Avalanche Forecast
Issued: Mar 16th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Loose Wet.
mconlan,
Avalanche Canada
Avalanche activity may increase with mild weather and sunny periods.
Summary
Confidence
Avalanche Summary
Riders triggered numerous small (size 1 to 1.5) storm and wind slabs over the past few days within the recent storm snow, with some of them releasing on the surface hoar described in the Snowpack Summary. Most of them were at treeline to alpine elevations and they were 20 to 40 cm deep. Similar explosively controlled avalanches were reported.
Looking forward, the primary concern is the new snow that overlies surface hoar and/or hard interfaces. As the snow further settles and forms slabs, they will likely become touchy to human traffic. There's uncertainty on when exactly this will happen so travelling conservatively and making observations as you travel will be key. A warming trend with sunny skies could rapidly form slab properties within the storm snow.
Snowpack Summary
Steady light snowfall since Sunday has turned into about 30 to 40 cm of settled snow. This snow overlies large (10 to 20 mm), weak surface hoar crystals in shaded wind-sheltered terrain, wind affected snow in wind-exposed terrain, and a hard melt-freeze crust on sun-exposed slopes. Southwest wind is blowing the snow into deeper deposits in lee terrain features. Relatively mild weather and sunny skies may moisten the snow surface on sun-exposed slopes and at low elevations.
Another layer of surface hoar and/or weak faceted grains may be found about 60 cm deep, particularly on shaded aspects near treeline.
The remainder of the snowpack is consolidated and strong.
Weather Summary
Thursday Night
Partly cloudy with no precipitation, 20 km/h southeast wind, treeline temperature -4 °C.
Friday
Partly cloudy with no precipitation, 20 to 30 km/h south wind, treeline temperature -3 °C, freezing level 1000 m.
SaturdayClear skies with no precipitation, 20 to 30 km/h southeast wind, treeline temperature -1 °C, freezing level 1400 m.
SundayCloudy with snowfall, accumulation 5 to 10 cm, 30 km/h south wind, treeline temperature -3 °C, freezing level 1000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for changing conditions today, storm slabs may become increasingly reactive.
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Storm Slabs
Around 30 to 40 cm of snow is settling into storm slabs that rest on large and weak surface hoar in sheltered terrain and old hard interfaces elsewhere. As the snow consolidates and forms new slabs, the likelihood of triggering them will increase. Resulting slabs could propagate far.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
Mild weather and periods of sun will moisten the snow surface at low elevations and on southerly slopes. Best to avoid steep sun-exposed slopes during the heat of the day. Cornices may also weaken with daytime warming.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 17th, 2023 4:00PM
