WHISTLER -- Picturesque Pemberton in the Lillooet River Valley is living in the shadow of disasters.
A new study shows that three massive landslides over the past 6,000 years have travelled 70 kilometres down the valley from the side of Mt. Meager, a dormant volcano.
"A landslide as large as the largest that has occurred . . . probably would generate a debris flow that would destroy much of the development in the Lillooet valley, and if not preceded by warnings, would kill hundreds or possibly thousands of people," says the study.
"We don't want to panic people," said study co-author Prof. John Clague, chairman of the Simon Fraser University Centre for Natural Hazard Research. "But the risk is enough that something should be done."
There have been several large landslides in the last century, with one in 1975 killing four people.
The study suggests that Pemberton and the Squamish Lillooet Regional District consider installing an early warning system. If a slide occurred it would likely take some time to flow down into the valley, giving enough time for an evacuation.
There is no way of knowing when disaster might strike. The landslide could happen next week or in 1,500 years, said Clague.
About 2,517 people live in Pemberton, and a total of about 4,000 live in the possible path of a giant slide. Pemberton is one of Canada's fastest-growing communities, with its population going up 30 per cent between 2001 and 2006.
Clague said Mt. Meager is considered the most unstable mountain in Canada for landslides.
"We were wanting to document the history of the valley in that area and what we found there was quite startling," he said.
"We found evidence of what we call . . . volcanic debris flows that had travelled all the way from Mt. Meager . . . the entire distance down the valley to a populated area.
"So we began to think in terms of the very serious risk to the community . . ."
There are no provincial or federal standards for how much risk people can be exposed to from naturally occurring hazards. But using protocols from other nations such as the U.K. and Australia, Clague said, the researchers found the risk from Mt. Meager to be "unacceptable."
Clague said he and his fellow scientists, some with the federal government and others private consultants, felt compelled to share their findings with the Village of Pemberton and the SLRD. The study, which is available at www.slrd.bc.ca, was submitted to both last week.
The B.C. government downloaded responsibility for determining and enforcing levels of acceptable hazard to local governments in 2004.
The district has already sought a legal opinion on its liability, administrator Paul Edgington said yesterday. The district has taken out ads in local papers to alert the public to the study, which will be discussed at its meeting Monday.
"I think it is something we have to assess, understand and then look at responsible steps to address it or mitigate it," said Edgington.
Pemberton Mayor Jordan Sturdy said council is considering an early warning system.
"We will meet with the authors [of the study] and consider what the options are and it may be that there is a possibility of looking at early warning type of technology," he said.
Sturdy noted that people live with natural hazards all over the Lower Mainland.
"There is a risk with developing a building in Richmond, with its tidal surge and liquefaction, so there are risks all over the place, so you have to keep it in perspective," he said.
"Any future residential development in this community will be for the most part off the valley floor [due to the risk of floods] and up on the hillside -- that is what is in our official community plan and in the regional growth strategy."
Asked if he felt the slide risk would affect development, Sturdy said: "Generally, no. And the reason I say that is because the area that is most at risk is the agricultural land and we have no intention of developing the agricultural land."
Nick Batistic, an account manager with Pemberton Insurance Corp. in Vancouver, said landslides are rarely covered by insurance.
"It would be very wise for people to research thoroughly the geography of the area and let that guide them as to where they want to put their investment money," he said.
"It would be a 98-to-99-per-cent certainty in most cases that coverage for landslides caused by the nature of what this report states would not be responded to by insurance."
clareogilvie@telus.net
From: Canada.com