Avalanche Forecast

Issued: Apr 9th, 2015 9:22AM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Loose Wet and Cornices.

jfloyer, Avalanche Canada

South Rockies.

Warm temperatures may get locked in as clouds roll in later on. Watch for conditions that change with aspect, elevation and time of day.For details on how we issue Spring Danger Ratings, check out the Spring Changes Forecaster Blog here.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Friday

Weather Forecast

Friday: Cloud cover building through the day, flurries possible. Freezing level around 2300 m, southwesterly ridgetop winds increasing from light in the morning to around 40 km/h in the afternoon. 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.

Avalanche Summary

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.Loose wet avalanches to size 1.5 were reported from neighboring forecast regions (Lizard-Flathead and Waterton National Park) on Tuesday and Wednesday. This kind of activity is likely to be seen in this region through Friday, although the intensity may diminish just a little on account of less solar radiation and slightly cooler temperatures.

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

Loose Wet

Watch for pushy loose wet avalanche activity on sun exposed slopes. Loose wet avalanches can entrain mass quickly and travel long distances.

Be alert to conditions that change with aspect, elevation and time of day.>Be cautious of sluffing in steep terrain.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

Aspects: North, North East, East, South East, South, South West.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Cornices

Large cornices at ridgetop may fail under the weight of a person. Remember that destructive cornice falls become more likely during periods of warming and solar radiation.

Give cornices a wide berth when traveling on or below ridges. Remember that cornices become weak with daytime heating.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Apr 10th, 2015 2:00PM