Avalanche Forecast

Archived

Apr 23rd, 2022–Apr 24th, 2022

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Purcells.

With a sunny spring day, check for good overnight re-freeze and make sure to be off slopes before they turn mushy or wet.

Confidence

High - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

Weather Forecast

SATURDAY NIGHT: Mostly clear, 10 km/h northwest wind, alpine low temperature -8 C, freezing level falling to valley bottom.

SUNDAY: Sunny with afternoon cloudy patches, 15-25 km/h southwest wind, alpine high temperature +6 C, freezing level rising to 2500 m.

MONDAY: Mix of sun and cloud with isolated flurries, accumulation to 5 cm, 20-30 km/h southwest wind, alpine high temperature +4 C, poor overnight re-freeze with freezing level hovering around 2200 m.

TUESDAY: Wet flurries, 5-10 cm. Light west wind, alpine high temperature +1 C, daytime freezing level rising above 2200 m.

Avalanche Summary

A few small (size 1) skier-triggered slabs occurred Thursday, about 30 cm deep and sliding on a crust. Additionally, a handful of wet loose avalanches to size 2 were observed on west aspects to 2350 m.

Wednesday saw small storm slab avalanches triggered in the west of the region at alpine terrain on north to east aspects, where they received up to 40 cm of recent snow. Otherwise, wet loose avalanches were triggered during the heat of the day.

Please consider posting your observations to the Mountain Information Network to supplement our data stream and help fellow recreationists.

Snowpack Summary

Sun and warm temperatures have moistened the snow up to 2400 m and on all sun-exposed slopes. Cold, dry snow persists on more north-facing and shaded aspects in the alpine and high treeline; in these areas use caution entering steep, lee terrain features below ridges, where wind slabs could be found. At ridge top, remember that cornices are large and looming.

Around 100 to 200 cm deep, faceted grains persist around a hard melt-freeze crust from early December. There's uncertainty on if and when this layer will wake up, but it could during the next intense or prolonged warm-up.

Terrain and Travel

Make observations and assess conditions continually as you travel.
Back off slopes as the surface becomes moist or wet with rising temperatures.
Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.