PEMBERTON, B.C. – For the second time in a week, a major rock slide has occurred on Joffre Peak, just east of Pemberton, B.C.
Earthquake seismologist John Cassidy says the latest slide happened at 9:03 a.m. on Thursday. In a social media post, he says it was significant enough to register on seismometers as far as 300 km away on Vancouver Island and was even larger than one picked up by seismometers early Monday from the same peak.
Here are some of the seismic recordings of yesterday's large rockfall on Joffre Peak (the second this week). It occurred at 9:03 a.m. PDT (May 16th). The seismic signals were well-recorded from Whistler to Vancouver Island to the British Columbia interior (> 350 km distance). pic.twitter.com/Gy9IfzwfJ6
— John Cassidy (@earthquakeguy) May 17, 2019
Hydrologist and geoscientist Drew Brayshaw, who has climbed extensively in the area, says it appears the first slide sent a flow of debris more than four km down Cerise Creek, east of Joffre Lakes Provincial Park.
He says both slides occurred on the north face of Joffre Peak, which faces away from the provincial park and that neither slide would threaten the park or its well-known turquoise-coloured lakes.
Brayshaw says as soon as he saw the scar of yesterday’s landslide, next to one from earlier this week, he realized there’s the potential for further trouble.
“That strongly suggests that the next buttress, over on the face of the mountain to the left, is probably, I would say, more likely than not, going to fall off as well and the question is just when,” he says.
“This is a peak which is one of the crown jewels of mountaineering in southwest BC and is popular and beloved by a large number of people. It’s also obviously one where there’s potential for a landslide to run out and reach the highway, and so there’s clearly a lot of people concerned about public safety as well,” Brayshaw says.
The ministries of highways, environment and forests, as well as Emergency Management BC have not yet commented and the Squamish-Lillooet Regional District says it is up to the provincial government to order a geotechnical assessment of the area.