Lizard-Flathead

Storm slabs may be reactive to human triggers, especially where they've been stiffened by the wind and sit on the widespread crust. Pay attention to how the new snow is bonding and heads up on the seemingly rugged travel conditions down low.

High pressure mostly dominates with the chance of some flurries overnight Friday then back to sunshine and cool temperatures for the weekend. Sunday evening should see the next change with possible snow forecast.

Alpine temperatures will be near -5 and freezing levels will be in the valley bottom. Ridhetop winds will generally be light from the south-southwest through the forecast period.

No new observations were reported at the time of publishing this forecast. 

On Wednesday, the new storm snow saw a poor bond to the underlying crust. Natural and human triggered avalanches were widespread and up to size 2 at treeline and above. Limited propagation was reported, however; these avalanches were running far and fast down the path as the snow slid on the crust. This storm slab may continue to be reactive to human triggers on Thursday and if the sun comes out loose dry sluffing from steep terrain features may be seen.

Have you been out? If so, we would love to hear about it on the Mountain Information Network. A picture is worth a thousand words! Thanks for your submissions. 

10-20 cm of new snow fell at upper elevations while the rest of the precipitation came in as rain or freezing rain. Reports suggest that the freezing rain occurred from 1900m to 2100m “ish” with rain at lower elevations which likely destroyed most surface hoar. All elevations are now hosting a burley crust under the new snow.

The recent storm slab may still be reactive to human triggers, especially where it sits above this recent rain/freezing rain crust or if it’s been sifted by the wind into deeper, stiffer pockets.

Digging deeper in the snowpack two predominant crusts exist from November. A widespread rain crust from early November that can be found up to 2500 m and buried down around 100 cm and a shallower one from late November down around 30 cm. These crusts have shown no recent reactivity in snowpack testing and this “potentially” problematic snowpack structure but remains on our radar moving forward.

The snowpack is thin and variable in wind-scoured areas, and it tapers rapidly at lower elevations. Snowpack depths at sheltered upper treeline elevations are 70-90 cm and still below threshold below treeline.

• Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
• Closely monitor how the new snow is bonding to the old surface.
• A crust on the surface will help bind the snow together, but may make for tough travel conditions.
• Be alert to conditions that change with elevation.