Not such a good night for this particular snowmaking fan gun:
Fan guns make snow by spraying a fine mist into the path of air blown through the gun by fans at the rear of the unit. The mist freezes into snow crystals, which fall near the gun and form “whales”. The electric fans are powered by a nearby generator, while the water is fed at high pressure through a long line of hoses. If there is any problem with the electrical supply, the fans stop turning, but the water keeps coming. An extreme example of what happens then is illustrated in the above photo, taken near the top of Sunset Gully. Another day on the mountain…
A few days late for Christmas but welcome nonetheless, Lake Louise received some more snow over the last few days, improving conditions and allowing avalanche control teams to prepare more terrain for opening. At our Pika weather station, sensors recorded a total of 14cm, but depths up to 20cm were reported higher on the mountain and in wind loaded areas. At the same time, in a season where we’ve already seen a few instances of wind coming from the northeast, it happened again.
What does a northeast wind mean? Most of the time, Lake Louise gets southwesterly winds, resulting in fairly predictable loading patterns. In other words, southwest winds deposit wind-blown snow on the leeward northeast slopes. Lake Louise skiers know how much wind can improve areas like Boomerang and Whitehorn I & II, and avalanche control teams are good at predicting what avalanche conditions they’ll find after seeing recent wind and snow data. So, in short, southwest winds are why the front side of the Lake gets less snow than the back side – the wind picks up loose snow as it accelerates up the windward slopes, then dumps it on the leeward sides as it slows down and loses its ability to carry snow.
When winds come from the northeast, the loading patterns get reversed, and areas that usually benefit from loading get scoured, and vice versa. We saw these winds go into the 30km/h range, and while not strong enough to significantly change things, they did scour the tops, or start zones, of windward slopes. A good place to see how this affects a normally wind loaded slope is Rodney’s Ridge. For those travelling Saddleback, a quick peek over into Rodney’s Ridge/North Face will reveal scouring in the first few turns of the run, all along the ridge. The bulk of the slopes were not significantly affected, but stronger and more sustained winds could easily reach further down onto the slope itself.
Today, avalanche control teams are working in the Corridor/Crow Bowl/East Bowl areas, setting up fences and performing the last few rounds of control work before opening the terrain. Because the Corridor accesses the rest of the runs in that area, and is a long wind-exposed ridge, crews need to make sure that entry into the runs has not been too adversely affected by the northeast winds. With a little more snow, these areas will be ready to open.
In the overall snowpack picture, the colder than normal temperatures and shallower than normal snowpack has promoted the formation of hoar crystals, which are weak and offer little to no support for overlying snow. Once established these weak layers tend to stay around for the bulk of the season. Control teams are always working to flush these weak layers off of slopes, so that any future snowfall will have a chance to stay on the slope and form a stable foundation for the remainder of the season.
While the clear conditions we had expected did not materialize, the plan to perform avalanche control using a helicopter went ahead Wednesday morning at Lake Louise. Shortly after first light, an A-Star helicopter from Kananaskis Mountain Helicopters arrived at the resort and the control team prepared the more than thirty explosive shots that were going to be used in places like the front side of Eagle Ridge, Skoki Slides, the Lipalian chutes, and Richardson’s Ridge.
Most of the shots were “nukes” – two 1kg rounds taped together for extra bang. There was one single shot, and a few bags of ANFO, which is used to get an even bigger bang. One of the rear two-person seats in the helicopter was removed to make room for the shots, and four of us, plus the pilot, climbed in to the cramped cabin and got ready for the flight.
In the front left seat sat the patroller who would guide the pilot to the shot placements and let the one throwing the bombs when to be ready. In the back were the bomb thrower and a patroller next to him assembling the shots and lighting the fuses. Both doors on the left side of the helicopter were removed, and everyone tightened their seat belts and taped the clasps shut for an extra level of safety. It was quite cold in the cabin, but nobody really noticed as they were all focused on the job at hand.
All shots have fuses that burn for two-and-a-half minutes, so there’s usually time to place a few groups of two or three before moving away and watching the results. And, as expected, the results came, and despite poor visibility preventing us from reaching all targets, the mission was considered a success. What would have taken four or five days was accomplished in less than an hour, and control teams can now get back to working avalanche terrain from the ground and getting slopes ready for their eventual openings.
The following video was taken with two cameras – one HD helmet cam taped to the front of the helicopter skid, and the other held by me, sitting up front in the middle seat.
Wow. Around lunch time today, and after a morning of steady snowfall, Lake Louise was hit by a sudden and severe storm that lasted about an hour. Within minutes white-out conditions covered most of the mountain, thanks to heavy snowfall and winds gusting to 70km/h. Other than Glacier chair and Sunny T-Bar, all lifts stopped loading passengers and cleared their lines. Once clear, they were turned off to ride out the storm.
For about thirty minutes, the winds averaged 50-60 km/h. Heavy snowfall added another 5cm at the base area, and more higher up. With visibility reduced to near zero, skiers and riders stuck on the upper mountain tried to find their way down. At the same time, patrollers had to become creative in how they got back up the mountain without using lifts. There were calls for assistance from people who no longer wanted to fight the conditions. Skiers on the back side decided to either return to the front side via the Ski Out, or hunker down in Temple Lodge with a cup of something hot to wait it out.
As the winds quieted down and visibility slowly returned, the lifts reopened and people emerged to find clearing skies and some of the best powder skiing of the season. In some avalanche areas such as Whitehorn II, the sudden load of heavy wind-deposited snow caused numerous natural avalanches, all in closed terrain. Tomorrow morning (Wed), an avalanche control team will leave the ski area parking lot in a helicopter and perform about half an hour of aerial control work using explosives. With widespread avalanche hazard, a helicopter is by far the fastest way to cover ground, as it would take days for crews on the ground to match what a helicopter can do in half an hour.
There’s some great skiing out there, and with a little sunshine thrown in, Wednesday should be good at the Lake.
A snowy week and the first significant west/southwest winds of the winter at Lake Louise has given the avalanche control department even more to sink their teeth into these days. The cold weather of a few weeks ago had left its mark in the form of weak crystals in the snow close to the ground, and with the added load brough about by the new snowfall and wind, control teams were anxious to get into terrain most affected by these weather events.
With significant avalanches almost a certainty, control teams hiked up from the top of the Top of the World chair to the top of Paradise chair with packs full of explosive rounds. Their destination was ER 5, which is a huge piece of complex terrain with multiple avalanche paths and the potential to affect areas of the mountain that are already or soon to open. To access the usual shot placements, patrollers ski across the top of the Paradise Cornice and the top of the ER 5/6 shoulder, which leads down and eventually ends up at the top of Upper Kiddies’ Corner.
Starting at the very top of Upper ER5, two shots were placed, producing avalanches that ran almost down to the flats above Pika Corner, but not propagating. In other words, the avalanches picked up any snow that lay in their paths, but did not widen or cause additional areas to slide. Fracture line propagation usually happens when there are slab conditions, which form when wind-transported snow is deposited on leeward slopes. As a rule of thumb, the stronger the wind, the stiffer the slab. Slab avalanches are usually the most destructive due to the density of the snow and potential for increased propagation and large size. This was not the expected result, but with those areas cleared of snow the control teams moved down the ridge and to their next shot placements.
The next round of shots produced exactly the kind of results they expected – wide propagation and size 2-2.5 avalanches running just down to the flats. This became the story of the morning in ER5 as further explosive work produced slab avalanches that continued to remove most of the snow from the intended slopes.
Clearing snow off of slopes may sound counterproductive to some. In fact, this clearing out of widespread weak layers provided that area with the only chance it has in eventually becoming open to skiing this season. If the weak layers had been allowed to remain on the slope, the stability required for skier traffic would likely never be achieved. By starting fresh, the slope now has a chance to build properly with future snowfalls. Another benefit of the avalanches is that the debris gets deposited on the lower slopes. Avalanche debris consists of dense snow, and does a great job of filling rocky or uneven areas and providing a nice firm base for the run.
This morning, control teams are heading out along the Corridor and over to the tops of Swede’s and ER3. Their intention here is two-fold. First, they want to ensure the slope has a chance to become stable enough to open. Second, they want to make sure avalanches don’t start there and affect potentially open terrain below, as Paradise Bowl usually opens before Swede’s and ER 3.
If everything goes according to plan, control teams expect to have Paradise Bowl open today or tomorrow. There’s also a chance Lower ER5 could open as well, but more control work is required there, the results of which will determine if and when that run opens.
Meanwhile, it’s snowing in Lake Louise right now, and is expected to continue through the day. Things keep getting better!