Avalanche Forecast

Archived

Mar 17th, 2020–Mar 18th, 2020

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Cariboos.

A ridge of high pressure has set in for the forecast period. Expect to see mainly sunny skies. Minimize exposure to steep slopes facing the sun during the hottest part of the day.

Confidence

High - Confidence is due to a stable weather pattern; little change is expected for several days.

Weather Forecast

TUESDAY Night: Mostly clear, light northwest wind, alpine temperature -8 C.

WEDNESDAY: Mix of sun and cloud, light northwest wind, alpine temperature -7 C, freezing level 1200 m.

THURSDAY: Mix of sun and cloud, light to moderate west wind, alpine temperature -5 C, freezing level 1400 m.

FRIDAY: Mix of sun and cloud, light northwest wind, alpine temperature -4 C, freezing level 1500 m.

Avalanche Summary

Most recent avalanche activity has been reported as natural loose wet and dry avalanches to size 1.5 and 2 running on steep sun exposed slopes in the alpine. There have also been reports of cornices failing in the alpine on northerly aspects to size 2.5.

Snowpack Summary

Wind from the northeast over the weekend has redistributed snow and formed wind slabs at all elevations.

A weak layer of surface hoar buried at the end of February may be found 50-100 cm deep. Sheltered north, northeast, and east facing slopes near treeline are the most likely locations to find this layer. Reports indicate that this layer may be absent in the northern tip of the region.

There is a low likelihood of triggering an avalanche on this layer, but the consequences of doing so would be high. Read more about surface hoar on our forecaster blog.

Terrain and Travel

If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
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 buried surface hoar.
Cornices become weak with daytime heating.

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.

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.