Special Avalanche Warning
The Canadian Avalanche Centre has issued a
Special Avalanche Warning for the 2nd... 3rd...4th weekend in a row. UNPRECEDENTED!
The Warning has expanded to include more regions of British Columbia.
March 13, 2010. – THIS IS THE LATEST UPDATE issued by the Forecasters at the Canadian Avalanche Centre. CLICK HERE
Pictures of recent avalanches have been posted on the CAC website. CLICK HERE
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Find answers to these questions – CLICK HERE to read the SPAW
- What’s the problem?
- Where is the problem most pronounced?
- How to manage risk?
- Travel Recommendations?
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_____________________________________________________Please copy THIS LINK and send to all your sledding contacts. Conditions like this are the perfect recipe for an avalanche accident.
What are the ingredients of this Special Avalanche Warning?
Below are some of the reasons why this SPAW has been issued. - Close call avalanches have been reported.
Several weaknesses are present in the upper meter of the snowpack right now. Snowmobilers and skiers have been triggering a wide variety of alpine and treeline slopes.
Mainly on North Aspects in the Treeline and in the Alpine. - Continued small storms are adding load to these weak upper layers.
Expected snowfalls are NOT forecast to be large enough to lead to a cycle of natural avalanches. Too bad, as a big dump of snow could possibly let nature clean off many of these unstable slopes for us.
- Common safe areas are suspect, catching people by surprise.
EVEN LOW ANGLE slopes are releasing right now. REMOTE TRIGGERING has also been reported.
This means that slopes may be releasing at a distance from the trigger point. You don’t have to be ON THE BIG SLOPE…JUST CONNECTED TO THE SLOPE.
*See the pictures and stories submitted from Zac’s students below
This little slide looks harmless…imagine it on a larger slope…or on a slope with a trap where the snow can accumulate leading to a deep burial. - Good weather and new snow will tempt people out to the slopes.
Weekends bring more riders. With more traffic people push the terrain even harder in search of fresh tracks.
- There is a lack of natural avalanche activity.
Without the obvious clue of naturally triggered avalanches people often get a false impression that the snowpack is stable.
Photo credit to Becky Corfe, Grande Prairie, AB
Why is this different from a forecast of ‘High’ or ‘Extreme’ avalanche conditions?
Statistically, recreational fatalities are more likely to occur during a period rated as ‘Considerable’. Why? - The definition of ‘High or Extreme’ avalanche hazard means “Natural and human triggered avalanches are likely or certain”
Often in a period rated as High or Extreme we are in the middle of a storm and there are fewer people out. Also, ratings of High or Extreme do not tend to last long.
- The natural avalanche activity alerts people to the unstable snowpack
People notice the action and ease off to simpler terrain.
- The avalanche rating of ‘Considerable’ means “natural avalanches are possible, human triggered avalanches are probable”
Basically this means that the snowpack isn’t unstable enough for the balance to tip with nature’s influence alone…but add the additional load of a sledder and the snowpack may struggle to hold together.
A Special Avalanche Warning DOES NOT mean that you cannot go riding in the backcountry. It means:
- ALWAYS READ THE AVALANCHE BULLETINS IF AVAILABLE IN YOUR AREA. Avoid the likely weak areas as identified in the Bulletin.
CLICK HERE for Avalanche Bulletins for Canada
CLICK HERE for Avalanche Bulletins for the United States. - Take an avalanche course to learn how to read an Avalanche Bulletin and to identify Avalanche Terrain and hazardous terrain traps. Successful use of terrain allows you to minimize your exposure to avalanche risk no matter the conditions. Avalanche courses are available in many areas.
- Learn to use the AVALUATOR to help you to choose terrain more suited for the posted avalanche conditions.
- Consciously adjust your choices of terrain. In many communities there is non-avalanche terrain where riders can enjoy the blue skies and fresh snow conditions away from the reach of the big slopes.
Zac’s Tracs last avalanche course of the season – GOLDEN, BC – March 5-7, 2010
Other avalanche course providers recognized by the CAC
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Feedback received from Zac’s Contacts during the SPAW
Hey Lori, Feb 19, 1:00pm
You’re talking low angles. This pic is from Hunters (Range) last weekend.
Riding on top of a rolling ridge as you can see when a crack propagated from my uphill ski and ran down about 300 feet in front of me. At the crest there was almost no slope at all and it still cracked!!!
The ridge was less than 10 degree for about 100 feet downhill of me with a tree ridge line at the crest above a 60foot drop.
Sure got the heart going, anything facing west, northwest was slabbing heavy on both hi and low approaches
Going to Blue River in a few hours! Cheers, R Lorenson
Thanks for sharing your story and pictures R.L.! Interesting conditions alright. The weak layer has such little resistance (low cohesion to the layer sitting on top of it) that even low angle slopes are failing.
A bigger dump of snow would likely lead to a cycle of natural avalanches that might clean many of these slopes off, however our snowfall amounts have been a quite low in many places throughout the province recently. We’ll see what the next week brings! Lori Z.
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Email received. Feb 23, 8:00pm
Hi Lori; Thanks for passing on the CAC warning, we were enroute to Fernie for a ride and got it on a Blackberry. We already knew it was very unstable and were planning a safe ride but hearing it thru you as well made us extra cautious and we all got home today!!!!!!While riding at Forester on Monday we saw a steep well supported slope that had been climbed by 2 sleds earlier that appeared to be popping out in a few places in 8’X6’ squares about 1’ deep between the sled tracks. They did not run anywhere, just popped out in a pile and sat on the slope. They were close to the bottom of the hill. It was probably 30-35 degrees and a 300 yard climb. Nobody had seen this before and were wondering if you have. My thoughts were that there was a lot of pressure on the snowpack and had it not been supported there could or would have been an avalanche. I realize that it is hard for you to say for sure not seeing it for yourself but would appreciate an educated guess. Rob S.
Hi Rob, Where was your camera!!! Sounds like a cool sign of unstable snow. May not have created an avalanche simply because the slab was not cohesive (connected) enough for the fracture line to travel anywhere. Can’t really speculate too much without a photo though.
Thanks for the note. We are always interesting to keep in the loop with what people are seeing out there. Glad that y’all made it home safely! Lori Z.
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Randy Zacaruk, photos from Barkerville, BC February 16, 2010.Sleds climbed up on the viewers left of this picture and then Randy dropped down on the edge of this windslab.
Check out the cracking that was triggered by his sled.
The slab was a little resistant and didn’t fully release until a second sled continued down the unstable patch.
Pay attention to signs of instability like this and take care on slopes with similar conditions. Continue to apply the skills learned in your AST 1 and AST 2 to improve your skills in recognizing variable snow conditions.
===================================Hey Lori and Randy! Feb 22, 2010
First of all thanks for the continued CAC special warnings, I want to relate a story from Friday Feb.19 2010It started out as a trip with just myself and a close friend who never gets out to the mountains. Before I knew it everyone at our mill knew we were going. Our group size (which should be a controlled issue) went from two up to six in a matter of hours.
Thursday morning when I logged onto the CAC website and read the bulletin the rating was Moderate and it seemed like the same old broken record that I had be reading over the past couple weeks, it mentioned the week layer of hoar 20cm down.
Thursday night I was busy loading up and didn’t check the CAC until Friday morning just before I left the house. All the sudden it was updated to Considerable and it mentioned “The current weak layer of surface hoar is producing avalanches that may occur on lower angles and be wider/larger than you would expect.” Wind loading was also mentioned.
That got me thinking about my group and how I was the only one with avalanche training and how you mentioned that most avalanche fatalities actually occur when the danger is rated as Considerable. I talked to my co-worker a little about avalanche safety on the way out in the truck but not as much as I should of. He did not have a beacon so I made sure he had one of my spares.I told everyone in the parking lot that we weren’t out there to ride beyond anyone’s abilities and that if they didn’t feel comfortable to let me know and we would change our plans accordingly, however those were just words to make everyone feel better, I was determined to make it up on the glacier. On the way in the group did awesome looking out for each other and I didn’t notice any avalanche activity until we rode up a slope that had been hardened by the wind.
At the top we seen the avalanche shown in the pictures above, it looked like just a small slide until we made our way down through the bottom. At the top we were only 2km from Mount Sir Alexander. I really wanted to press on and get there, however one guy in our group seen the slide and wasn’t so sure. We all went to bottom but him, he was getting his breathe and taking his time. I had told the group just before we crested the hill to stick together because of crevasse hazards as we were only 100m from where Kory fell in with his sled last year.
Once we were at the bottom of the slide and in the sun people began to play around on some small slopes which made me a little uneasy. Then all of a sudden one guy goes climbing up to the right of the slide you can see in picture above and a second sled follows up straight behind him.I start telling my buddy, “what the hell are those guys doing?! That guy is going to cut the face of that hill and bring it down onto the second sled.” Just as the words left my mouth the hill came down.
The sled lower on the slope quickly made his way to the left of the slide and into the old avalanche debris. Then he got up onto his sled and got ready to jump clear. Meanwhile the guy who started the slide was still on his machine and in control, he was content to just ride it, then he thought ‘I better try to ride out of the bottom of this thing in case it takes me under and sets up.’ He did out run the avalanche. Both of them had eye balls like saucer plates once they made it out. I had just put my camera away because I wanted to get out of the area.
The picture below shows the M1000 once we dug it out and got it turned around.
The slope is south facing and the time was about 2 p.m. the slope is 30 degrees. CAC Forecaster Anna Brown pretty much nailed that one in her bulletin!
Once I was back with in cell range I phoned my wife Lori and told her what happened, then she said “Yeah well didn’t you read that email Lori Zac sent out with the Special Warning!” The answer was no. I had logged on to the internet Friday morning to the CAC site to see the bulletin but did not check my hotmail account to see your email. My bad… C.W.
Hey C.W. Thanks for sharing your story. You are certainly right how fast things can go sideways even when we are trying to keep things in order.
Sledding is so different from skiing, hiking or climbing. We cover so much terrain so fast that it is super important that all guys are playing with the same game plan. Alert riders with ‘avalanche eyes’ sure makes a team more cohesive and a whole lot easier to manage without feeling like a nag.
As you experienced, travel habits and terrain and snowpack observations that seem so obvious to a rider with training aren’t necessarily within the radar of an unaware companion. A lot of the key avy safety messages seem like common sense, the thing is… we aren’t born with common sense…it is learned. It is always man’s choice to learn the easy way (in advance with guidance from experienced people) or wait and learn the hard way (in the moment through trial and error). I think your buddies might be ready for the easy way now!!
Glad to hear that everyone was ok. Maybe this will shake a few new guys out of the trees for our next avy class up there! In the meantime get them to check out the Free Online Avy Training that is listed in the side bar on the right side of this webpage! See you next season, Lori Z.
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Hi Lori. Feb 25/10
Keith and I were riding Fernie area for 6 days and noticed quite a few avys. A few were caused by sidehilling snowmobilers. The layers are not that stable as we were tought. They were mostly slab avalanches varying from 8 to 18 inches in thickness on the fracture line. We found buried hoar about 12 to 16 inches deep in many areas.
Thanks again for educating us, as the group decision to not climb Heartbreak on Sunday helped, as there were 4 avys when we rode back on Tuesday. We turned beacons to search for the heck of it and found no signals.
See you next year for more fun stuff, Level 2.
Ed D. (Hopefully I’ll send pics soon)
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While riding in Eagle’s Pass, Feb 28 we saw a fair amount of natural and sled triggered activity. Mainly on slopes 35 degrees and steeper. We used main trails to travel around and enjoyed the fresh snow in low angle terrain.
Later in the day, the guys thought that they would poke up the trees. I laughed and let them know that I would hang back with my beacon ready. Sure enough…they triggered this small slab and buried a sled up to the handle bars. ....told ya so! Gotta hate it when the girl is right! ;)
Slab avalanche remotely triggered (from up on the ridge). Notice the 2 frost layers. Both are likely to trigger by a sledder. Avalanches are likely to propagate wider as the upper snow layers become more bonded and have to reach further to find a weak point to stop the cross slope propagation and create a flank (side fracture).
Compression test results from a low point on the same slope CTM15 SP. Very fast shear at 5 taps from the elbow. Popped out the same two layers.
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