La Niña boosts chances for white Christmas

Late last week, our first major snow was seen across the Inland Northwest. After today, we’ll pass the Thanksgiving holiday and be heading toward Christmas. The big question I’m starting to hear is, “Are we going to have a white Christmas?”

As mentioned in previous articles, the La Niña cooler-than-normal sea-surface temperature event in the south-central Pacific Ocean continues to maintain its strength. During La Niña events since 2007, our region saw near-record and record-shattering snowfalls. By contrast, during El Niño years, we typically see milder winter seasons, with more rain than snow falling in the lower elevations, as was the case during the winter of 2009-’10.

Based on current weather patterns, with a weak to moderate La Niña and increased solar activity, I believe the chances for that white Christmas are a little better than 50-50 in the Spokane area and about 70 percent in Coeur d’Alene. As the sun becomes more active, we sometimes see less snowfall, even during a La Niña year.

December 2008 was incredible in terms of snow and cold. At the Spokane International Airport, 61.5 inches fell, nearly 20 inches more than normal for the entire season. On Dec. 25, 2008, 20 inches of snow was on the ground. It was a chilly month, as the average temperature was 5.3 degrees below normal. Although December 2009 was also colder than normal, only 6.7 inches of snow fell. Last year, a total of 17.4 inches of snow fell at the airport. On Dec. 25, 3 inches of snow was on the ground.

The most snow ever measured at the airport on Dec. 25 was 23 inches back in 1951, when nearly 3 feet of snow was gauged in parts of North Idaho. In 1996, 19 inches was measured at the Spokane International Airport, with 10 inches on the ground in 1992, 1987 and 1916.

Since records have been kept in Spokane beginning in 1881, we’ve had 62 days with over a trace of snow on the ground on Dec. 25. Over the last 130 years, the Spokane region has seen a white Christmas about 48 percent of the time. In Coeur d’Alene, there have been 83 Christmases since 1895 with more than a trace of snow on the ground.

Despite the recent milder weather, more snow is expected late this month and into December. There will be a few storms, however, that will likely bring more rain and snow to the region. That’s one reason why I’m putting our chances for a white Christmas only slightly better than 50-50.