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 20th, 2024–Mar 21st, 2024

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
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

Purcells, Dogtooth, East Purcell.

While conditions are gradually improving with cooling temperatures, very large persistent slab avalanches may remain triggerable in areas not capped by a thick surface crust.

Confidence

Moderate

Avalanche Summary

Several naturally triggered persistent slab avalanches up to size 3 (very large) and numerous wet loose avalanches up to size 2.5 were reported on all aspects and elevations on Monday.

On Tuesday, a machine-triggered size 1.5 persistent slab was reported on a north aspect in the alpine north of Golden and explosives produced persistent slab and loose wet avalanches size 1.5-2 near Invermere.

Snowpack Summary

A skiff of new snow now sits over predominantly crusty surfaces. Dry snow may be found on high north aspects in the alpine, and moist surfaces may persist at low elevations.

A widespread, hard crust down 40 - 110 cm with weak facets above continues to be the primary layer of concern for human triggering of very large persistent slab avalanches.

The bottom of the snowpack is generally weak and faceted, with the potential to produce very large avalanches. The most likely areas to trigger this deeply buried weak layer are steep, rocky areas in the alpine with a shallow or thin to thick snowpack.

Weather Summary

Wednesday night

Cloudy with isolated flurries, 3 to 5 cm of snow. 10 to 20 km/h west ridgetop wind. Treeline temperature 0 °C. Freezing level 1000 m.

Thursday

Mostly cloudy with isolated flurries, 3 to 8 cm of snow (above 1400m). 20 to 30 km/h northwest ridgetop wind. Treeline temperature -1 °C. Freezing level 1800 m, dropping to valley bottom overnight.

Friday

Mostly cloudy with isolated flurries, 2 to 5 cm of snow. 5 to 10 km/h southeast ridgetop wind. Treeline temperature -5 °C. Freezing level 1500 m, dropping to valley bottom overnight.

Saturday

Mostly cloudy with isolated flurries, 2 to 5 cm of snow. 5 to 10 km/h southeast ridgetop wind. Treeline temperature -5 °C. Freezing level 1500 m, dropping to valley bottom overnight.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Conditions may have improved, but be mindful that deep instabilities are still present.
  • Keep in mind that human triggering potential persists as natural avalanching tapers off.
  • Be aware of the potential for large, deep avalanches to run full path or even longer.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.

Problems

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.