Surface Hoar Frost From High Pressure Is About to Get Loaded

Surface hoar frost formed during recent high-pressure weather is about to become a serious avalanche problem as a series of potent storms moves into Western Canada, with Avalanche Canada forecasters urging backcountry users to dial back exposure to avalanche terrain.

The combination of new snowfall, mild temperatures, and strong winds is poised to rapidly increase avalanche hazard across many regions.

Extended cold, dry, high-pressure weather through January allowed a surface hoar layer to form across the snow surface. Over the past two weeks in particular, large surface hoar crystals developed during clear nights.

That weak layer is now being buried and loaded by incoming storms.

As snowfall accumulates and winds build slabs on top, this surface hoar becomes increasingly reactive. Warming temperatures and additional precipitation will further stress the layer, significantly increasing the likelihood of human-triggered avalanches, especially in alpine and treeline terrain.

Surface hoar is a classic persistent weak layer. Once buried, it bonds poorly with new snow and can allow fractures to propagate across wide areas. Conditions may feel supportive underfoot, but stability can be misleading—and consequences can be high.

Before heading out, and again on the day of your trip, consult the latest regional avalanche forecast from Avalanche Canada.

In the field:

• Choose conservative terrain – Stick to lower-angle slopes without overhead hazard and avoid wind-loaded features.

• Respect storm and wind loading – Strong winds can rapidly build slabs even with modest snowfall amounts.

• Be prepared – Ensure everyone in your group carries avalanche rescue gear and knows how to use it efficiently.

Hoar frost formed during recent high pressure is now being loaded by new snow. The combination of storms, warming temperatures, and this buried weak layer demands caution.

Adjusting objectives and minimizing exposure to avalanche terrain right now isn’t just smart—it’s essential.

Be safe, powder people. Live to play another day.