Volcanic mountains

How the Mount Baker volcanic eruption would impact Metro Vancouver and the Fraser Valley


With widespread flooding in the Fraser Valley and critical mountain roads to the rest of the province and Canada cut off by washouts and landslides, November 2021 has been a tough month for British Columbia, but a reminder brutal that this corner of the world is prone to a number of natural disaster risks.

Although there have been repeated warnings of potential major flooding, what was considered unthinkable by some has happened. It is a difficult time to talk about it, but the public and policy makers need to be aware of the various inherent natural hazards and plan accordingly.

Using a telephoto lens, Mount Baker, located just south of British Columbia’s border with Washington state, certainly looks much closer than it actually is.

On a clear day, photographers have to put much more effort into capturing the “perfect shot” of this volcano from West Vancouver or the Strait of Georgia on BC Ferries, as it certainly doesn’t dominate the downtown skyline. of Vancouver in the same way as Mount Rainier backdrops Seattle.

Mount Baker is still quite close to Metro Vancouver, about 110 km from the city of Vancouver, and even closer to the Fraser Valley, only 23 km from Abbotsford.

Map showing the location of Mount Baker and the distance to urban centers in the Lower Mainland of British Columbia. (US Geological Survey)

Vancouver skyline

Panorama of Metro Vancouver, with Mount Baker in the distance to the left and Lions Gate Bridge and downtown Vancouver to the right. (Shutterstock)

Mount Baker Fraser Valley

View of Mount Baker from the Sumas Prairie in the Fraser Valley. (Shutterstock)

The proximity of this 10,781-foot-high stratovolcano – the youngest in the volcanic field in this part of the world – to one of Canada’s largest urban areas could be problematic. It is active, and with that comes the associated risks.

However, a Mount Baker eruption is unlikely to reproduce the same destructive force that Mount St. Helens did when it erupted in 1980, according to Professor Glyn Williams-Jones, co-director of the Natural Hazards Research Center of Simon Fraser University.

Mount Baker photographed using a telephoto lens from a BC Ferries ship in the Strait of Georgia. (Mark Donovan / Flickr)

Mount Baker

Close-up view of Mount Baker and the surrounding mountains. (Shutterstock)

He says pyroclastic flows, which are a cloud of particles and gases with temperatures between 200 ° C and 700 ° C and rapid speeds of up to 700 km / h, are unlikely.

The biggest concern with Mount Baker is lahars – the Indonesian term for destructive mudslides that have the consistency of wet concrete.

The potential for lahars is significant as Mount Baker has about 1.8 km3 of glacial ice, more than all other volcanoes in the Cascading Volcanic Arc except Mount Rainier combined.

Within hours of a volcanic event, lahars and flooding could occur in the Fraser Valley and parts of eastern Metro Vancouver.

Mount Baker in winter. (Shutterstock)

“It is plausible that if there was even a small eruption, a reactivation of the volcanic system, much of that snow and ice on top of the mountain would quickly melt and send mudslides through. the valleys all along the sides of the volcano, ”Williams-Jones told Daily Hive Urbanized. “This could have an impact on parts of the Lower Mainland. Efforts are being made to monitor this sort of thing. “

Slow lava flows similar to what happened at Lellani Estates on the Big Island of Hawaii in 2018 are unlikely.

Instead, the other major potential impact of Mount Baker is the fall of ash, which could wreak havoc on flight operations at Vancouver International Airport. This was the case in 2010 when transatlantic flights were significantly disrupted by the injection of ash into the jet stream from the Eyafjallajökull eruption in Iceland.

Mount Eyjafjallajokull Iceland

Mount Eyjafjallajokull erupted in Iceland on May 12, 2010. The ash plume ejected in the jet stream disrupted many international flights. (Shutterstock)

“Even a relatively small explosive eruption at Mount Baker with ash a short distance in the air could cause delays and cancellations for the airport,” he said.

“You are dealing with pulverized rock, it should not be confused with a substance like cigarette ash or wood fire ash. It is a combination of the rock from the volcano itself, which is fragmented and shattered into tiny particles. It’s basically magma, when liquid rock instantly turned into volcanic glass.

Ash stalls aircraft engines, destroys electrical infrastructure, creates dangerous driving conditions, and seriously damages the lungs when inhaled. People with breathing problems are likely to have problems and could fill emergency rooms.

Mount Baker

Sunrise with Mount Baker and the Lions Gate Bridge. (Shutterstock)

Another problem with ash is that when mixed with water it essentially becomes concrete and could threaten the structural integrity of weaker roofs.

“We see a lot of them in Indonesia and the Philippines, where simple timber-framed buildings would collapse. That’s because when you mix that ash with rain, it’s like you’ve just added three or four inches of cement to a roof. It covers it all, ”added Williams-Jones.

Williams-Jones says the last time Vancouver saw ash scattered over exterior surfaces was during the Mount St. Helens eruption in 1980. But the general pattern of the winds to the east and south of Metro Vancouver may mitigate some of the ash plume emitted from Mount Baker.

The city of Kagoshima, volcano in Japan

Winds bring ash to Kagoshima, Japan during an eruption of the Sakurajima volcano on June 3, 2010. (Shutterstock)

The previous eruption of Mount Baker took place in 1880, and Williams-Jones says it’s difficult to predict when it will erupt again.

He cites the example of the Calbuco eruption in Chile in April 2015 when the volcano’s seismometers provided a warning just three hours before the eruption, which scattered ash in nearby towns.

“Sometimes these volcanoes catch you off guard,” he continued. “These systems are complex and we try to predict these events, but we need basic monitoring. If we don’t have that, then we’re sort of blind.

Mount Baker

The male killer whale known as L95 Nigel surfaces off San Juan Island with Mount Baker in the background. (Shutterstock)

Every now and then, gas rises from the top of Mount Baker, but Williams-Jones says it’s mostly vapor from snow and ice sliding into the active crater.

Fortunately, Mount Baker is one of the most monitored and studied volcanoes in the United States due to its accessibility from urban areas and the relatively high level of funding for the US Geological Survey’s volcanology program as a result of the eruption of Mount St. Helens.

Two seismometers placed on the volcano by the US Geological Survey create a key early warning system for an impending eruption, as a swarm of tremors over a short period could be a sign that the magma is moving upward.

As a reminder of the power of Mount Baker, the last earthquake detected inside the volcano at the time of writing is a magnitude 1.1 quake striking at a shallow depth of 2.8 km, at 5:01 p.m. on Tuesday 16 November 2021.

This is the US Geological Survey’s simulation of the Mount Baker ashfall forecast based on a major eruption in the evening weather conditions of Thursday, May 17, 2018. The location of the ashfall is entirely dependent on the day’s weather:

Mount Baker

Forecast of ash fall from Mount Baker should a major eruption occur on the evening of Thursday, May 17, 2018. This forecast takes into account weather conditions such as wind direction. (US Geological Survey)

Mount Baker

Ashfall accumulation expected from a major eruption of Mount Baker on the evening of Thursday, May 17, 2018 (US Geological Survey)

This article was originally published in May 2018 and has been updated for republication in November 2021.