Storm amounts for this region are anticipated to be light on Saturday. However, convective storm cells sometimes bring more snow than expected. Watch for thin wind slabs.
Confidence
Fair - Due to the number and quality of field observations
Weather Forecast
Saturday: Light snow above 1500 m, amounts in the 1-4 cm range, with rain/drizzle below. Ridgetop winds up to 60 km/h from the southwest. Sunday: A mix of sun and cloud. Freezing level around 1500 m. Ridgetop winds around 40 km/h from the west. Monday: Cloud increasing during the day, with flurries possible in the afternoon. Freezing level around 2000 m. Ridgetop winds around 50 km/h from the southwest.
Avalanche Summary
Loose wet avalanches to size 1.5 were reported from neighboring forecast regions (Lizard-Flathead and Waterton National Park) during warm periods through this week. This kind of activity is likely to be seen in this region when the sun comes out and/or temperatures become warm. Observations are becoming more limited as we enter into spring. If you're out in the mountains, please consider posting your observations to our webpage using the Mountain Information Network.
Snowpack Summary
10-20cm of recent snow overlies a widespread and supportive melt-freeze crust. In some areas, winds may have redistributed the surface snow resulting in wind slab formation in the alpine and exposed areas at treeline. Large cornices exist in the alpine and may become weak with daytime warming. The mid-March rain crust is down 35 to 70cm and has shown a good bond with snow above. Old persistent weak layers are still intact in the mid and lower snowpack and there may be potential for these layers to wake up with a big cornice fall, sustained warming and/or a significant rain event.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
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.