Avalanche Forecast
Issued: Mar 28th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Cornices.
cgarritty,
Avalanche Canada
Be in initial assessment mode as you check out the outcome of the storm, especially if forecast snowfall is exceeded. Expect to find reactive new wind slabs in exposed terrain but keep your guard up in sheltered areas until you have good info about how the new snow is bonding.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain.
Weather Forecast
Sunday night: Clearing. Strong northwest winds. Freezing levels returning to valley bottom.
Monday; Mainly sunny. Moderate to strong northwest winds. Alpine high temperatures around -9 with freezing levels to 1000 metres.
Tuesday: A mix of sun and cloud. Light variable winds shifting southwest. Alpine high temperatures around -3 with freezing levels climbing to 1600 metres.
Wednesday: Sunny. Light southwest winds. Alpine high temperatures around 0 as freezing levels climb to 2000 metres.
Avalanche Summary
A report from Mt. Rohr on Saturday showed a fresh cornice triggered slab from a steep piece of terrain, a great reminder of cornice and associated avalanche hazards.
Avalanche activity on Friday was limited to loose wet avalanches to size 1.5 from steep terrain facing the sun.
Looking forward, new snow from Sunday's storm may need a day to settle and form a good bond with the old surface. Extra caution should be taken in wind loaded areas, which may begin to include more south slopes as a forecast shift to north winds takes place.
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Snowpack Summary
Up to 30 cm of new snow may accumulate by the end of Sunday's storm in the south of the region with likely closer to half that in the north of the region.
The new snow has buried a mix of widespread hard crust and a bit of moist new snow below about 1700 metres and to either sheltered low density or wind affected dry snow above this elevation. The lower snowpack is strong and settled.
Remember that cornices along ridgelines are large at this time of year and always have the possibility of failing naturally or from the weight of a human.
Terrain and Travel
- Closely monitor how the new snow is bonding to the old surface.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
New snow through Sunday night and shifting winds on Saturday are likely to form a reactive new wind slab problem in exposed areas. Investigate the bond of the new snow in sheltered areas to ensure a more widespread storm slab problem isn't in play. This is more likely in the higher snowfall south of the region.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are large and looming along many ridgelines, and have likely grown with the recent snow and wind.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 29th, 2021 4:00PM
