Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Monday, April 1st at 7:00 a.m. Today’s forecast is sponsored by Bridger Bowl, Cooke City Motorsports and Advanced Innovation. This forecast does not apply to operating ski areas.
Yesterday morning the mountains got 1-3” of new snow. Yesterday the wind was from the northeast-east at 5-15 mph, and overnight wind shifted to the north-northwest at 5-15 mph with gusts of 20-40 mph. This morning temperatures are teens to low 20s F. Today, under mostly sunny skies, temperatures will reach mid to high 30s F, and wind will be northerly at 5-20 mph. The next couple days will be warmer with daytime temperatures reaching 40s and 50s F before a return to wetter and cooler weather at the end of the week.
All Regions
Sunshine and temperatures above freezing will make wet snow avalanches the main concern. Additionally, a person can still trigger slabs of recent new snow or very large avalanches that break many feet deep on weak layers near the bottom of the snowpack.
On slopes that receive direct sunshine, the recent snow will quickly become wet and easily slide. Loose wet avalanches are likely, and have potential to become large with up to a foot of soft recent snow to entrain. Stay off and out from below steep slopes that receive direct sunshine, especially later in the day. A snow surface that is moist or wet indicates wet snow stability is deteriorating, and it is time to find shadier or low angle slopes.
A person can also trigger dry slab avalanches involving last week’s snow, especially where it was drifted into thicker slabs (photo, photo). On Saturday in the Lionhead area near West Yellowstone a pow surfer (snowboarder without bindings) triggered and was partially buried in an avalanche that appeared to break below last week’s snow (photo). The recent snow buried a new weak layer, as we saw in Taylor Fork last week (video), which might make recently formed drifts or slabs of new snow unstable longer than usual. Before riding steep slopes you should dig down a couple feet to look for weak layers and test for instability.
Very large avalanches that break on weak layers near the bottom of the snowpack have become less likely compared to earlier in the winter, but have the largest consequences and require thoughtful terrain selection to avoid. A couple recent 2-6’ deep avalanches in Hyalite, on Flanders Mtn. (photos, video) and Mt. Blackmore (photos), show the lingering possibility to trigger one of these monsters. These could also be triggered from the weight of a smaller avalanche or cornice falls which are possible with today’s sun and warm temperatures. If you ride or cross steep slopes, choose slopes that are not heavily wind-loaded and without trees, rocks, cliffs or gullies that would increase the chances of being injured or killed if you were caught in a slide.
The avalanche danger is MODERATE this morning, and will rise to CONSIDERABLE this afternoon as wet snow avalanches become likely.
If you get out please submit an observation. It does not need to be technical. Did you see any avalanches? How much snow is on the ground? Was the wind moving snow? Simple observations are incredibly valuable. You can also contact us by email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).
Upcoming Avalanche Education and Events
Hyalite Road Closure: Hyalite road is closed to ALL MOTORIZED VEHICLES until the morning of May 16. This is a regular annual road closure to reduce road damage during the spring thaw. Bicycle and foot traffic are allowed. Contact the Bozeman FS Ranger District for more info.
Events and Education Calendar.
Loss in the Outdoors is a support group for those affected by loss and grief related to outdoor pursuits. Check out the link for more information.
If you have a few minutes, take a survey on how you interpret avalanche forecast information in hopes of improving avalanche forecasting methods.