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Update on North Cascades Highway Opening


Dan_Miller

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This, just in from WADOT:

 

Hi all,

It happened. The highway closed itself. We're getting slides now - the crew is cleaning up one at Liberty Bell #2 that came down a little while ago. The gates won't actually be closed and locked for another couple of hours since we've got cars parked up there and we've got to find and get those recreational users out. In the meantime, we don't want anybody else up there because we don't know when or where the next slide is going to come. (But we know it will!)

 

Hi all,

The North Cascades Highway is closing at 6 a.m. tomorrow morning unless it closes itself sooner than that. Our avalanche team won't go back in to reassess the conditions until Monday. Right now, they've got a couple dozen avalanche chutes between Diablo and Silver Star that are full and becoming more unstable by the hour as the temperature continues to climb. You'll find this information on our traffic and roads web page and on 5-1-1 and on the North Cascades web page and the information is also going out in a statewide news release from Olympia that will also include avalanche and snow melt and river level issues statewide. The NW Avalanche Center has also issued a back country avalanche warning advising everyone to stay home this weekend. You can stop reading now - that's the news - but to answer some questions you haven't asked yet: "No, avalanche control isn't an option under these conditions on the North Cascades." Here's why: As opposed to the passes that stay open all winter, we don't have any avalanche control facilities in place on SR 20. On Stevens, we've got two M-60 tanks positioned to shoot explosives into the starting zone of the avalanche chutes on the west side of the summit. We've also got a remote radio controlled box of rockets to address some avalanche chutes on the east side of the summit and we've got some snow-cat-usable trails cut above the starting zones of some of the other avalanche chutes that aren't in the range of either the tanks or the remote controlled rockets. (Those are the places where the avalanche crew has to drive up and set off satchel charges by hand. It's what Mike Stanford was doing in the 3 a.m., 100 mph wind video that KING TV ran back on Feb. 10 when we were closed for 54 hours. By the way, that's still available on the WSDOT YouTube site). The only avalanche control tool we've got for the North Cascades is the howitzer which can be mounted on the snow cat's trailer. It works okay to dislodge snow from the lower portions of Liberty Bell's chutes, but most of the other chute's starting zones are out of range and we don't have any snow cat trails cut in because that's Park Service or Forest Service land and for a highway that's closed 5 months a year, it would be pretty hard to justify putting those kinds of permanent "roads" in place. Besides that, we couldn't put them in above a lot of chutes at all, due to the terrain. The North Cascades, besides having more avalanche chutes than anywhere else, also has some of the tallest/longest ones. Delivering ordinance to the top of an avalanche chute that starts between 7 and 9,000 feet isn't feasible. This weekend's situation is highly unusual in that by this time of year, the chutes aren't still full. This spring has been so cold that, while full, the chutes have remained stable. This 30+ degree rise heats up the top layer of snow, making it heavier and creating a slip-plane with the layer below. That's what's happening now and if it slides, what's coming down is going to have the consistency of wet concrete and will probably bring rocks and wood debris with it, so you wouldn't want to be on the highway when that happens. If they find significant slides on Monday - it could take several days to clean up. All we can do is tell you to check the web pages or call 5-1-1. I'll send another e mail Monday when the crew gets back in radio range and tells me what they found and what happens next.

Jeff

 

 

 

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