Avalanche Forecast

Archived

Jan 7th, 2023–Jan 9th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis, Bow Valley, Highwood Pass, North 40, Spray - KLakes.

Warm temps are helping to settle our current snowpack but its going to take a long time before we have any confidence in it. Expect to be wallowing in facets at lower elevations up to treeline as the snowpack is weak. The deep persistent problems are hard to predict and can have big consequences if triggered.

Confidence

Moderate

Avalanche Summary

Avalanche Control on Friday surprisingly produced minimal results which gave forecasters an uneasy feeling that this is a complex tricky snowpack.

Snowpack Summary

Large surface hoar was found today up to 2200m. This may be a layer to watch in the future.

Otherwise not much is changing in the snowpack (and that's not a good thing!). The mid-December surface hoar layer down 30cm at Treeline is reacting as a persistent slab with compression tests in the moderate range. Below this, the remainder of the snowpack is heavily facetted. Any avalanche triggered in the upper snowpack will almost certainly step down to the ground.

Forecasters are approaching all terrain conservatively and do not have much confidence in the snow pack, as it's one of the worst we've seen in many, many years.

Weather Summary

One day i will get to write in here "Up to 20cm" but unfortunately, that wont be today, or tomorrow.... or for a while.

Ridge of surface high pressure dominates over the Continental Divide. Mix of sun and cloud. Southwest ridgetop around 50 to 60 km/hin the KC region. Gusts up to 70 km/h through valley gaps across the Rockies in the morning east of the high pressure ridge. Freezing levels at valley bottom. Alpine temperatures near -5°C to -10°C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Problems

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.