Feb 23, 2012 @ 7:39 am

Avalanche Warning Extended

An avalanche warning continues for the mountains of west central Montana.

Good morning, this is Steve Karkanen at the West Central Montana Avalanche Center with an avalanche warning for mountainous locations above 5000 feet in western Montana.

SNOTEL sites this morning report over an inch of SWE and several inches of new heavy snow at locations above the snow line.  Mountain temperatures are in the teens and are expected warm into the 20’s this afternoon.  Winds have diminished but are expected to increase with the next frontal passage.

Weather and Snowpack Analysis

Wind speeds of 0ver 60 mph blasted through the area yesterday with heavy snow.  It’s hard to tell just how much snow accumulated with this event as it was snowing horizontal for much of the day. All mountain locations above 5000 feet were affected by this weather so you can expect to find dangerous wind slabs on leeward terrain.  The southern Bitterroot appears to be the big winner for snowfall.  Lost Trail Ski Area is reporting 36 inches of new storm snow this morning.

This new snow and wind has formed dangerous slabs in most locations especially on leeward terrain.

There are two factors to be concerned with.  The past 24 hours have been relatively warm so the snow has been heavy and wet on top of much colder lighter snow we’ve been enjoying the past few days.  The immediate impact of this is a poor bond between the new and older snow.  This will settle out after a few hours. The bigger problem is a layer of buried surface hoar crystals that have been found in nearly all locations that we’ve been monitoring.  This layer has been the culprit in the close calls and sluff fest last weekend.

Weather Forecast and Avalanche Outlook

With the initial warm temperatures and heavy snowfall the snowpack will quickly settle and begin it’s adjustment to the recent changes.   As temperatures cool down the upper snowpack will slowly get stronger. Expect dangerous avalanche conditions to remain for at least another 24 hours.

Knowing that we have a layer of buried surface hoar with a stronger slab above it will require careful terrain management and a high level of situational awareness.  The danger is obvious right now.  It will get tricky once the weather settles down.

I will update the advisory tomorrow morning.  If you do get out and see avalanche activity, send us a quick email at [email protected].

Avalanche Fatality

There was an avalanche fatality Monday in the Lost Johnny drainage of the South Fork of the Flathead river and near Daisy Pass at Cooke City. Avalanche specialists from Glacier Country Avalanche Center and the Gallatin NF Avalanche Center are investigating these avalanches and will post details once they complete their work.

Dudley posted the following comments Monday and I think it is worth leaving up for this period of high avalanche danger.  I also watched a lot of risky behavior in the Snowbowl sidecountry the past few days. Conditions are a lot different now. The same behavior in these conditions isn’t just risky, it’s dangerous and irresponsible.

Sidecountry Ramblings

It’s time for my mid-winter rant about backcountry (I should say sidecountry) behavior. I was inspired Saturday when I watch three people ski an avalanche chute just outside the Snowbowl boundary together……at the same time. This particular slope had a large skier-triggered avalanche on it this year. I doubt these three riders read the avalanche advisory, so I’m aiming my comments at Snow Bowl parents who may have kids, teenagers or older, ducking the ropes or skiing out-of-bounds. Once you leave the ski area; you’re on your own. The areas just outside the ropes are backcountry. There is no slope management or patrol. You should be prepared to deal with a burial or trauma. It would be a major operation to extract someone from the Rankin Lake basin just outside Snowbowl. Folks are treating this terrain as part of the ski area. It’s not. Do you think people who would ski three at a time down an avalanche chute know when the snow is stable and when it isn’t?

We just had a terrible incident in the sidecountry near Stevens Pass, Washington. Bozeman experienced a major avalanche on Saddle Peak (where everyone hikes) just outside Bridger’s boundary a couple of seasons ago (fortunately no one was hurt). Everyone wants to ski the gnarly terrain; the sidecountry is popular. Have you talked to your kids about drugs, avalanches and skiing out-of-bounds?

Check out this video from the Gallatin Avalanche Center.


This information is the sole responsibility of the Forest Service and does not apply to operating ski areas. The avalanche danger rating expires at midnight tonight but the information can help you make a more informed decision regarding travel in avalanche terrain for the next few days.

Our advisory area includes National Forest System lands in the Bitterroot Mountains from Lost Trail Pass north to Granite Pass, the Rattlesnake Mountains north of Missoula and the Southern Swan and Mission Mountains near Seeley Lake, MT. Avalanche information for the Lookout Pass/St. Regis Basin area is available from the Idaho Panhandle Avalanche Center.