Apr 4, 2014 @ 4:05 pm

April 4, 2014 Avalanche Information

Hello! This is Steve Karkanen at the West Central Montana Avalanche Center with an avalanche information update for Friday, April 4, 2014.

We are no longer issuing avalanche danger ratings for the 2013/14 season.

Mountain temperatures this week have ranged from the mid thirties and forties in the afternoons to the mid twenties overnight. The heavy snowfall many areas received last weekend has now been through a few melt-freeze cycles and is most likely as hard as concrete early in the day then becoming soft as the day progresses.

Aspects exposed to the sun are producing point release wet avalanches as the snow warms up in the afternoons and a few locations on the granite faces in the Bitterroot Mountains have seen much deeper avalanche activity during prolonged warm periods or during rain.


April Snow Safety Considerations

When it snows:

Assess how well storm snow bonds to the old snow surface.  New snow last weekend was failing easily on a hard crust that formed during the warmer temperatures prior to the storm. Many natural avalanches were observed in the southern Swan and Mission mountains last weekend with the new snow failing easily on this interface.

Fresh wind slabs can be very sensitive during and for a few days after a storm.

Cornices are scary looking for a good reason.  Steer clear of them, they have a nasty reputation for breaking further back when they get this big.

When it warms up:

Wet, loose snow avalanches can entrain enough snow to cause step down slab avalanches that tend to be more destructive (unsurvivable).

Wet slab avalanches are a troublesome beast so when mountain temperatures remain above freezing for a night or two, don’t trust anything steep and loaded.

Cornices are not only scaring looking, they also fail easily all by themselves when it warms up. A large cornice dropping onto a big slope can trigger large slab avalanches, wet and dry, this time of year.

Overall stability conditions are easily monitored by paying attention to the aspect and air temperature.  Move to more shaded northerly terrain as the temperature warms above freezing. Avoid being on or under open steep terrain when you see pinwheels or small point release avalanches peeling off steeper terrain.  When you start punching through to your boot tops move to cooler/shaded areas where the snow is more stable.

When the ski areas are closed, the in-bounds terrain is backcountry terrain and you must plan accordingly.  If you are unsure about a resort’s uphill policy, or where to access public land from a resort, the time-honored Montana tradition is to ask the landowner.

We will continue posting public observations as we receive them. You can submit an observation directly from our website.


Avalanche Center Support for the Future

An online petition asking the Forest Service for renewed commitment of the West Central Montana Avalanche Center is available here:

This has been a difficult season for many people in western Montana and many of you have stepped up to help the friends and families of the people affected by the Mount Jumbo and Altoona Ridge Avalanches.  You have also gone above and beyond with the support you’ve shown for the work the avalanche center does.

The many benefits sponsored by the local breweries and businesses have been well attended and by all accounts, very successful at raising much of the funding needed to produce a 2 day a week avalanche advisory as well as the many avalanche classes taught in the local area.

The relationship between the West Central Montana Avalanche Center and can sometimes be confusing. is a 501(3)(c) non-profit that supports the Avalanche Center through a cost-share agreement with Lolo National Forest.

Although the Forest Service is responsible for the avalanche advisories; the non-profit provides all operating funds, including salaries for the forecasters (avalanche specialists) and educators. Funds are raised primarily through the efforts of the folks on the Board of Directors. They are Mark Waller (Chair), Steve Porcella, Spencer Bradford, Ross Peterson, Russ Read, Mike Birnbaum, Justin Metcalf, Zachary Millar, Mark Fricke and Katy-Robin Garton.

Without their hard work it would be difficult, if not impossible, for the Center or the advisories to exist. The community is fortunate to have these folks volunteering their time.

Thanks to all of you for making this program a success!




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.