The threat of a glacial lake overflowing and potentially sending a torrent of meltwater and debris rushing toward homes has become an annual fear for people living near British Columbia’s Place Glacier.
For the third year in a row, residents of rural communities roughly 180 kilometres northeast of Vancouver have evacuated their homes as water levels at the glacier’s edge have reached a perilous level.
Like many of Western Canada’s more than 15,000 glaciers — and many more around the world — the Place Glacier is retreating rapidly because of warmer temperatures and changing weather patterns driven by climate-harming fossil fuel emissions.
That is raising the risk for the 15 million people worldwide who live downstream from glacial lakes, where it’s not a matter of whether a lake will overflow, but when — and how destructive the event might be. Experts say governments, scientists and communities need to collaborate to protect people and their homes.
“It has to be a wake up call that climate change is here and how we adapt, mitigate, and come together is really going to dictate how we continue to face these hazards and vulnerabilities,” said Rodrigo Narro Pérez, an assistant professor in the School of Earth, Environment and Society at McMaster University in Hamilton, Ont.
People living in a small community northeast of Pemberton have been ordered to leave immediately.
The Squamish-Lillooet Regional District says there is an imminent risk of flooding.
How do glacial lake floods happen?
Most glacial lakes around the world are held back by natural dams known as moraines, which are made of rock, sediment and ice deposited by a glacier.
Glacial lake outburst floods (GLOFs) happen when an unstable moraine breaks open or accumulated meltwater rises above the barrier because of rapid snowmelt, heavy precipitation or a landslide.
What makes the lake at Place Glacier different is that it sits atop the glacier’s edge, forming what is known as an ice-marginal lake, said Dan Shugar, who runs the Water, Sediment, Hazards and Earth Surface Dynamics, or waterSHED, Lab at the University of Calgary.
“The glacier itself is acting as the dam,” he said. “The dam can actually reform year after year so that ice can kind of heal itself, if you will, and that lake will just keep reforming.”
As meltwater accumulates in the basin behind the dam, it eventually reaches a depth at which it begins to drain beneath the ice wall where it meets the bedrock, explained Brian Menounos, a geography professor at the University of Northern British Columbia.
He told CBC Vancouver’s The Early Edition that the water is now somewhere between the depths at which outbursts occurred in 2024 and 2025.
The 2024 event released an estimated 100,000 cubic metres of water and sediment, flooding downstream properties along Gates Lake — one of two areas currently under evacuations orders.
It’s not an immediate rush of water, Menounos said. But as the water begins to flow and further opens the ice dam, the lake level drops faster and more water rushes out.
He said monitoring sensors at the site should alert scientists and officials several hours before that happens. A GLOF event typically unfolds over one to two days.
How can communities be protected?
Shugar said the Place Glacier will continue to produce outbursts for the “foreseeable future,” until the ice retreats beyond the basin or a channel forms that prevents water from accumulating.
While GLOFs are a natural process, they are becoming a growing threat to communities as climate change affects glaciers around the world, particularly in the Himalayas and the Andes.
Steps have been taken to mitigate the risks in parts of those regions, Shugar said, including building concrete spillways or excavating channels to lower water levels — efforts that can cost millions of dollars annually.
Shugar said he is not sure such measures would be feasible at Place Glacier. Artificially draining the basin would likely have to be repeated every year for decades, and it is by no means the only lake on the expansive glacier.
B.C.’s emergency management ministry has already rejected a proposal to use explosives to drain the lake and prevent a third outburst flood, saying it was not a “commonly used approach” and could have unforeseen effects.
The best tool, Shugar said, is effective monitoring so people in the potential path of an outburst flood receive ample warning.
Knowing the volume and temperature of the water in the lake can help determine how significant a GLOF might be, Menounos said. That information can then be shared with district and provincial authorities, First Nations and residents in the area.
He pointed out that Place Glacier is one of only two glaciers federally monitored among the thousands in the province.
Some residents northeast of Pemberton have been ordered to leave due to an imminent risk of flooding from a nearby glacial lake. Brian Menounos, a University of Northern B.C. geography professor and Hakai Institute affiliate scientist, has been monitoring the glacier and said climate change has made flood risks like this more common.
How is climate affecting glacial lake floods?
Menounous and his fellow researchers found glaciers in B.C. and Alberta suffered their second-greatest loss on record in 2025 — an estimated 30 gigatonnes of ice.
Narro Pérez said the overall rise of global surface temperatures has contributed to melting in several ways.
It’s not just a matter of hotter weather melting ice. Changing weather patterns have also brought lower snow accumulation and more precipitation falling as rain at certain times of the year, reducing the formation of new glacial ice.
“That means we’re going to continue to see the number of glacial lakes increase, the volume of those glacial lakes increase, and in turn, the vulnerability and risks of those communities that are downstream of the lakes increase,” he said.
Shugar said this points to the need for more government funding to increase monitoring of Western Canada’s glaciers as human-caused climate change accelerates melting.
“We need to be reevaluating the hazards and risks every couple of years, probably, in these mountain environments where the landscape is changing so much, he said.
Some Canadian scientists are trying to predict how fast glaciers are melting by collecting data on top of Place Glacier, an ice field that’s quickly disappearing near Pemberton, B.C. Radio-Canada’s Camille Vernet put on her crampons and followed the team for two days.
