Banff Yoho & Kootenay National Park Avalanche Forecast
Issued: Apr 15th, 2021 4:44PM
The crux of the big warmup approaches. We expect a good overnight freeze for Friday, but no freeze for Saturday morning. Be clear of all avalanche terrain by noon and do something else if the snow is not frozen. Saturday might be too warm and slushy.
The clear skies and warm, sunny weather will continue until Sunday, getting slightly warmer each day. Freezing levels are forecast to reach 3000 m on Friday and a poor freeze is expected on Friday overnight. Saturday could be "the day" for avalanches. The next few days is the biggest warmup to 3000 m so far this year.
Hard surface crusts in the morning, then wet snow in the afternoon. High elevation north aspects will still hold dry snow. Another solid overnight freeze is expected for Friday morning, then deteriorating rapidly as the day warms up. There are several persistent layers n the mid to lower snowpack will wake up over the next 48 hr.
Many loose snow avalanches up to size 2 were observed from the valley bottom on Thursday, running long distances in gullies. We had no observations after 2:00 pm, and expect the peak of avalanche activity to be later in the afternoon, so these observations are likely incomplete.
Expect widespread wet loose avalanches in all gullies on Friday and Saturday. Don't expose yourself to any gully features once the day begins to warm up.
- Daytime warming will weaken surface layers, plan your day around being back to the trailhead early.
Aspects:East, South East, South, South West, West.
Cornices are huge and are failing consistently, sometimes triggering deeper layers in the snowpack. With the intense solar input forecasted, they may start to fail early in the day.
- Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.
- Give cornices a wide berth when traveling on ridges.
Aspects:North, North East, East, South East, North West.
Be wary of large slab avalanches on Friday and Saturday as the heat penetrates deep into the snowpack and wakes up some old persistent weak layers. Do not expose yourself to any avalanche terrain after noon.
- Pockets of persistent slabs linger on alpine lee features.
- Pay attention to overhead hazards like cornices which could trigger persistent slabs.
Valid until: Apr 16th, 2021 4:00PM
The latest forecast danger ratings, broken down to elevation. See how an elevation is trending.