Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
View on map

Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Start the first day of Spring off on the right foot. Choose lower angled terrain to minimize your chance of triggering a slide on a weak layer buried up to 2 feet below the surface. Slopes that face south, southwest, and west are safer bets. Many slopes have a recently formed crust at or just below the surface.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Decreasing signs of instability associated with a weak layer buried up to 2 feet below the surface continues. The last reported collapses were Thursday, with no avalanche activity since Wednesday. The faceted layer continues strengthening, but limited observations have left uncertainty with the likelihood of a human-triggered slide. Collapsing or whumphing is a sign that you have located this problem. However, not all slopes will provide feedback, and we recommend choosing terrain 30 degrees or less in steepness to limit the chance of ruining your day. 

    (3/15/2022)

    Two layers of near surface facets failed with moderate force. This pit results aligns with reported avalanches and collapses felt by other parties that day. 

    Photo: Blase Reardon

Avalanche Discussion

A weak storm entered the area Saturday night with a mere 1-3 inches of snow reported this morning at mid-elevation weather stations. Westerly winds increased overnight and will continue at a rate capable of transporting snow through the day. We expect thin, small wind slabs to develop at upper elevations through the day. These should be easy to avoid and harmless in size. Saturday's warm temperatures reached 40F or higher at mid-elevation stations and mid-30s at a couple of upper elevation stations. These conditions moistened the snow surface, which subsequently froze last night, limiting snow available for transport.

The Persistent Slab remains on the avalanche problem list. FAC staff is hesitant to remove this problem due to uncertainty regarding the sensitivity of this layer to triggering. We will drop the likelihood of triggering from Possible to Unlikely with more confidence. After which, we will remove this problem from the list. We recommend utilizing terrain wisely and choosing slopes around 30 degrees or less to recreate. If you want to step out into steeper terrain, slopes facing south, southwest, and west have a sun crust that allows safer travel. 

We dropped  Wet Loose from today's problems due to cooler temperatures, crusty conditions, and the snow surface becoming more worked over. 

We only received two observations Saturday, with both parties mentioning moist surface conditions. Our friends with the BNSF avalanche program traveled on southerly aspects and noted moist snow to 7500'. They did notice two crowns of soft slab avalanches which ran earlier in the week in the Ole Creek drainage of Glacier Park. Crowns varied between 200-400 feet wide, with debris large enough to bury a person. A party in the Flathead Range did not notice any signs of instability related to the Persistent Slab problem, but they found moist snow on all aspects up to their high point of 5800 feet. Yesterday's warm temperatures and cloud cover created a greenhouse effect that enabled them to initiate rollerballs on northerly aspects.

The FAC March intern Megan wrote this week's weekly summary of weather, snowpack, and avalanche conditions. You can find this and the weekly summary video in the Conditions Blog tab.

Our final Community Chat is next Tuesday, March 22. In these events, Host Sara Boilen debriefs near-misses. This time she turns the attention to a close call she had earlier this season. Sign up for this virtual, free event here.

Regions covered