Avalanche Forecast

Archived

Mar 24th, 2025–Mar 25th, 2025

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Lizard-Flathead, Flathead, Lizard.

Rising temperatures are creating very dangerous avalanche conditions and terrible riding quality. No reason to go near avalanche terrain.

Confidence

Moderate

Avalanche Summary

Several natural and artificially triggered size 1 to 2 storm slab avalanches have occurred daily since Thursday.

This rider-triggered slab from Saturday looks like it could have run on a persistent weak layer in the upper snowpack. Glad everyone got out okay!

Looking forward, we can expect an uptick in these types of avalanche activity as temperatures rise.

Snowpack Summary

The upper snowpack remains warm and wet after having been soaked by rain at most elevations.

A melt-freeze crust is found around 60 cm deep, except on high-elevation north and east-facing slopes.

A surface hoar or facet layer from late January is buried 100 to 150 cm deep on north and east aspects at treeline and above. This may re-emerge as a persistent slab problem with warming this week.

Weather Summary

Monday night

Cloudy with 1-5 cm of snow above 2000 m, light rain below. 30 to 50 km/h southwest ridgetop winds. Treeline temperature 0 °C. Freezing level 2200 m.

Tuesday

Flurries bringing a trace of snow. 20 to 30 km/h southwest ridgetop winds. Treeline temperature +5 °C. Freezing level rising to 2600 m.

Wednesday

Sunny. 10 to 20 km/h south ridgetop winds. Treeline temperature +10 °C. Freezing level rising to 3500 m.

Thursday

Flurries. 30 to 40 km/h southwest ridgetop winds. Treeline temperature +1 °C. Freezing level falling to 2000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be aware of the potential for large avalanches due to buried weak layers.
Avoid exposure to overhead avalanche terrain; avalanches may run surprisingly far.
Only the most simple non-avalanche terrain with no overhead hazard is appropriate at this time.

Problems

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.