Turnagain Pass Avalanche Forecast

Due to early season conditions, for both the snowpack and our operations, we will be issuing intermittent snow and avalanche updates until November 17th, as conditions dictate.

BOTTOM LINE
Avalanche conditions will increase this weekend as new snow and strong wind are forecast to spill over from PWS this evening through Sunday. Natural avalanches will be possible and human triggered avalanches likely. Areas of concern are all aspects and slopes over 30 degrees above ~1500′. Likelihood of triggering an avalanche will increase with new snow amount, elevation and in areas with wind loading.

This is a good weekend to dust off and open your avalanche books, replace your beacon batteries and remember how to use your rescue gear. Letting the snow do its thing as well as hopefully cover up a few more rocks may not be the worst of ideas. For anyone that does head into the mountains this weekend, terrain management will be the key for safe backcountry recreation. Keeping slope angles low and watching for obvious clues (i.e., recent avalanches, cracking and collapsing) are things to keep an eye out for.

ANNOUNCEMENTS
Don’t forget to check the photos/observations page for early season information. Also, the calendar page is filling up with free awareness classes and other avalanche education courses offered in our area.

SNOWPACK and AVALANCHE DISCUSSION
This week we have seen a lull in both the weather and avalanche activity, but with new snow and wind on the way for the weekend we can expect that to change. Storm snow instabilities within the new snow, in the form of sluffs and storm slabs, will be likely if the forecasted 10-14″ of snow verifies. These problems should settle out rather quickly, in a day, or at most 2 days.

However, the bigger story, and most concerning, is the new snow load reactivating the old October facets (see image below). It only took 6-10″ of new snow last weekend to create a very touchy slab avalanche problem. With this storm, the facets are not quite as loose as they were a week ago now that they have been buried for 5-6 days. Yet, they are still there and reactive and have the potential to produce larger avalanches this time around. If we get enough snow and wind to get them going that is. The one thing this system does have that the last one didn’t are much stronger winds. These will produce larger wind slabs that form both near (like last weekend) and well off the ridgelines (unlike last weekend).

Snowpack before the Fri-Sun (11/9-11/11) storm sets in. Main concern is faceted layer. Existing surface is generally composed of soft decomposing fragment from last storm.

Any avalanche triggered within the old Oct snow will be around 1-3′ deep and could propagate in areas that are not expected. Remote triggers (for example, triggering an avalanche on top of you from below) are possible. Hence, very conservative route finding is the ticket until this faceted layer gets enough load to either flush out with widespread avalanche activity and/or has time to adjust to the load.

Above cracking is a red light to stick to lower angle slopes, 30 degrees or under (including what is above you).