Purcells

Persistent slabs are possible to trigger in areas where the snowpack transitions from thick to thin or by a falling cornice

Evaluate terrain and avoid travelling below cornices

Over the past 3 days explosives were used to drop cornices, some of these cornices triggered persistent slabs on the slopes below. The resulting avalanches  were up to size 3 with crowns as deep as 3 meters.

On Tuesday several remote and naturally triggered cornice failures were reported. Some of these pulled slabs on the slopes below.

By mid day on Thursday up to 10 cm of new snow could have accumulated with moderate southwest wind. This new snow will overlie a crust on all aspects and elevations, except for north facing terrain in the alpine, Where up to 30 cm overlies a crust from late March. Below these crusts, the upper snowpack is moist.

Several weak layers from early March, mid February and late January can be found in the mid and lower snowpack. These layers remain a concern where a thick crust isn’t present above.

The base of the snowpack is generally faceted.

Wednesday Night

Mostly cloudy with 0 to 3 cm of snow. 15 to 30 km/h west ridgetop wind. Treeline temperature -9 °C.

Thursday

Mix of sun and cloud with 0 to 3 cm of snow. 15 to 30 km/h northwest ridgetop wind. Treeline temperature -6 °C.

Friday

Sunny. 10 to 20 km/h northwest ridgetop wind . Treeline temperature -2 °C.

Saturday

Sunny. 20 to 40 km/h west ridgetop wind. Freezing level rising to 2300 m.

More details can be found in the Mountain Weather Forecast.

• Keep in mind that human triggering may persist as natural avalanches taper off.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.
• Avoid areas with a thin or variable snowpack.