Avalanche Forecast

Issued: Jan 13th, 2022 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Loose Wet and Wind Slabs.

Avalanche Canada wlewis, Avalanche Canada

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High elevations hold dry snow seeing warming for the first time, most concerning in southern areas. Watch for signs of instability, moist surface snow and new natural avalanches. 

Avoid large unsupported slopes, deeply buried weak layers remain a concern. 

Summary

Confidence

Moderate - Uncertainty is due to rapidly fluctuating freezing levels.

Weather Forecast

Freezing levels continue to change rapidly in the wake of the storm, reaching peak elevations on Friday and likely again on Sunday.

THURSDAY NIGHT: Mostly cloudy. Isolated flurries with light southwest winds. Freezing levels range over the region from around 1500m in the north to nearly 2500 m in the south, as elevated warm air moves through. 

FRIDAY: A mix of sun and cloud with moderate to strong southwest winds and a chance of flurries. Freezing levels are once again hard to forecast. Southern areas should expect freezing levels up to 3000 m. Northern areas are likely to stay below 1700 m with a chance of a warm air bubble moving through raising temperatures to 2500m. 

SATURDAY: Freezing levels fall overnight and remain below 1500 m. A mix of sun and cloud with no precipitation expected. Moderate winds from the west. 

SUNDAY: Freezing levels rise around 2000m. A mix of sun and cloud, with increasing southwest winds.

Avalanche Summary

Rain and warm temperatures produced a natural avalanche cycles to size 2.5 at treeline and below. 

At upper elevations, several storm slabs were triggered by skiers and riders to size 2 in steep terrain. Explosive control near Pemberton produced size 3 and one size 4 storm slab, up to 1.5 m deep.

Snowpack Summary

Mixed precipitation and warm temperatures over the last week has created a variety of surface snow conditions. Strong southwest winds have created pockets of dry snow at alpine elevations on north through east facing slopes. 

Precipitation fell as wet snow or rain below 2000m, creating saturated upper snowpack that has now formed a melt freeze crust with moist snow below. 

Two buried weak layers of sugary, faceted grains sit in the middle and lower snowpack, around 50cm deep and 80-200 cm deep. Early Decembers heavy rain and following cold spell formed the deeper layer of facets, that is now most prominent between 1700 and 2100 m. Avalanches on this layer are large, but sporadic and isolated. The most likely place to trigger it would be in thin, rocky snowpack areas. The lower snowpack is well-settled and strong.

Terrain and Travel

  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Be aware of the potential for large avalanches due to the presence of a deep persistent slab.

Problems

Loose Wet

An icon showing Loose Wet

Expect loose wet avalanches to still be possible to trigger, even as the weather improves. Greatest concern is areas of dry snow at higher elevations that will see warm temperatures and sunshine for the first time. 

Watch for terrain that holds heavy and wet surface snow. 

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Wind Slabs

An icon showing Wind Slabs

Pockets of wind affected snow from the strong south-southwest winds may still be reactive to a human trigger. Take care around wind loaded ridgelines and cross loaded features mid slope. 

Expect loading on all aspects, as recent wind directions have varied. 

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Jan 14th, 2022 4:00PM