Meager slide: One year later

Local officials still hopeful for early detection system

Patrick Smith won't likely ever forget the early morning hours of Aug. 6, 2010. In fact, it's a time that the former Whistler resident said he thinks about almost daily.

At approximately 3:30 a.m., Smith and a group of three friends had just reached a campground near the Mount Meager complex, about 60 kilometres northwest of Pemberton. They only had enough time to set their bags down before hearing a huge crack ripple through the sky.

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What they heard was a glacier breaking apart - the trigger to the Mount Meager landslide that focused the world's attention on the Pemberton Valley for a couple of tense days last summer.

Next, the group heard what sounded like a train approaching through the pitch dark of night, and they hardly had time to finish arguing about what they were hearing before trying to drive up the forest road to safety. But they were quickly met by a "wall of water" ahead on the road and a downed tree blocking the road in the opposite direction.

"The moment when we were all sitting there and you can still hear the mayhem breaking loose and everything coming toward us, that was the rock bottom moment," Smith told The Question on Tuesday (Aug. 2). "We felt like we were out of options and we were just waiting in the dark for it to come up on you."

Thankfully, Smith's party and several other campers in the area were rescued when search and rescue helicopters scanned the area for anyone in trouble. But the Meager complex has been the focus of much more surveying since.

Rick Guthrie is a leading expert in the field of landslides and was working as a regional geomorphologist for the Province one year ago. He said he was about to board a ferry to Vancouver when he started learning what had happened on the Meager complex.

"When I've dealt with larger events, I've had to travel a great distance to see them," he said. "All of a sudden, really not much further than that ferry ride away, is a world-class landslide. This is what I've been doing for 15 years, so it was pretty exciting."

Instantly, the slide was recognized as one of the largest Canada had ever seen.

When the event first occurred, experts estimated that the volume of debris totaled 40 million cubic metres, making it the second-largest landslide on record in Canadian history behind only the 1965 Hope landslide.

However, the Meager estimate has now grown to more than 48.5 million cubic metres, said Guthrie, putting it in the running for largest all-time.

"That puts it on par with the Hope landslide, which was measured at 48 million cubic metres," he said, noting that some prehistoric events would come in with greater volumes.

"That does make it slightly bigger than we originally estimated in the field and we've spent a ridiculous amount of effort trying to be as accurate as possible with the volume.

"From an historical perspective, it's almost unprecedented in Canada. We have very, very few examples. We have the Frank (Alta.) slide in 1903, the Hope slide and this one."

The images that began to appear from helicopter fly-bys in the hours following the rock avalanche were compelling. Some of the figures that can now be associated with the event are simply staggering.

When the debris gave way, it traveled at an average speed of 64 metres per second - or 230 kilometres per hour.

"That's about the speed of a Formula One race car," said Guthrie. "As it came down Capricorn Creek and hit the Meager Creek valley wall, it ran up 270 metres in height, and amazingly, it split and ran upstream almost four kilometres."

While the Meager slide wasn't the largest Guthrie has ever studied, as he noted one in Russia in particular approximately twice the size, he said it was still a bit of a shock to see the devastation it caused.

"We didn't really know how large it was initially," he said. "We knew it was huge, but when we got up in a helicopter and came around the corner to travel almost four kilometres before we hit the Capricorn-Meager confluence and be able to look fully up Capricorn Creek and see it had completely wiped out that watershed - it was a phenomenal event."

Guthrie is no longer working for the Province but has spent much of the last year working on a case study that contains contributions from multiple universities and several other experts on the subject. It's expected to be published in the coming months.

But in the meantime, Guthrie is hoping to provide a condensed report to both the Province, Village of Pemberton and the Squamish-Lillooet Regional District (SLRD) before the end of August.

He said the team of scientists working on the study will be making some recommendations to the different levels of government, though he said he couldn't reveal what all of them are until publication. But Guthrie did say there are important things for residents of the Pemberton Valley to learn from last year's slide.

"There was a paper that came out in Georisk a couple of years ago that gave some information about what kind of hazards and risks (the area) might be presented with, and then a short time later we were faced with the coincidence of one of the larger landslides we've ever had occurring on that same slope," he said. "That's given us the ability to go back and look at what's reasonable to be done here and some of it will be useful to the community if they want to take it on."

The paper Guthrie is referring to was written by multiple experts in the field who are also co-authoring the forthcoming Meager slide study. It was presented to the SLRD in 2008.

Squamish's Pierre Friele was the lead author on that report and noted the danger for residents in the area. Friele told The Question days after the slide that he felt some kind of early warning detection system was needed.

SLRD emergency management coordinator Ryan Wainwright said that discussions about such a system have been ongoing, but "not as much progress as we would have liked" has taken place so far.

A provincial government spokesperson said a weather station was installed in the area just prior the slide that can predict conditions optimal for a slide, but local officials want a way to monitor rapid changes in water levels.

"I'm not sure where that's fallen off, but what we would like to see at a minimum is getting water gauges in place that can start communicating with us," Wainwright said.

"We're talking about an enhanced water measurement system that will let us know at a certain point below Meager whether the flow in the Lillooet has dropped precipitously over a certain period of time.

"We could get a landslide in the middle of the night and it probably wouldn't be for a couple of hours until that water really hits the gauge and drops off that we know we have a problem up there."

Wainwright said it was about three hours after last year's slide took place that local officials started to learn of it, but they were somewhat lucky to find out that quickly because there happened to be people in the area who called it in.

"Guys who were headed up to work the pumice mine up there ran into a big wall of debris and couldn't go any further," he said. "So it was within about two or three hours, and that's pretty good considering there's not a lot of population up there and not a lot of traffic on the road."

What was also lucky was the effects noticed in the Pemberton Valley. As water began to pond and form a lake behind the slide site, the potential existed for the flow to burst through the debris in a giant wave, which would have caused a major flood and devastating effects on Pemberton and Mount Currie. Instead, the water cut a channel through the debris and came through at a manageable pace.

Still, the risk was enough to issue evacuation orders in the valley, and Wainwright said that he was very pleased with how efficiently word of the danger got out to residents through government co-operation.

"We had a really good experience on the response side for that event," he said. "The three jurisdictions that were impacted - the Village of Pemberton, the SLRD and Mount Currie - really got to see the proof of what it means when we plan together and exercise together. We were able to make sure the messages that were coming out to our residents were the same for all three jurisdictions, and the actions we were taking as local governments were in line with one another.

"That model that sort of had its first day out of the barn during Meager has persisted, so that when we get an event in the Pemberton Valley now it's all three of us working together."

That partnership may need to respond to another such event in the future, as Guthrie said the chance of more activity in the Meager complex is high enough to cause concern.

He said scientists working on the current study have looked at all slides recorded going back 150 years to project the probability of further large slides.

"The probability that we would see a landslide off the Mount Meager complex larger than 10 million cubic metres - keeping in mind that (last year's) was almost 50 million - in a 50-year period is 61 per cent," said Guthrie.

"In 50 years, a lot can happen in terms of development and how we plan our communities in the long term. Those are things we would definitely want to be aware of."

The Pemberton Valley Dyking District posted a Large Woody Debris Assessment (LWDA) of the Lillooet in June. It concluded that the hazards existing from that type of debris "are not as bad as might have been expected given the size of the slide."

More studies on the river system are likely to come. Local officials are hoping to complete a post-slide gravel assessment while the Province is going to look at the road system in the area "from an erosion control perspective," said a provincial spokesperson.

Despite the Meager complex's remote location, Guthrie estimated that the slide caused more than $10 million in damage. Six kilometres of forest service road was buried, several vehicles and pieces of construction equipment were lost and two bridges wiped out, according to the LWDA.

The Meager Creek Hot Springs could be cut off forever. The Province has closed the site indefinitely, but you couldn't get up to the area if you tried. A provincial spokesperson said a lake now sits where there used to be a 70-metre long bridge, so the hot springs are inaccessible.

But things could certainly have been much worse. Just ask Smith.

"We felt extremely lucky to be exactly where we were at every minute for what went on," Smith said. "Everything added up for us to be in the right place at the exact time. If we had been a couple minutes later going through there, we could have been 500 metres or a kilometre down the road where it got totally wiped out."

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