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Avalanche Forecast

Dec 29th, 2021–Dec 30th, 2021
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
Below Threshold
The avalanche danger rating below treeline will be below threshold
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
Below Threshold
The avalanche danger rating below treeline will be below threshold
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
Below Threshold
The avalanche danger rating below treeline will be below threshold

Regions: Yukon.

Assess snow surface as you venture out. If you see any signs of instability, choose a low angle slope and pick a line where the snow is deepest. 

Confidence

Moderate - Uncertainty is due to the extreme variability of wind effect on the snowpack.

Weather Forecast

A system, approaching from the north, is passing throughout Yukon Wednesday, with light amounts of snow but strong northerly winds. On Thursday, an arctic ridge of high pressure will re-establish itself, leading to another clear and cold day heading into Friday. The next round of snow is expected Saturday.

WEDNESDAY NIGHT: Lingering flurries / Moderate to strong north winds in the alpine / Low of -20

THURSDAY: Clear / Moderate northwest winds in the alpine / High of -18

FRIDAY: Flurries all day / Strong southwest winds in the alpine / High of -14

SATURDAY: Snow 10 cm / Strong southwest winds in the alpine / High of -12

Avalanche Summary

On Wednesday, the poor visibility restricted observations in the alpine.

No new avalanches have been reported in the last few days. 

If you are out in the mountains, please consider filling out a Mountain Information Network repport.

Snowpack Summary

On Wednesday, the region received about 5 cm of new snow along with southwest winds. This new snow has covered hard surfaces such as sastrugi, old wind slabs or recently scoured slopes in the alpine. 

At treeline, the wind also affected the surface, but pockets of powder can be found. All this snow will get redistributed with the incoming northerly winds, creating cross-loading. 

The lower snowpack is made up of weak sugary snow. An avalanche at this interface is most likely to be triggered in shallow areas or with a large impact like a cornice fall or surface avalanche.

Terrain and Travel

  • Keep your guard up at lower elevations. Wind slab formation has been extensive.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Avalanche Problems

Wind Slabs

Freshly formed wind slabs will likely not bond to the old hard slab and faceted surfaces below. Sensitivity to triggering will be greatest near ridge crests. Shifting winds are prone to form wind slabs on cross-loaded features on various slopes.

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2

Deep Persistent Slabs

Although the crust associated with this layer has largely decomposed, the weak sugary crystals at the base of the snowpack remain. The bridging affect of the wind hammered upper snowpack is making it harder to trigger this layer but now is not the time to become complacent. When managing hard slab on top of facets, try to think in terms of consequences just in case of a surprise. "If I trigger an avalanche here, what are the consequences? Will the avalanche be large? Are there terrain traps?" 

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 2 - 3