Avalanche Forecast Lizard Range and Flathead

Date Issued: Valid Until:

Avalanche Canada jleblanc, Avalanche Canada

Avalanche Forecast

Fri Mar. 15th ยท 4:24PM

Alpine

Danger Ratings Moderate

Treeline

Danger Ratings Moderate

Below Treeline

Danger Ratings Moderate

Problems

Storm Slabs Storm Slabs
Persistent Slabs Persistent Slabs

Alpine

Danger Ratings Moderate

Treeline

Danger Ratings Moderate

Below Treeline

Danger Ratings Moderate

Alpine

Danger Ratings Considerable

Treeline

Danger Ratings Considerable

Below Treeline

Danger Ratings Moderate
We're expecting mostly cloudy conditions on Saturday, but slopes receiving direct sun could produce loose wet avalanches surprisingly quick.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

FRIDAY NIGHT: Mainly cloudy, alpine low temperature -5C, light southwest wind.SATURDAY: Cloudy with sunny periods, alpine high temperature of -2C, light west wind at most elevations, moderate at ridgetop, freezing level around 2000m. SUNDAY: Sunny with cloudy periods, alpine high temperature of 0C, light west wind. freezing level around 2200m, no overnight re-freeze expected.MONDAY: Mix of sun and cloud, alpine high temperature of +3C, light west wind at ridgetop, freezing level around 2500m, no overnight re-freeze expected.

Avalanche Summary

On Thursday, a group of riders remotely triggered a size 1.5 persistent slab after seeing many shooting cracks and whumpfs. See the MIN report for more details. Several loose wet avalanches (size 1-1.5) were also triggered by riders on steep south facing slopes at treeline. A bit of natural activity, mainly loose avalanches, were observed on steep slopes. With this upcoming warming, natural avalanches are increasingly likely as the sun impacts solar aspects.

Snowpack Summary

The snow surface is getting moist on south and west slopes at lower elevations. Up to 40 cm of storm snow in the last week overlies various surfaces such as old and firm wind slabs in the alpine and open areas at treeline on all aspects. A widespread sun/ temperature crust is also found hidden under this new snow on south facing slopes. Isolated pockets of surface hoar crystals were observed at the surface on north-facing slopes around 2000m right before the last storm rolled in. The mid-snowpack consists of sugary faceted grains (facets) of different hardness. Two older layers of surface hoar still exist down 55-80 and down 95-150 around 1600-1900m. The lower snowpack is generally well-settled.

Problems

Storm Slabs

Storm Slabs

Recent storm snow may still be reactive, especially in wind effected areas. South facing slopes are also likely to produce loose wet avalanches.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Be increasingly cautious on sun exposed slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Possible

Expected Size

1 - 2

Persistent Slabs

Persistent Slabs

A surface hoar layer formed in late January may be more reactive than expected, especially at lower elevations during periods of intense warming.

Choose low angle terrain without convexities or terrain traps.Warming could wake up buried weak layers.Be cautious in shallow snowpack areas where triggering a deeper layer is more likely.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible - Unlikely

Expected Size

1 - 2.5