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Snow pack will get worse before it gets better

Warming trend will trigger more slides, but may help in long run

The word from the Canadian Avalanche Centre (CAC) is that avalanche conditions will actually get worse in the South Coast before they get better, but don’t write off the entire season just yet.

“What’s happening now is we’re in an extended warming period, and in the short term it’s going to cause more pain in the snowpack,” said Ilya Storm, an avalanche forecaster for the CAC in Revelstoke. “It’s going to increase the avalanche hazard.”

Storm explained that ice and hard snow form strong bonds, “but as you warm up the snow loses strength,” he said. “You can do things with snow or cold ice that you can’t do with a lake. As the snow warms, it causes the snow to creep, glide and deform more, and there’s more stress on these deep, weak layers we’ve been talking about.”

After a prolonged freezing period in December, the entire province was hit with storms of really dry, light, and powdery snow. Heavier snow followed, compressing that lower layer but not bonding with it. As a result, there is nothing to anchor all the recent snow to the slopes.

The upside is that the warming will trigger many natural avalanches, and could cause the weak layer to bond.

“We have a couple of ideas how it will play out, and in the long term the warming may — and I emphasize ‘may’ — help us,” said Storm. “It will help the snow to settle, and when it turns cold again it will strengthen. That could — and again I emphasize ‘could’ — help us in the long term.

“That’s the big question, and we won’t know the answer until we see how everything plays out, and whether it’s enough to help the deep weak layers.”

The other thing that could help stabilize slopes, “is 40 days and 40 nights of snow,” Storm adds. “A whole bunch of snow, followed by another cycle or two of big, amazing avalanches, should squish all this weak stuff together… until it’s one big coastal snowpack again.”

Storm says the current type of “upside down” snowpack is more common in the Rockies than the coast and interior of the province.

Rain could help, he said, by triggering natural avalanches quickly, but otherwise could create more problems by creating a crust layer that could be as dangerous as the dust layer, says Storm. Last winter, 2007-08, the instability that lasted most of the season was the result of rain earlier in the year.

“Rain on the mountain top is not like hitting the restart button,” he said. “It’s a double edged sword, on one side it could be good and possibly help the snowpack, on the other it could make things worse.”

Things have been busy at the CAC recently, with media attention and more demand for information. Storm recently fielded a call from a woman who was trying to convince her husband to avoid a trip into the backcountry.

“We’re being called in to settle domestic disputes,” joked Storm, although he is quite serious about the possible consequences of avalanches.

His advice to backcountry travelers is to stay at home, at least until after this weekend when they will have a better sense how warming may have impacted the snowpack. Even trips that stick to the tree line are not necessarily safe.

“(Tree line) is improving and will improve before the alpine, but not yet,” said Storm. “Right now your best friend is your terrain selection. Don’t try to assess the snow, try to select your terrain. That means avoiding the large features, and staying on small slopes, gentle slopes — places where if you’re wrong about the snow you can survive an avalanche.”

That’s the policy of most backcountry tour operators he’s in contact with, said Storm. “What I’m hearing from guides in operations and ski patrollers is that this is weird, and that they are being extraordinarily careful and disciplining themselves on the terrain they choose to travel on. A lot of the older guides are really pulling the reigns, because the younger guides haven’t seen this before.”

Closer to home, Whistler Blackcomb recently brought in snow scientist Chris Stethem to assess the situation. Stethem said that this type of snowpack hasn’t been seen on the coast since the late ’70s.

It may be impossible to open some of the high alpine until much later in the season. One attempt to open Pika’s Traverse, a green run from the top of Harmony to the Roundhouse, ended in near-disaster on Jan. 8 when a groomer was hit by a slide and carried 100 metres down the side of the run. The groomer operator sustained minor injuries from broken glass.

Avalanche control is also challenging. The weak layer is too deep to reach by ski cutting, which means that patrollers have to use bombs to set off avalanches.

Storm, who took his first avalanche course from Stethem, says that when a person of Stethem’s experience and knowledge says to stay out of the alpine, “you should probably listen.”

“Chris was working in Whistler in the ’70s when I took my very first avalanche course, he’s been around a long time, and his predictions usually nail it,” Storm said. “He’s also one of the few people who have a memory that goes back that far, and who has seen the conditions that we’re facing — not just in Whistler but across the province.”

As of Wednesday the CAC ranks the avalanche risk as High to Considerable in the alpine and treeline in the Sea to Sky and Duffey Lake and Inland areas. For updated bulletins, visit www.avalanche.ca.