Avalanche Forecast
Issued: Mar 29th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet, Wind Slabs and Cornices.
bchristie,
Avalanche Canada
A skiff of new snow may not be enough to float us over the firm surface underneath. Prepare for challenging travel conditions, and watch for loose wet and windslab avalanche hazard on isolated terrain.
Summary
Confidence
Weather Forecast
TUESDAY NIGHT: Cloudy. Light snow/rain expected, but up to 8cm at high elevations around Squamish. Light to moderate southwest ridgetop winds. Freezing level falls to around 1000 m.
WEDNESDAY: Cloudy. Light snow/rain expected, up to 5 cm at high elevations around Squamish. Light to moderate southwest ridgetop wind. Freezing level around 1250 m.
THURSDAY: Partly cloudy. Very light snow/rain expected. Light southwest ridgetop wind. Freezing level falling to around 750 m overnight, back up to 1400 m through the day.
FRIDAY: Mostly cloudy. Light to moderate snow/rain expected. Freezing level falling to around 750 m overnight, back up to 1400 m through the day.
Avalanche Summary
On Tuesday, small, loose wet avalanches were reported in steep rocky terrain. Explosive avalanche control produced a few small to large cornice avalanches.
On Monday in the Whistler area, explosive avalanche control produced cornice avalanches up to size 2.5, and a few small storm slab avalanches in the alpine. Small loose wet avalanche activity continued with warming and rider traffic.
Snowpack Summary
Around 5 cm of new snow falling with moderate southwest wind may form small, reactive windslabs on old, firm surfaces. With freezing levels falling to 1000m, a frozen crust is expected on all aspects into the alpine. On the highest peaks, above 2200 m, cold, winter snow may be found in shaded alpine terrain, with a sun crust on south facing slopes.
The rest of the upper snowpack consists of a number of crust/facet/surface hoar interfaces buried in March that seem to have bonded during the recent warm weather.
The mid and lower snowpack are generally strong and well bonded.
Terrain and Travel
- Be alert to conditions that change with aspect and elevation.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
- A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Loose Wet
Freezing levels are dropping, but mild daytime warming and spots of intense spring sun could make loose wet avalanches possible.
The size of these avalanches will be mostly influenced by how deep the loose snow is.
- If there is a solid, supportive crust on the surface, avalanches will be unlikely.
- If the temperature is above zero, the sun is on a slope, and there is very little wind to keep the surface cool, avalanches will become more likely.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Moderate southwest wind and the possibility of new snow may form small, reactive windslabs over firm surfaces.
- Watch for signs of instability like shooting cracks and recent avalanches.
- Windslabs can be most reactive when they are fresh, so tune in to loading patterns when you see blowing snow.
- Use small test slopes to see how windslabs are bonding to the old surface.
Aspects: North, North East, East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
With the fast change in temperature, and the possibility of new snow and wind, give cornices one more day of extra caution before returning to normal caution.
Good travel habits around cornices include:
- stay far back from the edge when you are travelling on a corniced ridgetop
- Avoid travelling under cornices, or put as much distance and terrain as you can between you and the cornice if travelling under them is unavoidable.
- Travel one at a time under a suspect slope, with eyes on the person crossing.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 30th, 2022 4:00PM
