BACKCOUNTRY AVALANCHE ADVISORY 

As of Wednesday, Feb. 21

Another week of relatively benign weather has gone by. Lots of sunshine, but still no sign of the elusive "big dump". Feb. 18 th brought us 10 cm. of new snow, but it wasn’t quite enough to cover up the variety of snow conditions created by the strong north winds that blew a few days earlier. The new snow produced some reactive soft slabs, but they didn’t have the depth to be a concern.

We haven’t seen any recent activity in the November facet layer, but we also haven’t had any good loading to seriously test the weakness. It is very difficult to predict how much of a trigger will be required to cause a failure in the deeper layers of the snow pack. Keep in mind though that the terrain with little snow cover should be considered the most suspect, particularly after a new snowfall or during the warm part of the day.

The sun is starting to pack more of a punch now – look around the mountains at the end of the day and you may see the telltale sluffs on the south and west aspects. Remember too that sunshine filtered through high cloud will create a "greenhouse affect" that often may cause a rapid decrease in the snow stability.

The clear cool nights earlier in the week produced a significant blanket of surface hoar that remained relatively undisturbed at all elevations. In places, the crystals were up to 15 mm. in length – the layer could prove to be a weakness when it gets buried by future storms. A good exercise for the neophyte snow scientist would be to watch this layer over the next month to see how it settles out and how long it takes to become unrecognizable.

Travel with caution in the backcountry. Your decision making should allow for the unpredictable event to occur – choose your route accordingly. As of Feb. 21, the avalanche danger is rated as MODERATE. Conditions may change rapidly, so talk to someone in the know or call the local phone bulletins for the most current information.

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