Avalanche Forecast

Issued: Apr 18th, 2017 4:28PM

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

mbender, Avalanche Canada

Cariboos.

Convective flurries and moderate southwest winds may form fresh wind slabs on lee features at tree line and above.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

WEDNESDAY: Cloudy with sunny periods/ Moderate southwest wind / Alpine temperature -7 / Freezing level 1100mTHURSDAY: Flurries / moderate southwest wind / Alpine temperature -4 / Freezing level 1600 mFRIDAY: Mix of sun and cloud / Light west wind / Alpine temperature -3 / Freezing level 1700mNOTE: Convective flurries which are common during this time of year can result in widely varying snowfall amounts throughout a region. These spring squalls routinely drop 20+ cm of snow in one valley while the adjacent drainage remains dry. For this reason, the distribution of avalanche problems associated with new snow, such as wind slabs, can vary greatly within a region.

Avalanche Summary

Several loose wet avalanches to size 2 were reported on a variety of aspects in this region on Sunday. Exposure to large overhanging cornices remains a significant concern.

Snowpack Summary

Recent new snow tree line and above has been redistributed by west and south winds. Cornices remain large and continue to become more overhanging. The middle of the snowpack is generally well settled and continues to transition into a spring melt/freeze regime except for high elevation northerly aspects. Expect the entire thickness of the snowpack to be moist or wet at lower elevations. At upper elevations a deep persistent layer consisting of facets sitting on a crust that was buried back in November has been sporadically reactive to heavy loads i.e. a cornice fall or the weight of a smaller avalanche running.

Problems

Cornices

The likelihood of cornices triggering increases with intense sunshine and/or during the warmest parts of the day.

Cornices often break further back than expected; give them a wide berth when traveling on ridgetops.Minimize exposure to cornices and sun exposed slopes when the solar radiation is strong.Cornice falls have the potential to trigger deeper buried weak layers.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Wind Slabs

Convective flurries and moderate winds may have formed fresh wind slabs on lee features tree line and above.

Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 19th, 2017 2:00PM