I always remind myself that occasional soaking winter rains are an essential ingredient of a stable maritime snowpack. If we're going to enjoy the season-long benefits of such a snowpack (freedom from lingering deep instabilities, peace of mind, 10-20 ft snow depths, skiing year-round), we have to endure and even welcome the rain. A few good Pineapple Expresses are an inseparable part of that equation, and very bad things happen if they are missing.
The last La Nina winter (2007-2008), it stayed unusually and consistently cold throughout the winter, without any such heavy soaking winter rains. This caused lingering deep instabilities from an early season crust and hoar layer, which produced the type of fear and unease more typical of continental snowpacks like Colorado. Most notably at Whistler with their season-long battle against destructive avalanches, but also throughout the North Cascades as evidenced by a scary spring climax avalanche cycle after Hwy 20 opened. A good Pineapple Express with heavy soaking rain in early winter could perhaps have destroyed the buried hoar layer which caused all the trouble.
In addition, the snowpack above 7000 ft was very mediocre in 2007-2008 -- despite 947" of snowfall at Paradise (140% of normal), the crevassed glaciers on the upper slopes of Mount Rainier never filled-in properly. The consistently cold temps and absence of major Pineapple Expresses prevented adequate snowfall at those higher elevations. The high-alpine snowpack was average or even below-normal throughout the Cascades, even though it was an epic season at ski area elevations (such as 590" of snowfall at Snoqualmie Pass).
So I'm thankful that it's absolutely dumping snow up high this week. Precip totals at various sites in the Cascades have been 10-16" during the last 4 days since Jan12, so at least 8-12 ft of snow has fallen above 6000-8000 ft. We'll be able to enjoy that snow and that snowpack, soon enough.
And despite no hint of such a shift yet in current 7-10 day forecasts, it is certain that the weather will soon shift to a much colder and wetter pattern. There will be extended periods of sustained snowfall at low snow levels this winter. The effects of the ongoing La Nina will become more evident as we move to mid-winter, since often February and March are months of huge snowfall in such seasons.
Perhaps I'm just too logical, and not overly worried by a few days of rain . . .
