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Avalanche Forecast

Dec 7th, 2019–Dec 8th, 2019
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Lizard-Flathead.

If we get less than 15 cm Saturday night into Sunday; treat the alpine as CONSIDERABLE. Clear skies and pow are rad, but we all need to keep the terrain choices conservative Sunday, it's a long winter and we're just getting to know our young snowpack.

Confidence

Low - Uncertainty is due to the limited number of field observations. Forecast snowfall amounts are uncertain.

Weather Forecast

The weather pattern is setting up to offer the Lizard Range a decent amount of storm snow Saturday night into Sunday morning before an Arctic Ridge takes over for the work week.

SATURDAY NIGHT: Freezing level at valley bottom, moderate to strong southwest wind, 5 to 20+ cm of snow expected.

SUNDAY: Overcast at dawn, clearing by mid-morning, light to moderate northwest wind, a few cm of snow possible.

MONDAY: Broken cloud cover, freezing level at valley bottom, light variable wind, no significant precipitation expected.

TUESDAY: Broken cloud cover, freezing level at valley bottom, light southwest wind at valley bottom, potentially strong northwest wind at ridgetop, no significant precipitation expected.

Avalanche Summary

Recent reported avalanche activity is limited. Explosive control work in the Lizard Range Friday produced a size 2 avalanche which failed on the mid-November crust on an east/southeast aspect at 1900 m.  

Snowpack Summary

As of Saturday afternoon the series of storms has produced 20 cm over the last 48 hours bringing the 7 Day total to just over 40 cm.  

Crust layers from November and October can still be found deeper in the snowpack. As the load on these weak layers increases with new snow, they could become more reactive.

Snowpack depths are highly variable this early in the season with amounts ranging between 50-100 cm at higher elevations and tapering rapidly below treeline.

Avalanche Problems

Storm Slabs

15+ more cm of snow Saturday night into Sunday is likely to induce a natural avalanche cycle, at least in the storm snow. This is a challenging time for backcountry travel because thin snow cover down low has a tendency to push us into the Alpine where the hazard and likelihood of triggering storm slab avalanches is greatest Sunday.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2.5