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Waterton Lakes National Park staff monitoring avalanche dangers ahead of warm weekend

Jan 10, 2019 | 9:45 AM

WATERTON – Parks Canada urged backcountry users to stay out of avalanche terrain on Friday, Jan. 4, after a winter storm that led to an extreme danger rating in Banff, Yoho, Kootenay and Jasper national parks.

Not included in the warnings was Waterton Lakes National Park, and Visitor Safety Technician Adam Greenberg says the avalanche danger as of Wednesday, Jan. 9, in Waterton was rated at considerable in the alpine, moderate at the tree line and low below the tree line.

“What we were seeing last weekend is pretty much all along the Rockies there’s a weak layer of snow at the very bottom of the snowpack, and what you’re seeing in Yoho and Lake Louise was snowfall amounts of up to 70 centimetres that were overloading the snowpack on that weak layer. In Waterton, we were seeing snowfall amounts more in the region of 15 to 30 centimetres. Enough that we had some concern, so our danger rating did go into high, but not as extreme as other areas to the north.”

Traditionally in Waterton, the winter recreation area has been in the Cameron Lakes area, where people can access the alpine a lot easier.

“That area had been closed due to the Kenow Wildfire, but this year it’s open again,” Greenberg explained. “The road to access Cameron Lakes is open to non-motorized traffic, so people can walk, bike, or ski into the area and there’s also an Alpine Club hut there where people can stay to allow easier access to the alpine terrain.”

The Kenow fire in 2017 has affected the avalanche dangers in the alpine area to some extent, with Greenberg stating that Parks Canada contracted avalanche hazard assessment for the park in the aftermath.

“The initial assessments that came back that we’ve seen is we don’t really expect dramatic changes in avalanche activity in the park, but we might see changes in avalanche severity in some areas.”

So, just how has the fire impacted the snowpack in Waterton?

Park staff rely on three aspects of the forest to help create a stable snowpack.

“The forest canopy prevents snow from reaching the ground and limits how much snow can be moved by the wind and prevent the formation of some weak layers. In the burned areas, this canopy isn’t there anymore.

“We also rely on the structural support of tree stems to anchor the snowpack and reduce the chance of avalanches. In most places affected by the fire, those tree stems are still there and still doing their job.”

The last thing is small vegetation on the forest floor which provides support to the base of the snowpack, and in many places, this vegetation has been burnt and is gone, but in others, it’s been replaced with fallen timber.

“The combination of these changes has created the potential for some larger avalanches to occur, and in other cases, we might see small avalanches in places where they have not historically been an issue. As the years go by this is going to change as the forest grows back and the burnt trees begin to rot,” Greenberg said.

He says Parks Canada empowers people with the tools to make good decisions, so they issue avalanche forecasts twice a week as conditions change. 

“We always recommend that people check the avalanche bulletin, that they know the terrain rating of the area that they’re going into, that they have the proper training to interpret the avalanche bulletin and that they’re carrying essential safety equipment like an avalanche transceiver, a probe and a shovel,” said Greenberg, adding if people have the combination of those skills, equipment, and go to the right sources of information then the danger to them shouldn’t change at all.

They don’t do avalanche control in Waterton Lakes National Park, but Greenberg believes by taking into account the changes that have happened since the wildfire, they’ll be able to provide information that’s reflected in the avalanche bulletin that will help people to avoid areas where an avalanche may occur.

Despite the danger rating not being as high as other parks around the province, due to some of the slopes being barer than they were before after the Kenow Wildfire, there is potential that avalanches could sweep down other trees or vegetation further down the slopes.

“The report that we’ve got shows that we might see increases in the length of avalanches up to 200 metres in terms of how far they can run. Year over year for us the biggest factor in how big avalanches are going to be or how far they’re going to travel is the snowpack. Some years we have a really deep snowpack, several metres deep, that could be unstable with a weak layer at the bottom or it could be very stable. Other years we’ll have a very shallow snowpack that could be stable or unstable. The fire does have some effect, but the snowpack has the biggest effect on the avalanche hazard.”

Chinooks, like the one expected to sweep through Southern Alberta this weekend, also have an impact.

“Chinooks will warm the temperature, warm the snowpack and create additional load and stress generally,” Greenberg continued. “If you have warm temperatures over a long period of time, that can actually stabilize the snowpack.”

Greenberg says they’ve had a fairly mild winter in Waterton so far this year, and that has largely served to create a fairly stable snowpack except for those weak layers at the very bottom.

“That’s part of the reason why we weren’t seeing the same elevated hazard rating as areas to the north of us last weekend. If we have a short warming event, like we’re going to potentially see this coming weekend, what you’ll probably see is a spike in the avalanche hazard as the temperatures increase and the load and stress on the snowpack increase and then the hazard decrease as it cools, and the snowpack starts to tighten.”

Public avalanche bulletins are posted twice a week, with one that comes out on Monday evening and Thursday evening, which are valid for three days.

Even with some warnings, and factoring in how it’s a little harder to compare to normal because the access has changed Greenberg has been quite surprised at the number of people who are taking advantage of the access to the Cameron Lakes area.

“There’re people up there every weekend, and I’ve also been really impressed with the level of the people who are going in there. Everybody seems to be carrying the appropriate avalanche gear and everybody I’ve spoken to seems to be quite knowledgeable about the avalanche conditions and checking the bulletins.

“It’s great to see, and it’s also nice to see people taking advantage of these kinds of unique experiences that Waterton has to offer after the fire,” Greenberg said.