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 16th, 2020–Mar 17th, 2020

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.

Regions

Kootenay Boundary.

Daytime warming could weaken the snowpack. Be especially cautious underneath steep sun exposed slopes and around rock outcrops.

Confidence

High - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

A ridge of high pressure brings clear dry conditions for the week.

MONDAY NIGHT: Clear skies, light northwest wind, freezing level drops to valley bottom and alpine temperatures drop to -10 C.

TUESDAY: Mostly sunny, light northeast wind, freezing level climbs to 1800 m in the afternoon with alpine temperatures reaching -1 C.

WEDNESDAY: Mix of sun and cloud, light northeast wind, freezing level climbs to 1500 m in the afternoon with alpine temperatures reaching -3 C.

THURSDAY: Mix of sun and cloud, light east wind, freezing level climbs to 1000 m with alpine temperatures reaching -4 C.

Avalanche Summary

Many wind slab avalanches were triggered on Saturday and Sunday, especially on south aspects and at treeline and alpine elevations. Most were rated as small (size 1-1.5), but a few larger (size 2.5-3) slabs were observed on southeast alpine slopes.

Avalanche activity on the surface hoar layer described in the Persistent Slab problem is starting to quiet down. Over the past two weeks, small to large (size 1-2) avalanches have released on this surface hoar layer. They have most often released between 1800 and 2300 m on northwest to east aspects.

Looking forward, daytime warming will weaken the snowpack and create the potential for loose avalanches on steep sun-exposed slopes and increase the likelihood of wind and persistent slab avalanches.

Snowpack Summary

Each day rising freezing levels and the sun will potentially weaken the upper snowpack and form moist snow and crusts on sun-exposed slopes.

The upper snowpack is relatively complex. Strong northeast wind formed wind slabs in south to southwest terrain features last week. A few different layers of surface hoar and melt-freeze crust exist, which have recently acted as sliding layers. One such layer buried about a week ago may be found about 20 to 40 cm deep. The most widespread layer was buried late February and is now 60 to 80 cm deep. This layer is most commonly found in open trees (e.g. in this MIN) or sheltered terrain around the upper part of below treeline, treeline, and lower alpine elevations. This layer may only remain a concern in the north and east parts of the region.

The remainder of the snowpack is strong and well-settled.

Terrain and Travel

  • The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Be aware of the potential for large avalanches due to the presence of buried surface hoar.

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.

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.