest of the month. The valley rain and mountain snow over the past few days has definitely been needed, as both Spokane and Coeur d’Alene are already significantly below normal in precipitation for both the water and calendar year. There are just a few months left in which to build up an adequate snowpack in the mountains for the warm season’s water needs.