Posted:
Nov 24, 2020 @ 9:48 am

This is Jeff Carty with an early season snowpack update on Tuesday, November 24th, 2020.

As everyone who has been out skiing and riding knows, there is an above-average snowpack above 7000’. In contrast to last year, the snow arrived early, built good depth, and has consolidated well.

This is a good foundation to build on for the winter, and we will most likely avoid the faceting issues we saw last year. Windslab is the main issue currently, especially on higher elevation slopes over 35º. With moderate to strong winds forecasted throughout the week and some fresh snow in the forecast, expect these wind slabs to get touchier and more destructive.

Keep in mind that this time of year, the areas that are best to ride are the most likely to slide. As we look for slopes with enough snow to cover rocks and early season hazards, we often gravitate to wind loaded areas. Be aware of stiff, hollow sounding snow, fat pillows, and shooting cracks. Check your slope angles and stick to slopes under 35º if in doubt.

Below 7000’, snow depths diminish rapidly, and early season hazards are abundant. Below 6000’, there is minimal to no snowpack. The main hazard here is trees, rocks, or whatever is lurking just below the surface. Take care! There has already been a death this year in Alberta due to shallow snow, rocks, and a head injury.

This year could be an interesting one with COVID-19. Backcountry use spiked last spring, numbers seem to be up this early season, and backcountry gear sales are skyrocketing. We expect to see more people in the backcountry. While there is enough space in the backcountry for all of us, this could put extra pressure on roadheads where parking is often limited already. Please be respectful of others and private landowners.

Increased numbers in the backcountry mean an increased likelihood of accidents, and COVID-19 means higher risk to rescuers and everyone involved. Now is a good time to dial back our risk tolerance and provide larger margins of error to keep everyone safe.

If you are new to the backcountry, please get the training required to be safe and avoid avalanches. If you are a seasoned backcountry traveler, remember that techniques change with new research, and our skills can get rusty over time. It’s wise to update and practice yearly. Check out our education page for information on the courses we offer.

We need your observations! Please submit them on our public observation page. Everything you send in helps us assess conditions throughout the forecast area. A picture speaks a thousand words.

Lastly, look for regular advisories to begin on December 1st, 2020.

Ski and ride safe.

READ FULL ADVISORY  

Problem 1 - Wind Slab

  • TYPE

    wind-slabs

    Wind Slabs

    Release of a cohesive layer of snow (a slab) formed by the wind.  Wind typically erodes snow from the upwind sides of terrain features and deposits snow on the downwind side.  Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

  • SIZE

    3-4

    1-2 (Small-Large)

    The potential size of avalanche resulting from this problem.

  • LIKELIHOOD

    Likelihood-3

    Possible

    The likelihood of an avalanche resulting from this problem.

Wind loaded slopes will have the greatest potential for avalanches. New and blowing snow will create the potential for small avalanches, primarily at upper elevations.

FORECAST & OUTLOOK

Here is a link to the forecast.

 

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.