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Risk rising

Receding glaciers are making Pemberton-area volcano Mount Meager less stable than ever before

On July 21, 2016, a local helicopter pilot was flying a group of biologists to the mountains outside of Pemberton, where they planned to conduct a survey of the mountain goat population.

But the pilot—who happened to have a background in geology—spotted something unusual as they whizzed past the Job Glacier on Mount Meager: three holes in the glacier below that were spewing gas.

He knew enough to report the sighting of what turned out to be fumaroles, openings in a volcano from which hot steam and gas emerges.

The discovery quickly made its way to the desk of Dr. Glyn Williams-Jones, a professor of volcanology at Simon Fraser University (SFU) who also serves as co-director of the Centre of Natural Hazards Research, which brings together researchers from the University of British Columbia (UBC) and SFU. Researchers knew that fumaroles likely existed on the mountain—there had been reports of a sulphur-like smell near the mountain for years, not to mention hot springs in the area—but now, with the glaciers retreating, it seems they had emerged from beneath the snow and ice.

"The (big) issue with Meager is landslides, but landslides off an active, though dormant, volcano," Williams-Jones says. "We have gas coming out, so we can't say it's extinct."

A month later, Williams-Jones, one of his graduate students and Dr. Kelly Russell, a UBC professor who has been studying Meager for 30 years, were on their own helicopter ride up the volcano to study the new discovery. "I went in with gas sensors," Williams-Jones says. "All we were measuring was H2S (hydrogen sulfide) and CO2. (They were found at) very high levels. H2S is very toxic, but the tricky thing is (determining) whether it's an immediate hazard ... It was a long shot, but if a climber (capable) enough to climb up there went all the way into a crevasse, they would drop dead. That was the concern."

According to the situation report released after the study, the fumarole melt caves are 30-by-30-by-30 metres, and "likely represent a fumarole field—an area of hot springs and gas vents—beneath the ice."

Technicians, who also flew up that day, installed a temporary seismic station to help Natural Resources Canada monitor the area for hundreds of small, tell-tale earthquakes that would occur prior to an eruption.

But fast-forward two years and that station has been removed. "In an ideal world, we'd have a dozen seismometers around the volcano," Williams-Jones says. "We don't currently have any on any volcanoes in Canada."

The problem: installing an instrument that could survive a winter on top of Meager would cost over $30,000. "There's new technology coming," Williams-Jones adds. "It's a matter of years, but you want it now."

The likelihood of Mount Meager erupting might be low, but scientists who have studied the volcano say that, thanks to global warming, the chances of a catastrophic event of some type occurring is on the rise.

According to a 2018 study called Landslides and glacier retreat at Mt. Meager volcano: hazard and risk challenges, written in part by an SFU PhD student, Gioachino Roberti, "The risk of loss of life was deemed unacceptable in 2008. Today, in a first-order estimate the risk has increased."

After the fumaroles were discovered, Williams-Jones says the Squamish-Lillooet Regional District (SLRD), Emergency Management BC and Natural Resources Canada took it "very seriously."

The risk is partly due to melting glaciers changing the water flow system and destabilizing the area further, as evidenced by the 2010 landslide at Meager, the largest in Canadian history. The recent study found that the volcano has lost around 1.3 cubic kilometres of glacier cover since 1987.

"It's a big mound of rotten mountain," Williams-Jones says. "I'm absolutely not saying the sky is falling, but people need to be aware that this area is unstable and these things can happen, essentially almost instantly. We need to be doing a better job monitoring."

The last eruption

Mount Meager has long held special interest for Canada's small pool of volcanologists because of its distinction as this country's most recent explosive volcanic eruption, some 2,400 years ago.

While that might seem like an unimaginably long time ago, for those who study the geological history of the planet, it's considered extremely recent.

Russell, who has studied that period in Meager's history, says the eruption would've been slightly smaller than that of Mount St. Helen's, the Washington state volcano that erupted in 1980, killing 57 people. "It started off explosively with the eruption column building up 15 km above the edifice," he says. "The plume built up over the volcano and erupted for ... hours. It dropped ash as far away as Jasper, Alta. The deposits are very thick at the foot of the volcano, but they thin and become fine as you go away from the volcano."

Researchers have also found pyroclastic flows down Lillooet Valley. "They're super hot, gas-charged blocks the size of small cars. High energy, fast moving, hot," Russell says, explaining the flow's content. "They move like a mudflow or lava at super-high speed. Those things are all contained in the paleo Lillooet Valley. The valley captured them and made them go down the valley."

After those pyroclastic flows collapsed, the volcano's output turned from explosive to effusive, meaning thick, viscous lava started to flow, travelling down Meager's steep slopes.

"They started falling apart because the slopes were so steep," Russell says. "They fell apart explosively, setting off a pyroclastic density current. These things filled up the valley with 90 metres of garbage that blocked the Lillooet River. The river built up a lake two or three kilometres upstream behind a dam."

That dam ultimately failed and caused a "cataclysmic flood" that moved "garage-sized blocks of the dam downstream six or seven kilometres," Russell adds.

While the area was a trading and hunting route for the Lil'wat people, there's no record or stories of any of them being impacted by the eruption.

Another heartening piece of news: if the same magnitude of eruption were to happen today, Russell says the biggest risk to residents would be flooding.

"(It would) be totally catastrophic to the power grid and people in the (immediate) area, but the big impact would be on the Lillooet River, and the fact that it flows through Pemberton," he says. "If it was big enough, if it was winter and caused a lot of melting, you'd have a huge amount of runoff, a huge amount of debris, potentially causing floods in Pemberton."

It's notoriously challenging to study the history of such "young volcanic" deposits, he adds, because they're unconsolidated and erode easily. In fact, his team determined the date of the last explosion by carbon-dating burned logs in the area.

"The fact that it's an explosive event and the youngest makes it worth studying, I'd say," Russell adds. "Some of the deposits we've been working on there are unique worldwide in their characteristics. I've taken a number of international field trips up there and no one has ever gone away disappointed."

A hotbed for research

Volcanologists want to make one thing clear: they're not worried about Meager exploding the way, say, the Kilauea volcano in Hawaii Volcanoes National Park did earlier this year.

The probability of a catastrophic explosion is low, but retreating glaciers are contributing to the possibility that it could happen. "We don't really know," says Roberti, a PhD Student in Simon Fraser University's Earth Sciences Department. "We have just one eruption we know of (more than) 2,000 years ago. But we know there are many larger landslides and the hazards from the landslide are higher than hazards from the eruption. Then, secondary to the landslide itself is a major hazard that can go from Meager to Pemberton, (but) the landslide can also trigger an eruption."

Roberti began studying Meager after the 49-million-cubic-metre landslide in 2010—which sent debris 7 km down Capricorn Creek to Meager Creek—with a focus on the landslide risk. But, more recently, he's gained attention for his work studying glaciated volcanoes like Meager and how, exactly, retreating glaciers are impacting their stability.

Meager is made up of volcanic rock, which is weaker than other types of rock because it forms so quickly, adding another layer to the hazard risk assessment.

"The (glaciers) are melting. The trend is retreating ... When you remove the ice (from a slope), you're removing a protective layer. You see an increase of landslide and rockfall. For the 2010 landslide, the glacier was retreating. The slope failed during the hot summer. Water was coming from the melting ice, it was entering the slope through the cracks, (and) fracturing the rock. You can imagine a sandcastle on the beach and the sand is too wet—the castle won't stay up. When you add water, the castle goes down, collapses," Roberti says.

His study from earlier this year further explains the risk. Researchers documented 27 large, potentially unstable sites; 17 of which have recently become ice-free. Furthermore, 15 of those slopes have a large enough volume that, if they were to fail, would affect infrastructure near the volcano. (Currently, there are two hydropower plants as well as forestry work happening in the surrounding area.)

"In view of the history of landslides on the massif, including the 2010 landslide, future collapses are certain," the report read. "This inevitability must be considered in view of the recent increase in infrastructure near Mt. Meager and the increase in population-related infrastructure in the Pemberton area."

To that end, the report advocates for the use of InSAR-based slope monitoring—a radar technique that can measure surface deformation to a very small degree—as well as an early warning system on Mount Meager to "mitigate the high level of risk."

"It should be taken seriously," Roberti says. "I've been writing papers and the people I've been working with have been writing papers the last 10 to 15 years, proving with scientific data, that the risk of life loss from a landslide from Mount Meager is unacceptable by international standards ... When (the risk is) a landslide from a volcano and the average citizen doesn't even have an idea there's a volcano there, the public authority should take care of trying to minimize this risk."

According to information from the Pemberton Valley Dyking District (PVDD), there is a 96-per-cent probability of a landslide from Meager greater than 500,000 cubic metres happening in the next 50 years. A 10-million-cubic-metre landslide is 61 per cent likely to happen in the next 50 years and 85 per cent likely in the next 100 years. (For comparison, remember Meager's 2010 landslide was 49 million cubic metres. Frank Slide, perhaps Canada's most famous—and deadly—landslide, was 44 million cubic metres.)

While the landslide risk is well documented, the risks that could arise from an eruption are less clear. That's what SFU MSc student Rachel Warwick is in the midst of studying.

More specifically, she's developing a volcanic hazard map as a final product of her research that she'll be able to turn over to local emergency management teams for real-life use.

"There has never been a hazard map or assessment created for any Canadian volcano," she notes. "The fact that we have Canadian volcanoes is so unknown to so many people. Just the fact that I get to be at the forefront of that type of research is amazing."

Her assessment is based on a few established facts about Meager: its composition, and what the general scale of an eruption would be. From there, she's looking at three scenarios, ranging from "worst case" to "not so bad." Then, she's examining four hazards that arise from an eruption, including the ash distribution, lava flows, lahars (volcanic-derived mudslides), and pyroclastic flows.

"The map and assessment is derived from numerical models," she explains. "(I) looked into different models out there and what's accessible and easy-to-use for the four hazards. Using those models, I started looking at the lahars and ash distribution so far from looking at computer models ... We know the scale of the eruption Meager had over 2,000 years ago. That's one scenario we're going off of."

While the map isn't complete—Warwick is entering the second year of her masters—she's determined the outcomes of a few scenarios so far. The ash distribution, for one, largely depends on wind direction. There are, however, some cases where the model shows ash reaching as far as the Vancouver airport. "That's a rare case, but it's interesting that wind patterns (can do that)," she says. "There could definitely be an impact. Sometimes the models do show it going over Pemberton. I would think air quality in general, whichever way the wind is going, would be diminished in Pemberton."

But, overall, "what I'm finding is you need a humungous amount of failure to reach Pemberton or go into Lillooet Lake," Warwick adds.

Even though her early models show a potential impact on Vancouver in some scenarios, Warwick says many people in the city have no idea that many of the Coast Mountains are actually volcanoes—let alone that Meager is an active, dormant volcano.

"People are so unaware that you have something that's so epic and beautiful and crazy," she says. "So often people are surprised—even people in my Earth Science department don't realize that (the mountains are volcanoes)."

On alert

There is one system in place to alert the Pemberton Valley about a future landslide at Mount Meager. More specifically, the Lillooet River Early Warning System will detect a sudden rise or drop in water level, which is an indication that a landslide has blocked the river upstream or, conversely, that a blockage has suddenly released.

The system involves two sensors. One is mounted on the Hurley River Forestry Bridge and the other is in the water. While the province agreed to fund the initial $30,000 to install the system in 2014, four years after the epic landslide, the PVDD has overseen its operation since then.

Steve Flynn, operations and maintenance manager for the PVDD, has been tethered to the alert system over that time, essentially 24 hours a day, seven days a week.

"In the first four years we had many, many, many false alarms," Flynn says. "It was because we can adjust the sensitivity on the sensors. If it's too sensitive you get many false alarms because in the winter you could have a large chunk of ice go by that looks like the (water) came up a metre. Or an ice floe can break up and float away. Now it looks like it dropped a metre. We've been fine-tuning the sensitivity on it over the years ... We've got it pretty well figured out now. If the alarm goes off, it's something going on."

Until last year, Flynn would have to get out of bed—or abandon whatever he was doing—and head into the potential heart of the flood to check the bridge if the alarm went off. Now, there's a camera in place. (Flynn also notes there's a system installed to catch any potential saboteurs after the system was twice vandalized.)

"If you think about it, these events generally don't happen on a beautiful sunny day at 8 a.m.," he adds. "It's stormy nights and pitch black and you can't get an aircraft in the air and you can't get to the site to analyze it."

While responsibility for the system is technically shared between all the jurisdictions that could be impacted by a massive flood—alongside the PVDD that includes the Village of Pemberton (VOP), the SLRD and the Lil'wat Nation—there was a shortlived dispute over how ongoing costs would be shared for maintenance and operation of the warning system going forward.

VOP council initially resisted committing to paying costs indefinitely, but decided to go forward with the cost-sharing arrangement after the PVDD sent a lengthy letter outlining the system's importance.

As of this month, the other governments have also agreed to share monitoring duties going forward. In the letter to council, the PVDD highlighted an instance where Flynn was away on holidays out of country for a week and turned monitoring duties over to the partners—only to learn false alarms were ignored in his absence.

"Some people in the area were complacent—or they thought that, 'Maybe it's someone else's problem. Someone else will look after that' when in fact local government, under the Local Government Act, have a responsibility to the people in their jurisdiction to address safety concerns," Flynn says.

However, he adds, "I think that's past tense now. Everyone has gotten onboard and realizes that it's a very important tool. It deserves respect and everyone seems keen to get onboard."

The people monitoring the system began training on Sept. 4 and, with funding in place, "it should be smooth sailing now," Flynn says. "It's a good news story."

Monitoring at the river level might be in place, but there are still more options for monitoring on Mount Meager itself that would potentially buy authorities more time to prepare residents for a landslide or eruption.

The problem is, with the province dealing with forest fires, floods and more immediately pressing natural disasters, it has been a challenge to secure funding.

"What would be great is to know years, weeks, hours in advance that something is about to happen," says Ryan Wainwright, emergency program manager with the SLRD. "I think the elected officials in the area have a very complex understanding of the issue and I think that there is will to continue raising that with the province and federal bodies. These hazards exist throughout the entire corridor—from Vancouver to Lillooet and beyond. We know they're there, we've studied them, now we understand the risk in a very detailed way, so we need some assistance to continue living with this risk."

Wainwright himself understands the risk the volcano presents; his first week on the job in 2010 was the week of the Meager landslide. "It was intense," he recalls. "The first indication was a drop in river level, which happens quite precipitously—that means three or four hours before something happens."

Ultimately, he made the call to evacuate the floodplain, worrying that a build-up of water in the river could release "explosively," he says. "It can send a wall of water and debris all the way down to the lake and beyond."

It takes eight to 10 hours—or longer—to evacuate. Luckily, it all unfolded smoothly.

"That night up at Nairn (campground) there were people sleeping in fifth wheels, high points had people camping on lawns," he remembers. "But the next day it was clear the pressure behind the (barrier) was going to release gradually."

Somehow there wasn't a single injury sustained in the whole ordeal. "It was a huge relief," he adds. "Once we broke through, it was a fascinating learning experience for me—not just how this community responds to that kind of thing, which is well, but that there was this unique (hazard) that wasn't the first thing that springs to mind when you think of Pemberton."

monitoring the future

For his part, Williams-Jones is hoping to raise awareness about the risks at Meager and push for government funding for more monitoring. "When it fails, it's gone," he says. "Part of me promoting this aspect of the story of Mount Meager to push for more monitoring."

For now, he has at least one group of citizen scientists visiting the volcano who plan to report back with observations.

Mountain Skills Academy and Adventure, a local outdoor adventure guiding company, has tenure in the area. Occasionally, they've guided high-end tours to Job Glacier to view the fumaroles, something owner and operator Eric Dumerac is hoping to do a little more often going forward.

(The public should note it's not possible to hike up Mount Meager and that exploring the potentially deadly fumaroles without a guide is highly discouraged.)

"To me, this is one of those places that, when I go there, every time my jaw drops," Dumerac says. "It's a really, really cool thing."

He's guided scientists in the area, donating his company's services to learn more about it. He's also reached out to Williams-Jones about offering more frequent reports.

"In the high season (in summer and winter), I could see us going three times a month," he says. "That's 18 reports that they otherwise would not get ... My company and I could be citizen scientists. I'm keen on doing that. All those clients that come up (could) help facilitate that. That's my vision."

Williams-Jones, meanwhile, is currently in the process of submitting a grant proposal to put sensors along the Lillooet Forest Service Road up to Meager that could also serve as an alarm for a landslide. Linking that to other sensors could allow scientists to "listen" for slides.

"We know where those landslides are going to travel," he says. "They're going to come down through Pemberton Meadows, so there are engineering things that can be done to at least reduce the impact on, say, Pemberton, putting up either damming-type systems called sabot works that slow things down or rigid structures that can minimize flood, things like that. But we need to be doing the research and doing the assessments to actually realize this is a serious, serious thing. It's not fear mongering, but ... this happened before, it's going to happen again."