Avalanche Forecast
Issued: Apr 18th, 2019 3:52PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
cgarritty,
Avalanche Canada
Snowfall and winds have been steady, but field observations are scant. Use this forecast as your starting point and gather information about the depth and reactivity of new snow as you travel. ..then post your observations to the MIN!
Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Thursday night: Clear periods. Moderate west winds.
Friday: A mix of sun and cloud with a chance of isolated flurries. Light to moderate west winds. Alpine high temperatures around -5 with freezing levels to 1300 metres.
Saturday: Mainly sunny. Light west or southwest winds. Alpine high temperatures around -2 with freezing levels to 1500 metres.
Sunday: A mix of sun and cloud. Light southwest winds. Alpine high temperatures around 0 with freezing levels to 1800 metres.
Avalanche Summary
A report from Wednesday in the Howson Range describes several very large (size 3) natural loose wet and wet slab releases in steep alpine terrain on a northeast aspect. This area received around 40 mm of precipitation over the week and activity here speaks to heightened avalanche danger in areas where new snow accumulations are deepest.
If you're out we'd love it if you would submit what you're seeing to the Mountain Information Network.
Snowpack Summary
Around 10 cm of new snow accumulated on Wednesday, bringing new snow totals to a variable 15-30 cm, with the deepest amounts found in the southwest of the region. The new snow has buried a melt freeze crust recently formed at treeline and below as well as on slopes that saw sun exposure after Saturday's storm. It adds to a wind-redistributed 5-10 cm of dry snow (from the weekend) on high elevation north facing slopes.
As we enter into mid-April we're dealing with a classic warm snowpack. At and below treeline the snowpack is becoming isothermal. We're tracking the April 4th crust which is down 20 to 40 cm below the surface on high elevation north facing slopes. Surface hoar and facets have been observed on this crust and a few days ago it was producing sudden planar results in snowpack tests.
Problems
Wind Slabs
Recent strong winds are suspected to to have stripped snow from windward (south to west) slopes and built fresh slabs on lee (north to east) slopes. This problem is likely to increase with elevation and toward the southwest of the region.
- Look for signs of instability like whumphing, shooting cracks, and recent avalanches.
- Avoid recently wind loaded features near ridge crests, roll-overs and in steep terrain.
- A bed surface of crust may prevent new snow from bonding well on south through west aspects.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 19th, 2019 2:00PM
