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Backcountry Advisory


As of Wednesday, March 7

Once again the week has given us only minimal amounts of precipitation. A weak system on March 1 deposited 10-20 cm. of snow on the local mountains, and produced some slab activity that was running on the underlying facets and surface hoar and within the storm snow. The recent warming and melt freeze cycles have since caused this layer to settle out and to become less reactive. On March 6, a natural slab release was observed on Overlord Mountain, likely the result of a cornice fall.

In the past month, there has been little avalanche activity running down to the November layer of facets. However, it will likely continue to be a concern for the remainder of the season. Be wary. March has been known to bring in sizeable, winter-like storms. Treat each new snowfall as if it will be the one to trigger the deep slab releases – avoid travelling on suspect terrain and be particularly conscious of overhanging cornices looming above.

We have reached the time of year when snow quality may change rapidly throughout the day. On solar aspects, the low-density morning snow will become more of a hazard as the day progresses. The slab also warms, becoming more fluid and more likely to fail on underlying weaknesses. Sun filtered through high cloud can be even more destructive than direct sunshine. We have all been surprised by those seemingly dull days, when the snow turns to mush and the unaware return home with brightly burned faces.

Don’t get complacent about the snowpack. The avalanche toll continues to slowly climb, and although no fatalities have occurred in our area, a quick look around with the binoculars will attest to the fact that people are crossing the smart risk line. It’s only a matter of time!

As for the stats, here is an interesting piece of information that pretty much sums up the split flow that has dominated the Pacific Northwest. Since Jan. 1, Los Angeles has received three times as much rain as has Seattle (15 in. vs. 5 in.). Over the weekend, a consolidating westerly flow is expected to move south towards our area bringing light precipitation. A slightly stronger disturbance may reach the region on Tuesday.

As of March 7, the backcountry avalanche danger is rated as MODERATE. This may deteriorated with daytime warming. If you are heading into the backcountry, consult someone who is familiar with the local conditions. Within the Vancouver to Lillooet corridor there can be a huge difference from one valley to the next, and the assortment of public bulletins out there can only suggest potential weaknesses, not pinpoint exactly where they are all going to be. The ultimate decisions will come down to you and your party. Make wise ones!

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