Avalanche Forecast

Archived

Apr 18th, 2021–Apr 19th, 2021

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Cariboos.

The best and safest riding will be high north-facing terrain that is free from cornices overhead. Expect avalanche activity on sun-exposed slopes.

Confidence

Moderate - Uncertainty is due to limitations in the field data.

Weather Forecast

A high pressure system brings clear skies and a diurnal melt-freeze cycle.

SUNDAY NIGHT: Clear skies, 30-40 km/h northeast wind, freezing level drops to valley bottom with treeline temperatures dropping to -8 C.

MONDAY: Sunny, light northeast wind, freezing level climbs to 2000 m with treeline temperatures reaching -1 C.

TUESDAY: Sunny, light wind, freezing level climbs to 2200 m with treeline temperatures reaching +1 C.

WEDNESDAY: Sunny with some afternoon clouds, light west wind, freezing level climbs to 2200 m with treeline temperatures around +2 C.

Avalanche Summary

There were reports of widespread size 1-3 wet loose avalanches on sun-exposed slopes on Thursday and Friday (see this MIN report). We have reports of some size 1 wet loose avalanches on Saturday, and suspect more natural wet avalanche activity happened throughout the region over the weekend. Several cornices failed recently. Most did not trigger slabs on slopes below except for a few that triggered size 2 slabs on extreme north facing alpine slopes.

With relatively cooler temperatures on Monday the likelihood of wet avalanches will be reduced, but they will still be possible on sun-exposed slopes.

Snowpack Summary

The snow surface consists of a melt-freeze crust on solar aspects and shaded aspects into the lower alpine, which transitions into moist/wet snow during the day. Dry snow might still be found on northerly aspects in the alpine above roughly 2200 m. While there have been no recent avalanches on buried weak layers, there are a few layers that could potentially be triggered with intense warming or a heavy cornice fall. This includes a few crusts buried over the last month as well as a 150 cm deep facet layer from the mid-February cold snap.

Terrain and Travel

Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
Minimize your exposure time below cornices.
Avoid lingering or regrouping in runout zones.

Problems

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.