Wednesday, January 13, 2010
El Nino, Snow, and the Olympics
There have been a number of calls today about the influence of the recent warm weather on the snowpack, and many were about the upcoming winter games in British Columbia. Big news today: Cypress Mountain near Vancouver, the future venue for freestyle skiing and snowboarding, was closed to protect its rapidly thinning snowpack. An observing site on the mountain at 3100 ft went from 43 inches of snow on 1 January down to 27 inches today. Not good. But I suspect they will be ok, due to the aggressive snow mining and snow making operations, and the inevitability that there will be some cooler periods when they can build up the snow pack both naturally and artificially. Those Canadians are determined to pull this off and they probably will. And they have a very experienced team of weather forecasters and lots of additional weather gear.
The problem of course is El Nino. As shown in the figure below, the tropical Pacific is much warmer than normal, and the second figure shows the variation of central Pacific surface temperature ( the famous Nino 3.4 zone) is roughly 1.5C above normal. Both of these figures suggest a moderate El Nino right now and this is NOT going to change during the next few months.
As I have explained before El Ninos are associated with above normal temperatures and below normal precip after January 1. And substantially lower than normal spring snowpacks. Now, lets be careful...this is a correlation, not an exact prediction. El Nino winters tend to have less snow, but some have had more than normal. Now the problem we have is that we are starting the El Nino season with a below normal snowpack (see the latest values in graphic below). Lots of the NW is 65-80% of normal. And the latest long-term prediction of the Climate Prediction Center reflects the El Nino correlation (see graphics below). Warmer than normal from Washington to the upper Plains. Wetter and cooler than normal along the southern tier of states.
So let me be blunt: I wouldn't run out and buy a season pass at Snoqualmie Summit right now...but you probably suspected that.
We are in a break right now, but tomorrow (Thursday) strong SW flow will redevelop and heavy rain will again hit the SW sides of the Olympics, the mountains of Vancouver Island, and the N. Cascades. Snow level will rise. Winds will pick up again over NW Washington and along the coast. AGAIN! And the current model runs showing this repeated several times during the next week. The general pattern is pretty locked down, so get used to it.
Here is a marvelous graphic of the integrated moisture content of the atmosphere tomorrow at 4 PM. A narrow plume of moisture headed towards us...a.k.a. an atmospheric river. But more on that some other time.
Posted by Cliff Mass at 8:35 PM