Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Mar 5th, 2023–Mar 6th, 2023

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Below Threshold.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Below Threshold.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Below Threshold.

Regions

Yukon, Tutshi, Wheaton, White Pass East, White Pass West.

Be suspicious of areas where the wind is actively depositing snow. Strong wind can make windslabs in less common areas, like part way down large slopes, and on steep cut banks.

Confidence

Moderate

Avalanche Summary

On Saturday, low elevation wind slabs were reactive to rider triggers. A size 1 was reported triggered by a sled in a MIN report from Fraser.

On Friday, our field team observed natural wind slab avalanches up to size 2 and loose snow sluffing from steep alpine terrain around the White Pass.

Also during the storm last week, a natural avalanche cycle up to size 3 was observed from the highway in the inland areas around Paddy peak. We suspect that some of these may include step-downs to buried weak layers.

Snowpack Summary

Recent snow has been stiffened at the surface in exposed areas and transported into wind slabs by strong outflow wind at all exposed elevations.

The mid snowpack is generally hard with a couple of crusts buried 60+ cm and 100+ cm deep, these have been problematic on north to east aspects as high as 1700 m, where they are covered in an overlying layer of weak surface hoar crystals. In inland areas these weak layers are closer to the surface and are easier to trigger.

At the base of the snowpack large sugary crystals persist.

Weather Summary

Sunday night

Clear. Moderate to strong northerly wind. Alpine temperature -16 ºC.

Monday

Increasing cloud. Snow beginning in the afternoon, up to 5 cm. Low elevation wind easing, upper level wind strong northerly. Alpine temperature -18 ºC warming rapidly in the afternoon to -10 ºC.

Tuesday

A mix of sun and cloud. Strong northerly outflow wind. Alpine high -15 ºC in the morning, cooling through the day.

Wednesday

A mix of sun and cloud. Northerly outflow wind easing. Alpine high -22 ºC.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Seek out sheltered terrain where new snow hasn't been wind-affected.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Problems

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.