Avalanche Forecast

Issued: Apr 18th, 2018 5:04PM

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

jsmith, Avalanche Canada

Lizard-Flathead.

Sunshine and rising freezing levels will increase the likelihood of loose wet avalanches and cornice failures. Minimize exposure to sun exposed slopes when the solar radiation is strong.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

THURSDAY: Sunny. Light southwest wind. Alpine temperature +6. Freezing level 2400 m.FRIDAY: Sunny. Light to moderate southwest wind. Alpine temperature +6. Freezing level 2500 m.SATURDAY: Mix of sun and cloud. Strong southwest wind. Alpine temperature +1. Freezing level 1800 m.

Avalanche Summary

Several naturally triggered size 2 storm slab avalanches were reported on north to east aspects, between 1800-2100 m near Fernie on Tuesday. Avalanche reports have been limited due to very few information sources this time of year. If you have been out, please post your observations on the Mountain Information Network (MIN).

Snowpack Summary

Cornices are large and looming. Lingering storm slabs formed by 20-30 cm of recent snow may still be reactive to human triggers; especially in wind affected terrain. This storm snow overlies numerous crusts in the upper 100 cm of the snowpack. The mid-pack is generally well settled and strong.A layer of sugary facets around a crust can be found near the bottom of the snowpack which has been dormant for some time. Large triggers, such as a falling cornice, or a major warm-up to the snowpack could trigger this layer.

Problems

Loose Wet

When the sun comes out it will quickly weaken the new snow and cause loose wet avalanches on steep solar slopes.

Minimize exposure to sun exposed slopes when the solar radiation is strong.Watch for signs that the snow is heating up such as pin-wheeling or the surface snow becoming moist.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Storm Slabs

Lingering storm slabs may still be reactive to human triggers in wind affected terrain.

Watch for signs of instability such as whumphing, cracking, or recent natural avalanches.Use caution when transitioning into wind affected terrain.Extra caution needed around cornices with current conditions.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

Sunshine and warming temperatures will increase the likelihood of cornice fall.

Cornices become weak with daytime heating. Give them a wide berth both from above and below.Falling cornices may trigger persistent weak layers deeper in the snowpack.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Apr 19th, 2018 2:00PM