Contact Us

New Study Finds that “Historic” Missoula Avalanche was Unusual for Many Reasons

Dudley Improta conducting crown profile on March 2
Photo courtesy of the Western Montana Avalanche Center

Today, March 11, the Western Montana Avalanche Center released its preliminary study of the Mt. Jumbo avalanche that plowed into Van Buren Street, killing one woman and trapping three others almost two weeks ago.

Avalanche Specialist Steve Karkanen says that heavy snowfall, cold weather, and strong winds helped to create an event that he described as “historic.”

“It was such an unusual avalanche,” Karkanen said. “The last part of February and the first part of March in most years, that mountain is bare and has no snow on it. The other thing that’s unusual is that it was loaded on the west slope from winds that came out of the east. Typically Mt. Jumbo, on that particular slope, is wind scoured it gets prevailing winds from the west so we typically don’t see much snow that gets loaded on those upper reaches.

Strong winds had been shooting through Hellgate canyon during Friday morning, pushing more snow on top of what was already an extremely abnormal amount of snow for that section of Mt. Jumbo

The strange weather conditions helped make an avalanche that was almost as powerful as it could have possibly been.

It’s never been documented that an avalanche that size has hit the valley floor,” Karkanen. “In the scale of 1 to 5, we are calling that a size 4, which means that it could go bigger at some point, based at the measurements that we have.”

The study showed an average snow depth of about three feet and a total plummet of 2,200 feet from crown to terminus.

Steve Karkanen:

Audio clip: Adobe Flash Player (version 9 or above) is required to play this audio clip. Download the latest version here. You also need to have JavaScript enabled in your browser.


Best of News Talk KGVO

Recommended for You

Best of the Web

Leave a Comment

It appears that you already have an account created within our VIP network of sites on . To keep your personal information safe, we need to verify that it's really you. To activate your account, please confirm your password. When you have confirmed your password, you will be able to log in through Facebook on both sites.

Forgot your password?

*Please note that your prizes and activities will not be shared between programs within our VIP network.

It appears that you already have an account on this site associated with . To connect your existing account just click on the account activation button below. You will maintain your existing VIP profile. After you do this, you will be able to always log in to using your original account information.

*Please note that your prizes and activities will not be shared between programs within our VIP network.

Please fill out the information below to help us provide you a better experience.

(Forgot your password?)

Not a member? Sign up here

Sign up for KGVO Club VIP quickly by connecting your Facebook account. It's just as secure and no password to remember!

Sign up to have exclusive KGVO Club VIP contests, events, coupons, presales, and much more delivered to you for FREE.