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Archived

Avalanche Forecast

Jan 25th, 2015–Jan 26th, 2015
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
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
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
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Sea To Sky.

The snowpack has been rain-soaked at most elevations, while new wind slabs exist at ridge top. Sunny breaks on Monday may have a destabilizing effect on the snowpack. Pay close attention to conditions that change with elevation and time of day.

Confidence

Fair - Due to the number of field observations

Weather Forecast

A weak ridge will deflect wet pacific moisture streams to the north of the region. The south coast will only receive trace amounts of precipitation throughout the forecast period while high freezing levels will persist. Monday: Mix of sun and cloud with very light rain / Strong southwest winds / Freezing levels at 3100m Tuesday: Overcast skies with very light rain / Moderate southwest winds / Freezing level at 2200m Wednesday: Increased cloud and light snow / Light southwest winds / Freezing levels at 1500m

Avalanche Summary

At the time of publishing this bulletin, observations were extremely limited. That said, I'm sure recent rain sparked a round of loose wet avalanche activity, while wind slab avalanches may have occurred at higher elevations. Although unlikely, deeper persistent avalanches are still a concern in isolated terrain as the snowpack adjusts to recent storm loading and penetration form rain. Any activity on these deeper weaknesses would be very destructive in nature.

Snowpack Summary

Up to 50 cm of settled storm snow has now been saturated by rain up to about 2100m. At the highest elevations, moist snowfall has been shifted into dense wind slabs in lee terrain. New cornice development has also been noted. The older storm snow overlies a hard crust and/or surface hoar layer which formed in January. The bond at this interface will be largely elevation dependant as rain may have penetrated the snowpack enough to dissolve the crust in many areas. At higher elevations where snow has fallen, this interface may still be reactive with the potential for large avalanches.Deeper snowpack weaknesses have become unreactive, but a recent snow profile highlights the stark hardness contrast between a deep persistent weakness and the surrounding snow. Scenarios like this with deeply buried soft snow surrounded by hard snow aren't confidence inspiring because it all hinges on the strength of the overlying slab, which is often volatile and susceptible to significant warming and loading. Especially with very heavy triggers (like a cornice fall) in the wrong spot (like a thin snowpack area).

Avalanche Problems

Loose Wet

Pushy loose wet avalanches remain a concern in steep terrain, especially if the sun comes out on Monday. At higher elevations, rain-soaked snow may increase the chances of waking-up deep persistent weaknesses which formed earlier in the season.
Be cautious of wet sluffing in steep terrain.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid sun exposed slopes, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3

Wind Slabs

Snowfall and extreme southwest winds have created new wind slabs above 2150m. Watch for triggering in the lee of ridgecrests and in gullies. Wind has also shaped new cornices which may be large and fragile.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be cautious as you transition into wind affected terrain.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 4