Jan 17, 2011 @ 6:59 am

January 17, 2011 Avalanche Advisory

January 17th, 2011 Avalanche Advisory

Good morning! This is Steve Karkanen with backcountry avalanche information for Monday, January 17, 2011.  It’s Martin Luther King Jr. Day.

Current Avalanche Danger

Because of continued snowfall and high wind above 6000 feet, the avalanche danger is CONSIDERABLE on all wind loaded terrain steeper than 30 degrees. Dangerous avalanche conditions exist on steep wind loaded slopes. Natural avalanches are possible, human-triggered avalanches are likely. Careful snowpack evaluation, cautious route-finding and conservative decision making is essential for safe travel in avalanche terrain.

All other slopes and at elevations below 6000 feet have a MODERATE avalanche danger. Natural avalanches are unlikely but human triggered avalanches are still possible.

Weather and Snowpack Analysis

The higher mountains continue to receive abundant snowfall coupled with high winds from the W-NW this morning. The amounts of snow and rain have dropped off since Saturday and has allowed the snowpack to settle quickly and adjust to the added weight.

At 7800 feet in the Rattlesnake our stability tests were showing the new snow to be much stronger and is beginning to bond well to the older snow. This heavy dense snow initially came in on a much colder, drier layer and was the cause of our concern about stability Friday. This layer was not failing easily in any of our tests and the now deeply buried surface hoar continues to strengthen.

The rain line was up to about 6000 feet Sunday but this will begin to drop after today. Areas that have received rain earlier have mostly stabilized but if it starts raining in places that have not seen rain on snow the avalanche danger will rise quickly.

Weather Forecast and Avalanche Outlook

The upper level flow will become northwesterly the next 48 hours with continued snow showers and gradual cooling. Snow levels should reach the valley floors by Tuesday.

Expect the avalanche danger to continue to improve as we begin to cool down. Areas of greatest concern will be anything open and wind loaded near the ridges.

The next advisory will be issued on January 21, 2011.

Upcoming Events

On January 26th, Skip Horner, a well-known mountaineer who was the first to lead guided trips to the legendary Seven Summits, will be giving a fascinating talk and slide show to benefit

This show is at the Trail Head, 221 East Front and starts at 7pm.

We have scheduled a Level 2 Avalanche class February 15-18.  This course is in response to the many requests we receive every year to provide this level of training in Missoula.  To date, only 3 people have registered and we need 12 to make it happen.  More information can be found on the American Avalanche Institute website.  This is a great opportunity for those of you wanting to broaden your avalanche education.  Don’t miss it!


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.