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

Apr 5th, 2015–Apr 6th, 2015

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

South Rockies.

Snowpack and avalanche observations are becoming scarce. If you've been in the backcountry, please tell us what you've seen here on the Mountain Information Network.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

A system to the south of the border will bring precipitation to the region Sunday overnight and Monday. Models are currently showing 5-10mm of precipitation and eastern upslope areas can expect to see the most accumulation. Alpine winds are forecast to be moderate-strong from the SE to E and freezing levels are expected to reach around 1500m on Monday afternoon. On Tuesday, a ridge of high pressure moves over the interior and becomes the dominant feature for the rest of the week. A mix of sun and cloud is expected for Tuesday with light alpine winds and freezing levels reaching around 2000m. On Wednesday, mainly sunny conditions are expected with light alpine winds and freezing levels reaching around 2200m.

Avalanche Summary

Observations are becoming very limited as we enter spring. If you're out in the mountains, please consider posting your observations to our webpage. On Thursday, some loose sluffing was reported from steep terrain. On Saturday in the Lizard region, widespread sluffing was reported from steep terrain features and ski cutting produced soft slabs in wind loaded features. On Monday, it may be possible to trigger new wind slabs in the alpine and exposed areas at treeline. Reverse loading may occur and wind slabs should be expected on all aspects. Cornices may become touchy during the afternoon.

Snowpack Summary

10-15cm of recent snow overlies a widespread and supportive melt-freeze crust. Ongoing moderate-strong winds have redistributed the surface snow resulting in wind slab formation in the alpine and exposed areas at treeline. The winds on Monday are forecast to be from an easterly direction so reverse wind loading can be expected and wind slabs may exist on a variety of aspects. The mid-March rain crust is down 35 to 70cm and has shown a good bond with snow above. Old persistent weak layers are still intact in the mid and lower snowpack and there may be potential for these layers to wake up with a big cornice fall, sustained warming and/or a significant rain event. Large cornices exist in the alpine and may become weak with daytime warming.

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.

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.