Above 2,500ft Moderate
1,500 to 2,500ft Moderate
Below 1,500ft Moderate
Degrees of Avalanche Danger ?
North winds were very strong above treeline earlier this week, causing recent wind loading on lee aspects and terrain features/gullies. The good news is that our snowpack is re-frozen and hard, which limited the amount of snow available for wind transport. Variability is high in the alpine, and any slopes with slabby layers near the top of the snowpack need to be treated with caution. Slopes with recent wind loading and 30 degrees or steeper should be avoided. Please send in any observations.
We have observed a layer of large facetted crystals about 60cm deep in this zone. This weak layer is slowly strengthening, but still poses a threat for deeper slides. Triggering this layer will generally be difficult, but heavy triggers like skier cliff drops, cornice fall, large groups, or a small avalanche may be enough to cause a failure on this layer. Avoid areas of thin snowpack, or rocky areas which will harbor trigger points for these deeper facet layers. It is possible to remotely trigger a large slope from trigger points on ridgelines or rocky areas at the margin of a slope. Use extra caution.
Recent Avalanche Activity
There were isolated areas of wet and dry loose slides coming down from steep/cliffy terrain, mainly on sun-affected slopes. None of this activity was large, and occurred during warm temperatures earlier this week.
This week has been a slow transition from arctic outflow event to onshore flow and incoming storm cycles. Light snow will start Thursday morning, adding up to a few inches perhaps by evening. A strong front will move in Friday with increasingly heavy precipitation and south winds. Snow levels will start at sea level, and rise to 1000-2000ft by Saturday morning. Around 2″ of liquid equivalent is expected during this time, adding up to around 2 feet of upside-down snowfall.
Cold and very windy weather occurred from the 6th-10th. Temperatures were in the single digits, with north winds at 40-80mph in many alpine areas.
Our last two snowfalls consisted of 6-12″ on Dec. 27th, and again on the 29th. The first storm produced cold, dry snow that made a weak base for the wetter, heavier snow that fell on the 29th.
Additional Info & Media
With recent very strong winds, expect unusual patterns of wind loading. This means areas lower down a slope, like mid-path and well below starting zones may hold pockets of dangerous wind slab. Expect a lot of variability out there and be ready for surprises.
2017 New Year’s resolution – develop backcountry habits to LIVE TO RIDE ANOTHER DAY:
- everyone in my riding group has a functioning beacon, probe, and shovel (& floatpack)
- my group chooses to avoid slopes with rocky trigger points
- my group chooses to avoid slopes with terrain traps; cliffs, gullies, and creek ravines
- my group agrees that one rider on a steep slope at a time is what we do
- my group gathers out of harm’s way, beyond the run-out
- my group reviews our day – where could we have triggered a slide? how can we improve our plan?