Apr 11, 2010 @ 12:00 am

Late Season Information

This is Steve Karkanen from the West Central Montana Avalanche Center with a few late season observations and safety information for April, 2010.

Although we issued our last avalanche advisory on April 2, weather conditions of the past several days more closely resemble conditions we expect in mid-February, not mid-April. We received a report of a skier triggered slab avalanche on the NE-E aspect of St. Joe Peak in the Bitterroot last week (4/4/10). The person reported that it failed on a faceted layer deep within the snowpack.

Much of the mountain snowpack in western Montana is at 60% of normal but temperatures are staying cool allowing some great late season skiing and riding for those willing to work a bit harder and maybe ride over a bit more dirt than usual to get to the goods.

Some things to consider when you do get out there. Don’t forget to take all your avalanche safety equipment with you and have your transceiver strapped on and turned on. I know of at least two examples this year of very experienced people either not having their transceiver on them or leaving it at home then being caught in an avalanche. In one case, fortune kept an individual on the snow surface and alive. The other case is much more tragic and we may never know why a transceiver was not strapped on. It would not have made any difference in the outcome here as the person was skiing solo when caught.

Snow conditions in April and early May can be epic in the Northern Rockies. Avalanche conditions can be just as memorable so take the time to check the stability of the slope you want to recreate on. The north or more shaded slopes this year are still holding the nasty buried facets responsible for a fatality and many close calls in our area the past few weeks. That layer is now two and a half months old but given the right conditions, it can fail with big consequences.

The most common avalanche condition will be new snow melting and sliding as the sun hits it or when temperatures rise above freezing. Be very careful around cornices, they grew pretty big during the last storm and will be more sensitive than the cornices that developed earlier this year.

If you get out and find conditions worthy of passing along, please do contact us at [email protected] or call our office number at 406-530-9766 or 406-329-3752.
For more general information about backcountry conditions or questions about access and travel, please contact the local Forest Service Ranger District Office in the area where you plan to recreate.

Have a safe fun summer!


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.