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Hectic weekend in Sea to Sky backcountry ends tragically with one dead, more injured

‘Very twitchy out there’: weak facet-crust layer contributes to onslaught of calls for Whistler Search and Rescue
WSAR Longline 2
Whistler Search and Rescue equips a helicopter for longline rescue after being called to the site of a fatal, Size 3 avalanche northeast of Pemberton on Saturday, Feb. 5.

One person is dead and several more are injured after a series of avalanches in the Sea to Sky corridor during the first week of February.  

The eventful week for Whistler Search and Rescue (WSAR) began on Tuesday morning, Feb. 1, when five local skiers were evacuated after three members of their group were injured in a Size 2.5 avalanche on Rainbow Mountain. The incident served as a grim preview of what proved to be a busy weekend for WSAR. 

At about 1:20 p.m. on Saturday, Feb. 5, Pemberton RCMP received “multiple emergency rescue calls in a 10-minute period” near Cassiope Peak, in the Duffey Lake area approximately 17 kilometres northeast of Pemberton. 

Four people were reportedly caught in an avalanche. Of those, two were uninjured and one, who suffered serious injuries, was evacuated via longline. The fourth, who witnesses identified as a woman, did not survive. 

What initially appeared as reports of two separate slides turned out to be one massive, Size 3 avalanche with a fracture line spanning about 1.2 kilometres. It ran between 500 and 800 metres down the slope and impacted about 10 ski-tourers and splitboarders in two unrelated parties, said WSAR manager Brad Sills. The avalanche was triggered in an upper treeline feature on a northeast aspect, according to Avalanche Canada.

Pemberton Search and Rescue (PSAR) responded with the assistance of WSAR, said PSAR manager David MacKenzie in a release, while Whistler Blackcomb Ski Patrol provided additional support. 

“We deployed search teams, including two helicopters, avalanche dogs, and a long-line rescue team” MacKenzie said in the release. “It is always difficult for our team when it is not always a positive outcome and our thoughts are with all the friends, families, and those involved today.”

Sills said the colossal slide occurred on the same weak, late-January crust-layer that led to the Rainbow Mountain incident. 

“Initial observations indicate this was a step-down avalanche, starting in a shallower layer then breaking into a deeper one,” read a Mountain Information Network (MIN) report on the Cassiope slide posted to Avalanche Canada’s website. “Two persistent weak layers are known to exist in the area, an upper surface hoar layer and a deeper facet/crust layer. Step-downs and wide propagations are characteristics often seen when persistent weak layers are the cause of failure.”

These kinds of sympathetic releases—when a nearby slide essentially triggers another avalanche—are “quite different than what we see here, typically, on the coast,” said Sills. “I think that’s why people are finding themselves in these situations. We just don’t have the depth of experience with the weather patterns that we’ve been getting, and people are just settled in their old ways [of thinking], ‘well, [the danger rating is] considerable, so it’s OK.’”

While on-scene in Pemberton, WSAR crews were also called to respond to reports of an injured snowmobiler initially thought to be in the Slim Creek/Leckie Peak area of the South Chilcotin range northwest of Lillooet. A team comprised of both Whistler and Pemberton SAR members flew to the reported site and spent “considerable time” searching, said Sills, but were unable to find any sign of the injured snowmobiler.

After being informed of the “non-existent subjects at Slim Creek,” RCMP investigated and discovered new coordinates placing the snowmobiler at the base of Mount Cayley, in the Powder Mountain Range west of Whistler. With night approaching, WSAR volunteers visited the Brandywine snowmobile parking lot to interview witnesses, who confirmed the event and location. 

Considering the two significant avalanche responses crews experienced in recent days, WSAR ruled out travelling over land through complex avalanche terrain at night. Instead—with the subject now exposed to cold weather for more than six hours—Whistler volunteers called on their North Shore Rescue counterparts to respond with their night-vision-equipped Talon helicopter. Rescuers were able to locate the subject, treat their leg injury and transport the snowmobiler to Lions Gate Hospital for treatment of hypothermia.

Saturday's incident at Mount Cayley was erroneously reported by Sea to Sky RCMP as another avalanche. According to Sills, the snowmobiler’s injury was caused by a manoeuvre gone wrong rather than a slide. “He hit a wind lip, landed hard and broke his ankle,” Sills explained.

Sills said officials are working to determine what caused the confusion surrounding the subject’s location, but presumed the inaccuracy was due to either a failure of the GPS unit in reporting the subject’s position or a miscommunication in the transcription of the coordinates.

“It is interesting that the locations are longitudally one above each other, so there is a possibility that it was a transcription error,” he said. “But we are investigating it and trying to figure out why, because it led to a delay that could have been avoided. And a lot of effort, too—we had two machines searching for two hours.”

Also on Saturday afternoon, WSAR’s helicopter was again configured for a longline rescue when crews were tasked with responding to a ski tourer who sustained a head injury while descending from the Hanging Lake area. Whistler Olympic Park (WOP) staff reported the incident. With help from WOP ski patrol, search-and-rescue crews extracted the injured skier from densely forested terrain and transported the subject to an awaiting ambulance. 

BC Emergency Health Services (BCEHS) confirmed in an email that four paramedic ground units and two air ambulance helicopters responded to Saturday’s incidents. BCEHS said two people were taken by air in critical condition, while two more people were transported by ground in serious condition and one was taken by ground in unknown condition.

‘It absolutely shocks me' 

WSAR crews were called to yet another slide in the Whistler area on Sunday afternoon, Feb. 7. The incident had all the ingredients for a disaster, said Sills, but fortunately had a positive outcome. 

Volunteers were tasked with responding to a group of six snowshoers who had set out with the objective of Spectrum Peak, past Hanging Lake and behind Rainbow Mountain. Two members of the group turned around earlier in the journey, while four snowshoers made it to the summit. As another two members of the group began their descent from the peak, the remaining two snowshoers thought they spotted an avalanche—which turned out to be a glide crack, explained Sills—and called for help after finding themselves too uncomfortable to proceed with the descent.

Though WSAR operated under the understanding that none of the snowshoers were equipped with beacons, two members of the six-person group were reportedly carrying avalanche transceivers. 

WSAR launched a helicopter response, and upon arrival on-scene found only two members of the party awaiting rescue. Between the time the other two snowshoers began their walk down and WSAR's arrival, an approximately Size 2 avalanche was triggered in the area. It appeared to run on the same problematic crust formed in late-January. 

Crews found footprints leading into the slide, but “for a short while, we couldn’t find footprints leading out of it, so that necessitated three dog teams to be readied to go,” said Sills. “I just can’t believe, given the experiences of the past week, that anybody would go that far back into the backcountry without transceivers and without any knowledge ... It absolutely shocks me.” 

The pair had luckily managed to avoid the slide, and made contact confirming they were safe and further down the trail before rescuers began probing. 


Following the action-packed weekend, Sills praised the cooperative efforts of neighbouring search-and-rescue organizations. “It’s really good to see all the SAR teams in the Sea to Sky corridor coming together when they are needed and helping each other,” he said.

“It’s just a tremendous set of skills that we have incorporated in these teams.”

Avalanche danger ratings elevate alongside freezing levels 

In the wake of these incidents, Avalanche Canada forecasters anticipate a “significant increase in the likelihood of avalanches” on the persistent weak layer during a warming pattern expected to roll into the region from Wednesday, Feb. 9 onward. The layer is so far proving to be most reactive between 1,800- and 2,000-metre elevations. The Sea to Sky’s danger rating for Thursday, Feb. 10 is listed as “considerable” in the alpine and below treeline, and “high” for terrain located at the treeline.

“The snowpack isn’t a fan of rapid change. Freezing levels jumping 2,000 m in a couple of hours on Wednesday is about as rapid as it gets,” read Avalanche Canada’s public bulletin for the Sea to Sky zone on Feb. 8. “Hazard from wet, loose slides might be the obvious problem, but an increasing likelihood of triggering a persistent slab is the most worrying.” 

While the weak layer responsible for the string of recent slides deserves attention, the snowpack is always changing, explained local avalanche expert Wayne Flann. 

“It’s never the same,” he said. “It’s just one of those things [that] keeps evolving … It’s important that you totally keep up with what the snowpack is doing on a daily basis.”

The snowpack can go from being unstable to stable “in half a day,” Flann continued. “It’s just a matter of keeping on top of everything and reading the reports and making good, educated decisions on where you’re going to ski.” 

And if people aren’t sure, “be conservative. That’s the one thing that you can always do,” Flann said. 

Now is a good time to lower your objectives, agreed Sills. 

“It’s very, very twitchy out there,” he said. 

“If you don’t want to stay home and read a book right now, then take up cross-country skiing, because it’s fantastic right now.” 

An earlier version of this story stated that WSAR responded to a group of five, not six snowshoers near Spectrum Peak on Sunday afternoon. It also stated that none of the six snowshoers were carrying transceivers, when two members of the group were reportedly carrying avalanche gear. This story was updated following publication after Pique received new information regarding the incident.