Avalanche Forecast

Issued: Mar 15th, 2018 4:12PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Storm Slabs, Loose Wet and Deep Persistent Slabs.

mconlan, Avalanche Canada

South Rockies.

Recent precipitation fell as snow at higher elevations and a mix of snow and rain at lower elevations. Observe for signs of instability, such as cracking, whumpfing, and avalanche activity -- each elevation band will be different.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

FRIDAY: Early-morning sunshine and afternoon clouds, light easterly winds, alpine temperature -4 C, freezing level rising to 2000 m.SATURDAY: Cloudy with snowfall, accumulation 5 to 10 cm, light northeasterly winds, alpine temperature -7 C, freezing level 1500 m.SUNDAY: Cloudy with light snowfall, accumulation 5 to 10 cm, light easterly winds, alpine temperature -9 C, freezing level 1200 m.

Avalanche Summary

Loose wet avalanches were reactive to skier traffic below treeline on Thursday.

Snowpack Summary

Around 15 to 25 mm of water equivalent fell in the region on Thursday. This would have fallen as snow at higher elevations (likely up to 25 cm of snow) and partially as rain at low elevations. This precipitation fell on a thick melt-freeze crust that exists on all aspects from recent warm temperatures and rain, except for possibly higher elevations on north aspects. The upper snowpack may still be wet at low elevations.A weak layer of surface hoar buried mid-February exists in parts of the region around 50 to 80 cm deep. The lower snowpack is weak with a combination of crusts and facets near the bottom of the snowpack that are widespread.

Problems

Storm Slabs

Around 15 to 25 cm of snow likely fell at higher elevations in the region, particularly in the eastern slopes. Observe for signs of poor bonding of the new snow with underlying surfaces.

Keep an eye out for localized areas of deeper snow accumulation, particularly on eastern slopes.Observe for signs of instability, such as cracking, whumpfing, and avalanche activity.Use caution in lee areas in the alpine and treeline. Storm snow may form touchy slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

High freezing levels and recent rain have moistened the snowpack at lower elevations. Use caution in terrain features where a small avalanche could have serious consequences.

Watch for signs that the snow is moistening such as pin-wheeling and point-releases below cliffs.Avoid terrain traps such as gullies and cliffs where small avalanches can have high consequence.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Deeply buried weak layers linger in the snowpack. These layers are most likely to be triggered from thin snowpack areas.

Avoid steep, rocky, and shallow snowpack areas where triggering deeper layers is more likely.Pay attention to overhead hazards like cornices which could trigger deep persistent slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3.5

Valid until: Mar 16th, 2018 2:00PM