Issued: Sat, Feb 18, 2017 at 10AM

Expires: Sun, Feb 19, 2017

Above 2,500ft Moderate

1,500 to 2,500ft Moderate

Below 1,500ft Low

Degrees of Avalanche Danger ?

1. Low
2. Moderate
3. Considerable
4. High
5. Extreme

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

Observations from the last few days have found the recent storm snow to be settled and well bonded in most places. There is still some weakness near the bottom of the recent snow, around 60-90cm deep. Also, there are still density interfaces and wind slabs within the storm snow that may act as a weak layer and cause an avalanche in steep areas. Generally higher, colder, wind-loaded slopes will be the most prone to human-triggered slides.

There is a fair bit of variability out there above treeline as well. Some areas are well-bonded with thick slabs and little in the way of weak layers. Other areas have a noticeable hollow sound/feel beneath surface wind slabs. Avoid these areas.

Recent Avalanche Activity

The last observed avalanche activity was during the last storm cycle Feb 11-15th. There was a natural avalanche cycle within the new storm snow, with widespread D2-D3 slides on all aspects. These were dry slabs above 4000ft, and some nasty wet slabs below that level. A few large avalanches occurred, with crowns up to 2m tall. Some slides hit the valley floors and lower runouts.

Recent Weather

It’s going to be a beautiful week. With mostly clear skies, light-moderate winds, and mountain temperatures 10-25F with lots of sun. The next chance of significant snow will come mid-late week.

Temperatures have been below freezing, and winds light since our last storm on the 15th.

Feb 11-15th brought a pretty exceptional storm cycle. It started with 10-15″ of cold, weak, low-density snow, with another 10-15″ of heavy, wet snow above. This led to poor bonding within the new snow. We then had a significant rain-on-snow event on the 13th, with up to 2″ of rain falling below 4000ft. Rain reached up to 5000ft for a brief period. The cycle finished up with a nice shot of cold air and nice, fluffy snow 12-18″ on top of the saturated wet slop below. Temperatures dropped to 10-20F on the 16th as the storm cleared out.

Additional Info & Media

This is an important time to practice good group management skills and risk-reduction. This means keeping your group spread out while traveling in avalanche terrain. Ride one-at-a-time in any areas of risk, and only group up in safe zones well out of harms way. Evaluate each slope carefully, have an escape route, and a plan for what to do if an avalanche occurs. Always make sure every rider has a beacon, shovel, and probe, and knows how to use them.

Posted in Transitional Zone Forecasts.
Erik Stevens

Forecaster: Erik Stevens