Cold, snowfall heading this way
Winter doesn’t officially begin until Dec. 21, but weather patterns in the Inland Northwest are finally beginning to change. Skiers and snowboarders are eagerly awaiting the arrival of big snows.
Between now and the end of January, it appears we’ll be in the grips of a colder and snowier pattern for our area as well as much of the Pacific Northwest. I’m expecting about 70 percent of our season’s snowfall to blanket our region during that time. This would translate to about 35 inches at the airport and close to 50 inches in Coeur d’Alene. In the higher mountains, up to 150 inches of new snow can be expected during the next six weeks. Despite the expected increased snows, we should receive far less than what we saw last season.
At Spokane International Airport, the final total for the 2007-08 season was 92.6 inches, less than an inch of the all-time record of 93.5 inches set in 1949-50. In the northwestern portion of Coeur d’Alene, an incredible 172.9 inches was gauged. The old record was 124.2 inches set in 1915-16.
From looking at the figures between Spokane and Coeur d’Alene, one will likely notice large differences in precipitation for two regions that are relatively close to one another. As they say, it’s all about “location, location, location.”
Our scenic Inland Northwest, with its lakes, mountains and valleys, hosts a variety of different microclimates within a relatively small area. The differences in temperatures and especially precipitation are primarily caused by elevation and proximity to water.
Spokane International Airport is at 2,372 feet, Felts Field is at 1,952 feet and the Coeur d’Alene airport is at 2,320 feet. Based on elevation, it makes sense that Felts Field in the Spokane Valley would be on the lowest end of the snow totals, as there are plenty of times when it is snowing in Spokane and raining in the Valley. But, Coeur d’Alene usually receives much more rain and snow.
To get moist air to precipitate, it has to be lifted. There are many ways this can happen in the atmosphere, but the mountains play a key role, especially in our region. As moist air moves toward a mountain, or mountain range, it is forced to rise. This sharp rising motion enhances the precipitation process as the air is cooled.
In a prevailing westerly upper-level wind-flow, central Washington is located in the rain shadow of the Cascades where air is traveling down the mountain, warming and drying instead of rising and cooling. As a result, average precipitation totals in central Washington are much less than Spokane.
Continuing eastward, the terrain begins a gradual upward slope, with increasing precipitation totals toward the Idaho border. Lying just west of the Rockies, North Idaho is in a favored upslope region. For this reason, Coeur d’Alene will usually end up with higher snow and precipitation totals than Spokane.