This is an archived advisory related to a fatal avalanche on Mar 1, 2024

Idaho Panhandle Avalanche Center, US Forest Service
Backcountry Avalanche Forecast
Selkirks & Cabinets

Avalanche Warning
ISSUED Friday, March 1, 2024 - 9:00AM EXPIRES Saturday, March 2, 2024 - 7:00AM

Issued: Friday, March 1, 2024 - 7:00AM
Expires: Saturday, March 2, 2024 - 7:00AM
Author: Krmpotich / Thompson

THE BOTTOM LINE

Dangerous avalanche conditions are present due to intense winds and wet storms. Avoid being in avalanche terrain. Natural avalanches have been observed. Human-triggered avalanches are very likely. 

Avalanche Forecast

Avalanche Danger
Friday, March 1, 2024
High (4) - All elevations

Avalanche Problems (2)

Problem #1: Wind Slab
Aspect/Elevation: W-N-E near and above treeline
Likelihood: Very Likely
Size: Large (D2)

Strong south winds are quickly building touchy slabs and cornices near ridgetops. Large Wind Slab avalanches are very likely. Wind transport has been fast enough to reload slopes that have already avalanched. 

Avoid being in, near, or underneath all avalanche terrain. Remain patient in very low angle simple terrain, or simply decide to not go out into the mountains backcountry while instability is highest.

Problem #2: Storm Slab

Aspect/Elevation: All aspects and elevatons
Likelihood: Likely
Size: Large (D2)

Storm snow is pilling up and forming cohesive slabs. A ton of new snow (about 3 feet or 3” of snow water equivalent) has fallen in the last 2 days in the mountains. As you move up in elevation, new snow totals get deeper and deeper. Storm slabs are widespread and are avalanching naturally in small terrain features. 

Forecast Discussion

The Selkirk and Cabinet Mountains have received over 3 feet of snow at elevations above 4500 feet since the storm started on Tuesday night. Below 4500 feet, a mix of rain and snow is present. Wind speeds during this storm have ranged from moderated to strong (10-50 mph), primarily coming out of the southwest. Open slopes have experienced significant cross-loading, resulting in varied snow conditions – from areas stripped of snow with a surface rain crust to slopes completely filled with multiple feet of snow. Notably, cornices on North-facing slopes have substantially grown throughout the storm.

Limited visibility has made observations challenging, but Schweitzer Ski Patrol has actively triggered many avalanches using explosives and ski cuts. The storm's snowfall has exhibited various densities, and the combination of wind and temperature fluctuations has introduced multiple instabilities in the new snow. Recently, we encountered firm snow atop soft snow, and the current round of snowfall, with reduced density, could add another layer of complexity. Although these different storm layers typically heal quickly, the interfaces are presently prone to failure.

Weather forecasts and models indicate that snowfall will persist through the weekend and into the next week, with the Selkirk and Cabinets potentially receiving another 10-20 inches of snow by Sunday. Anticipate a slight cooling in temperatures, leading to lighter snow density into the weekend, while winds are forecasted to range from 15-30 mph, continuing to blow from the southwest.

Weather Forecast

For Friday March 1st, snowfall rates will decline with modest accumulations expected at higher elevations in the range of 1-3". Winds will decrease relative to the past few days but expected to continue blowing out of the south and southwest with gusts into the upper 20's. On Saturday we will see another round of moisture hit the mountains that will bring 4-9" on new snow and appears to favor the West Cabinets.