Archived

Avalanche Forecast

Jan 2nd, 2018–Jan 3rd, 2018

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Glacier.

There is lots of uncertainty what's going to happen today as temperatures rise. Slab properties will change over the December 15th persistent weak layer, and a skier or rider could be the trigger needed to start a slab avalanche.

Weather Forecast

The main story for today and into the near future is the temperature inversion. Steep solar aspects in the alpine will see the most effect, while valley bottoms will stay cold and continue to facet. The inversion is set to last until Friday, when a low-pressure system slides in from the Pacific, pushing out the high pressure.

Snowpack Summary

The snowpack is quite a mixed bag of layering depending on Aspect and Elevation. The Dec 15th PWL (most prominent at TL) is the main layer on our radar, and we're still waiting for it to really produce a decent cycle. We've observed some failures of this layer "cracking" giving the snowpack a rippled effect, but still not failing as an avalanche.

Avalanche Summary

There have been no significant avalanches observed or reported in the last few days in Glacier National Park, with many of the standard lines been skied. Our Neighbors have seen more avalanches of late, due to either more load and slab formation or a shallower snowpack resulting in poor bonding between layers. We may see a change today!

Confidence

Intensity of incoming weather systems is uncertain

Avalanche Problems

Persistent Slabs

The December 15 surface hoar layer is widespread around treeline and buried 60cm. Cold temps have kept the slab from gaining cohesion, but today's warming trend may make it more reactive especially on steep unsupported terrain.

Watch for signs of instability such as whumpfing, or cracking. Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3

Loose Dry

We may see a natural loose dry cycle on steep solar aspects today, with solar radiation and an inversion. The combination of a loose sluff, plus a skier or rider could be the load for a step-down slab avalanche to the Dec 15th persistent weak layer.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Avoid thin, rocky or unsupported slopes.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2