Experts blame climate change for Stawamus Chief landslide that rocked Squamish village

The town of Squamish, British Columbia, was rocked by two rock slides within 24 hours on Monday, with a huge slab of granite shearing through a section of the Stawamus Chief and crashing to the ground early in the morning.

The chef is a massive granite dome to the south of the city, popular with tourists and climbers.

The first dramatic landslide, which occurred around 1:34 a.m. PT and was captured on webcam, left an iron-tinted scar on the rock face after a bloom of sparks and plumes of dust. A smaller slide hit around 4:45 p.m. PT near Angel’s Crest Trail as people lined up to vote in the federal election.

Alexis Birkill, who runs Chiefcam.com, recorded the rocks as they crashed into the upper zodiac wall.

No injuries have been reported, but BC Parks and Squamish RCMP are urging people to stay away from the area where the Western Dihedral meets the Great Wall.

Climbing walls are closed while geotechnical engineers work to ensure safety. The closures are expected to last all winter, with fears that rain and then freezing temperatures could trigger more debris falling from the old rock face.

A reddish-brown iron-tinted scar can be seen where a huge granite pillar sheared Chief Stawamus on September 20 and fell into the rubble at the base. (Tim Cyr)

Some experts say climate change could accelerate the number of landslides that are often triggered by heat waves followed by rain. The extreme temperatures this summer may have caused the rock to expand and then contract in cold weather, creating stress fractures. Once weakened, heavy rains helped loosen the rock.

Gio Roberti, an avid mountaineer and climate change risk expert at Minerva Intelligence Inc., said the largest rock slide started two days after Friday’s 100-millimeter precipitation.

“It took a while for the water to seep through all of these cracks and push the pillar of the wall,” said Roberti.

The rumbling rock cascade recorded on a local seismograph. The last such large slide on the north or zodiac wall was reported in 2015. Five rock falls were reported this year, and three more occurred on the large wall in late June and July.

Rumbles like thunder

Anne Bright was awoken by the rumble of what she thought was thunder or an earthquake shaking her home around 1:34 a.m. PT on Monday morning.

Mountaineer Micah Handell stands on the rock slab that fell from the rock face of Stawamus Chief on September 20, 2021. This image was taken during an ascent on August 24. (Micah Handell)

Bright said this persisted for 16 minutes.

“Both of my cats’ tails were really swollen and they were in panic so I knew something was going on,” she said.

Bright said that when she looks up at the chef on a full moon night, she usually sees the campers’ headlamps on top of the rock dome. Fortunately, the rain had driven the campers away.

Micah Handell climbs the Borealis section of the Zodiac Wall in August 2021. A month later, the massive rock pillar pictured here broke loose in a landslide. (Micah Hadell)

Mountaineer Micah Handell believes he was the last to climb a huge slab of angular granite before it sheared early Monday morning. He photographed himself on top of a rocky section on the Borealis Road on August 24, 2021.

But he said he quickly dismounted after seeing the deep, menacing crack between the boulder and the monolithic chief’s face.

“I was like, man, I’m glad I climbed this road before this thing fell,” Handell said.

Roberti warned against any further climbing on the chef’s rock face.

He said he wasn’t surprised people wanted to be the last to stand on a slab that threatens to fall.

“Yeah, people do all kinds of weird things,” Roberti said.

The Great Wall of Stawamus Chief is a popular rock climbing site near Squamish, British Columbia (Squamish RCMP)

Starting this month, a Simon Fraser University research group will use light sensing and ranging (LiDAR) and laser beams to study the rock structure and assess the safety and stability of its various sections. .

They hope to place seismographs to locate higher risk areas.

Paul Adam, head of citizen science initiatives at Simon Fraser University’s Center for Natural Hazards Research, said the “flakes” of rock falling from Chief Stawamus are nothing new and believes blaming him on climate change is a “stretch”.

But he agreed, climbing the monolith is for now.

“At this point, I would probably give it some time to settle down.”

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