Wednesday, March 8, 2017

Next round of weather could increase avalanche danger and lead to mountain pass closures

By Meagan Lott

It's been a long winter and it doesn't look like the end is in sight, at least not for the next couple of days in the mountains.

The weather forecast is calling for up to eight inches of snow to fall in the mountains by Wednesday night with another seven inches by Thursday morning. By Thursday afternoon, the snow is expected to switch to a rain and snow mix then to a heavy, wet snow by Thursday night into Friday morning.

While warmer weather is usually welcome news this time of year, in this case, it presents a challenge. These conditions can cause the snow pack to become unstable and increase the risk of avalanches. The last time we saw these kind of conditions was in early February when avalanche danger kept all three mountain passes in the state – I-90 Snoqualmie, US 2 Stevens and US 12 White passes – closed for more than 24 hours.
Drivers over our mountain passes should be prepared for avalanche control
closures over the next few days as heavy snow turns into heavy rain.
While we can't control the weather, we can be proactive by helping you with your travel plans. And for this weekend, that includes a lot of students from Washington State University who may be returning to the west side of the state for Spring Break.

If Mother Nature follows through with the next round of snow and rain, there is a very good chance we will have to close one, two or all three of the mountain passes due to the risk of natural avalanches, snow slides and to conduct avalanche control work.
Heavy snow followed by warmer temperatures and heavy rain could present
significant avalanche danger in our mountain passes over the next few days.

Whenever we close a mountain pass the most common question we get is "How long will it be closed?" That's a very tough question to answer. If it's for avalanche control, it's usually between 20 minutes and 2 hours depending on how much snow and debris comes down. But a closure due to avalanche danger is a wildcard. Until that danger subsides, we often can't even send our crews into the area to do avalanche control or cleanup, for their safety. In those cases, even coming up with estimates for length of closure is tough. The true answer is, "Not until it's safe for everyone to be in the area."

So how can you prepare? If you can, try to postpone your trip over the mountains until later this weekend. If not, try to go before Thursday afternoon. Be sure to check our mountain passes web page for updates on conditions and traction requirements. And be prepared in case you find yourself stuck in a closure. Closing a pass is never something we take lightly but safety is always our top concern so please be aware of what may be on the  horizon and be sure you and your vehicle are ready just in case.

1 comment:

Unknown said...

Thank you for sharing the inside view on the challenges that WSDot faces. It makes me want to be a little more patient!!!

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