Complex Snowpack and the Potential for Remotely-Triggered Avalanches
It has been quite the winter season in my neck of the woods. We started November off with some amazing snow which never seemed to stop falling. Then it did, for a very long time. And it got cold—flipping cold—for a very long time. Then it finally started snowing again. And then it stopped and got cold again. You get the picture. These drastic changes in weather—including long periods of drought, cold weather, and finally snowfall—have created a very complex snowpack. And with the recent and welcomed return of winter, this complex snowpack is beginning to show its very ugly teeth.
A Complex Snowpack
We now have a depth of snowpack upwards of 3m. In its depths are several—and very significant—Persistent Weak Layers (PWLs). These PWLs consist of a very weak grain form or interface between two stiffer layers of snow (slabs). And these weaknesses are not going to heal anytime soon—hence the term persistent.
A quick look into the snow will tell you what demons are lurking.
We have begun to see some very large avalanches. Yet many of us fear that this is just the start of something big.
I have been reading avalanche hazard bulletins for a very long time. But I honestly cannot remember a time when I last looked at an Avalanche Canada bulletin and saw Size 4 avalanches forecasted. Size 4! And right now the possibility of triggering such massive avalanches is forecasted to be “likely”. That’s insane!
I often talk about the avalanche hazard, snow stability and issues within the snowpack on social media. But right now, we are dealing with possibly the spiciest snow pack in years. If you have never listened to the warnings before, you best listen up this time.
This is not your average winter and I hope that this message is getting across.
The Potential for Remotely-Triggered Avalanches
Right now we are seeing very large avalanches releasing from very light triggers—even by people not on or even near a slope. We call it a “remote trigger”. This is a scary phenomenon. It means that you can trigger an avalanche from an area that you thought was safe, or from simply by riding below a slope.
This avalanche was remote triggered from over 20m away.
A look at the crown of the avalanche above. The avalanche was a 105cm slab on a PWL developed in January.
Here’s what can happen. Our movements or ground pressures can cause a failure in the snowpack even when we’re not near a slope. Quite often, avalanches can be remotely triggered from below, and the location of the trigger can be overrun by the avalanche. These situations can be quite difficult to predict, and we are best served to increase our margin of safety anytime we are uncertain.
Another remote avalanche on a Persistent Weak Layer (PWL).
Recently we have seen several large, remotely-triggered avalanches in our area and one had a horrible outcome. One is too many. I would like to do everything I can to ensure that it does not happen again. Beginning a serious discussion now is the best step forward.
It’s Going to Get Worse Before It Gets Better
Currently we are faced with weather warnings all across the interior of BC for this week. That means an even more significant load on an already untrustworthy and complex snowpack.
I see all my friends on social media getting stoked and heading into the backcountry to enjoy all of this new snow—and that’s awesome. I’m going to be doing the same thing. BUT, I am going to head out there with my 850 and just enjoy being outside in the mountains with good friends.
Testing small slopes before moving on to bigger terrain.
The trick to getting out and getting home at the end of the day will be: sticking to low-angle terrain (even lower than normal), and being mindful of your surroundings. This must include anyone around you. And be very sure not to expose yourself to any overhead hazards.
Just keep it simple and smash pow!
Restraint and willpower will be the keys to success over the foreseeable future. Ride safe friends.
– Curtis
Curtis Pawliuk is the owner/operator of Frozen Pirate Snow Services and the general manager of the Valemount and Area Recreation Development Association.