Tuesday, December 2, 2008

Washington Pass -- Still Open

AAI just received this email from the Washington DOT:

Dustin and I have been getting calls and e mails asking about the status of the North Cascades – It’s still open.

Before Thanksgiving, the tall (6 to 8,000 foot starting zone) avalanche chutes were about halfway to where they'd need to be to cause a threat and we haven't gotten much more snow (6 to 10,000 feet) over the last week. The forecast doesn't call for much more for the rest of the week, so until we get some "winter" it's going to continue as it has - crews plowing, etc. as needed. Our forecaster says Washington Pass ought to get another 2-3 inches between now and Thursday, which isn't real "threatening”. Here’s the most recent forecast from mid morning:

“Weather as of 1030 Tue was not looking too bad, with Washington pass area flurries and light snow showers. However, some concerns exist. New info suggesting a broken up array of scattered light and short term shower threats sweeping N to S through the area later today into early evening followed by N to S area clearing. A breezy N wind picks up overnight, but a light freeze will occur too. Basically, anything still damp by 9 p.m. is a black ice threat. Basically, if we get the evening showers, then the freeze will follow by midnight. Wed through Fri is dry, with cooler overnight temps and increasing frost.”

Remember that the traditional closure dates are between Thanksgiving week and the 2nd week of December. One substantial storm is really all that is needed to fill those chutes and cause the avalanches that will close it for the season - and it's very likely to happen over the next two or three weeks, but who knows? We have around 14" to 16" of snow on the ground at the summit. A General rule for avalanche danger that closes the highway is 24” to 36” of snow coupled with some additional trigger, i.e. rain or more snow or a big temperature change.

When the season closure comes, it usually happens fast, so if you’re planning a trip, check the pass report and the web page (www.wsdot.wa.gov/traffic/passes/northcascades/) before you leave or call 5-1-1. Washington and Rainy are a thousand feet higher than Stevens and two thousand higher than Snoqualmie, so they often get snow when the others are getting rain.

I’ll send out one of these e mails when the closure comes or if there’s something going on up there that prompts one sooner than that.

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