Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, March 25 at 7:30 a.m. Yellowstone Club Community Foundation in partnership with the Friends of the Avalanche Center sponsors today’s advisory. This advisory does not apply to operating ski areas.
A small weather disturbance dropped an inch of new snow in Cooke City last night while everywhere else had clear skies. Mountain temperatures are in the low twenties with ridgetop winds blowing 15-20 mph from the west to southwest. Today will be mostly sunny and temperatures will rise to forty degrees with winds remaining the same. Clouds will form late tonight and snowfall will begin early tomorrow morning and drop 1-2 inches in the southern mountains.
Bridger Range Gallatin Range Madison Range
Lionhead area near West Yellowstone Cooke City
All I wanted was a straight answer from the snowpack, but that was clearly asking too much. Yesterday morning as I drove to the Bridger Range I had a simple question, “Is the danger Low on all slopes?” It sure seemed like we were trending that way, but the answer was not that simple. One of my pits was on a steep, south-facing slope leading into the Hourglass chute north of Bridger Bowl (photo). The snowpack was six feet deep and as I was digging I sunk to the ground in depth hoar. A compression test failed with moderate force one foot off the ground on this layer, yet my extended column test (ECT) did not—conflicting results. This season figuring out stability is extra tricky because the snow sometimes breaks easier and deeper than we think. Just gently placing my shovel blade behind the ECT caused the block to easily pop off which further convinced me to not tempt the avalanche dragon. The danger was not Low on this slope. Even if you do not understand stability test results, the message is the same: Many slopes have weak snow near the ground and even though the chances of triggering an avalanche are diminishing, the consequences remain severe. So what did we do? I skinned out of my snowpit and my partner and I went to a different slope with a different snow structure to descend.
This message resonates throughout our entire advisory region. Deep slab avalanches are scary because they are difficult to predict. Avoidance is the best tactic. Avoid steep, thinner, rocky areas of a slope which are trigger points for these avalanches and be aware that tracks on a slope are not indicative of stability, especially when dealing with this type of avalanche problem. Mark wrote a short article on deep slabs and we also made a video outlining why they are so dangerous and what to look out for.
Today, human triggered avalanches are possible on slopes steep than 35 degrees which have a MODERATE avalanche danger. Less steep slopes have a LOW avalanche danger.
I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.
Our last daily avalanche advisory will be Sunday, April 6th. If conditions warrant we will issue intermittent advisories the following week.