Not a Cloud in the Sky
Posted: February 27, 2009 Filed under: Avalanche Control | Tags: Avalanche Control, Lake Louise, North Cornice Leave a commentIt’s been a fantastic week at Lake Louise, with a big storm dumping lots of fresh powder all over the mountain on Tuesday and Wednesday, followed by two days of bluebird on Thursday and today (nothing like a couple of sunny days on the slopes to recharge the ol’ batteries, eh?). The cats did a great job of laying down a whole lot of corduroy last night, and carvers had these groomed runs all to themselves for most of the morning.
Corduroy delight!
When the avalanche forecaster arrived at work this morning, the weather data from our Paradise top telemetry station reported about 12 hours of 30km winds or greater, starting right when the hill closed yesterday. Upon seeing this, his initial reaction was to expect significant wind-loading on lee slopes, since there was lots of fetch (snow available to be transported by wind) after the storm, and 30km winds, especially 12 hours of them, can move a lot of snow.
Since it was a clear morning, the forecaster grabbed his binoculars to see if he could see any signs of wind effect on the front side of Summit, which can be seen right from his desk. Contrary to what he expected, there were no signs at all of any scouring, which is the usual result when the wind comes from the southwest. That could mean a couple of things – either the cold temperatures immediately following the storm stiffened up the snow enough so that the wind couldn’t move it, or the winds were just low enough to hit our weather station, but none of the terrain. Once we got on the mountain, it was clear that it was the latter, since the new snow was still soft and would definitely have moved had the wind been low enough to do so.
On avalanche control, my partner and I headed to B and C Gullies of Whitehorn II, and when we unloaded the Summit lift we could see without even entering the run that the wind had only blown minimal amounts of snow, which had settled between the bumps that lie in the first 15 or 20 metres of the slope. Below that, there was no sign of wind-transported snow at all. The photo below shows the gate into Boomerang, and you can see the snow that was blown onto the cat track overnight, which isn’t much.
Boomerang Gate.
Once we were done in Whitehorn II, we went to join another team over at North Cornice, which had developed a bit of its namesake cornice from the wind that circles around from Bare Ass Pass and hits it from behind. As in other places, the loading was limited to the immediate lee part of the slope, so for the most part our mission was to knock the cornice down before it had a chance to grow too big and become a safety issue.
When controlling a cornice, the first team member will travel along the top of the ridge, kicking the cornice with their ski and trying to get it so that there is no overhang. The second patroller will travel behind the first and a metre or two below, ski cutting the slope that received the loading. Although it wasn’t in this case, kicking cornice can be a little frightening, since you hope that you’re not standing on the piece that decides to fall! If there’s any indication this might be the case, a patroller will travel along with the one doing the kicking, hanging on to them so they can pull them back if needed. The photos below show three patrollers as they move along North Cornice towards Lake Pitch, which is the eastern end of the feature and so named due to the little lake that lies in the flats below but hidden from view by ice and snow in the winter (click the link for Summer 07 to the right to see a photo of this area in the summer).
Moving along North Cornice.
Kick that cornice!
When we arrived at Lake Pitch, we could see pillow of wind-loaded snow that might be a concern, and while nothing we had seen so far this morning indicated it would be an issue, it was decided that to be sure we should use an explosive. When the snow is firm, like it was here, you need to tie the shot onto a length of cord and hang it over the cornice – otherwise you risk the shot bouncing on the surface and ending up at the bottom of the slope, where it is of little use. In the first photo below, you can barely see the shot hanging in place (though you may need to click on the photo for a lrger version to see better).
Shot in North Cornice Lake Pitch.
Kaboom!
A small result.
As you can see in the last photo above, only the top 5cm or so of snow reacted to the bomb, and we were satisfied that Boomerang, Brownshirt, and North Cornice were good to open. As we made our way back to Paradise chair, we watched two other control teams put some more ski cuts into Upper ER 5, which is slowly but surely getting closer to being open. Not yet, but we`re hoping soon!
Ski cutting Upper ER 5.
Avalanche Areas Below Tree Line
Posted: January 14, 2009 Filed under: Avalanche Control | Tags: Avalanche Control, comer's, Lake Louise 7 CommentsIn the wake of the storm that left over 60cm of new snow on the mountain, the avalanche forecaster was forced to consider parts of the mountain that normally aren’t a problem with regards to avalanche hazard. While many of the places are in the alpine, there are also a few that are tucked away in hard-to-find pockets hidden in the woods. While hard to find, they’re still in open terrain, so must be considered when planning the day’s avalanche control. Four of these areas are located on the front side of the mountain – Midstation Pocket to the skier’s right of Men’s Downhill, Ladies’ Pocket to the skier’s right of Ladies’ Downhill, Comer’s below Eagle Meadows cat track, and Paradise Pocket just above Pine Cone Way. These pitches aren’t big enough to attract those looking for untouched powder, but they are big and steep enough to avalanche and do get traffic nonetheless.
Comer's
On Saturday, two of us headed towards Comer’s and Paradise Pocket, since both can be controlled on the same lap. Dropping into Comer’s, there was lots of snow, and it was also apparent that there had been traffic throughout the storm, stabilizing the snow. Ski cuts here did not produce any results. Moving down to Paradise Pocket* the signs of traffic became less and less, and when we arrived at the top of the slope, we were pretty sure we’d get results.
Since the pocket looms directly over Pine Cone Way, we called a patroller to do a spot closure at the top of the run. A spot closure is just a temporary and usually brief closure of a run with a patroller standing guard rather than setting up closure fences and signage. Once the run was secured, we began by putting a ski cut across the top of the slope, which produced an immediate result as most of the feature avalanched the full length of the pitch. The skier’s left 1/3 of the slope did not slide, so I ski cut the top and got all of that to go as well. The debris ran to within a metre or two of Pine Cone Way, so not only were we glad to have closed the run, but also to have controlled the slope and removed any avalanche hazard.
The next photos are of Paradise Pocket before and after the avalanche, and you can see in the first how close the pitch is to Pine Cone Way. And, a short video (0:10) shows the first ski cut getting a good result.
Paradise Pocket - before.
Paradise Pocket - after.
It’s always good to go to places that are seldom visited in the course of a work day – there’s always something to be learned.
*It may seem strange that a pocket on the front side is named after a chair on the back side, but Paradise Pocket was named long before the chair of the same name existed. Perhaps it was named after Paradise Valley by Mt. Temple?
Heli-bombing
Posted: December 22, 2008 Filed under: Avalanche Control | Tags: Avalanche Control, Heli bomb, Lake Louise Leave a commentIn January of 2005, western Canada was hit by a huge storm that dumped precipitation everywhere from the west coast and over the Rockies into Alberta. This was a pineapple express – a term for a warm and wet system that originates around Hawaii. If you remember, virtually the entire ski industry in western Canada was shut down or severely limited because this storm produced rain, and lots of it. The only resorts to benefit from this storm, in the form of snow, were the four in Banff and Jasper National Parks due to their higher elevations. Lake Louise received close to 60cm in this one storm, and for three or so glorious days, skiers were treated to conditions that were about as epic as it gets. Then the temperatures warmed, and what had been a deep layer of soft snow was quickly turned to mush. It could have been worse – there were reports that large parts of Whistler/Blackcomb had been reduced to grass, and many other resorts had to close until it snowed again.
At Lake Louise, there was a sea of smiles as skiers enjoyed their good fortune. The avalanche control team suddenly had a very full plate of work to do, as not only did the sudden and significant snowfall produce an extreme avalanche hazard, but we had to go to places that normally weren’t a concern. One of these places was the Skoki Slides area of Mt. Redoubt, which lies to the immediate north of the ski area. The Skoki Slides are so named because in periods of high snowfall they have the potential to run across the normal ski access route to Skoki Lodge, another 9 or 10 km’s away. Skoki Lodge is operated by Lake Louise, and with a large number of guests scheduled to be making their way to the backcountry lodge that morning, it was crucial that avalanche control was performed to protect the route. Given the difficulty in accessing the terrain and the short period in which we had to do it, it was decided to call in a helicopter so that this work could be done safely and quickly.
A permit from Parks Canada is required every time a helicopter is used, no matter the reason, but because a helicopter is a tool that gets used every season for various purposes, a standing permit is applied for and issued at the start of each season. Then, when we actually book the machine, we just need to call the Parks service with dates, times, flight paths, and reasons for use, and the go-ahead comes quickly, especially in cases of public safety as it was here.
While we waited for the helicopter to arrive from Canmore, we assembled the explosives and produced a plan of attack. Upon arrival, we had a quick chat with the pilot, and off we went. The avalanche forecaster sat up front with the pilot in order to guide him to the areas we needed to go. The patroller who would throw the explosives sat next to the rear door, which was wide open. Another one sat next to him, and his job was to ignite and pass the bombs to the thrower. My job, of course, was to document the whole thing (although I didn’t realise until after that the camera I was using at the time was set to black & white).
The short (0:52) video below shows some of the action, and if you look closely, you’ll see that each bomb is actually two taped together. We wanted to make sure that if a slope was going to avalanche, we would help it do just that as much as possible. Two bombs packs twice the punch of one, and our access to this terrain with the helicopter was limited, so we wanted to ensure that either we got the slopes to avalanche, or that we were satisfied with the stability of the snow.
The fuses on each shot are 2.5 minutes, and since we moved along the slope and placed the explosives so quickly, we usually had time to turn around and hover in our front row seats to await the explosions and see what results we got, if any. The whole operation took less than 20 minutes, and when you consider that it would have exposed the workers to danger and taken the whole day to do the same thing without the helicopter, the advantages are clear.
Bomb thrower surveys his results.
Lake Louise Lowdown 