After a devastating flash flood killed over 1,000 people at the Nepal-Tibet border last month, we wondered if a similar event could occur in B.C.
We spoke with Joseph Shea, a professor of environmental geomatics at the University of Northern British Columbia (UNBC), and asked him about both the incident in Nepal and B.C.’s glaciers.
He said Nepal’s flash flood was caused by both a landslide and an ice avalanche, with the latter the result of a large portion of a glacier collapsing.
The result of the devastating flash flood in Nepal. (Azwadafraz/Shutterstock)
Because the Himalayas are extremely steep, the friction of the glacier falling caused the ice and snow to melt instantly.
“And as far as we know, that’s the source of all the water and mud and rock that then got channelled into these very narrow valleys. So it’s really steep topography up there, and the flood wave just built up in elevation and speed, and that’s why it was so devastating,” Shea told Daily Hive on a phone call.
He said that this was “almost an unimaginable scale of disaster.”
While climate change is transforming B.C.’s glaciers and there are risks associated with this, Shea doesn’t think we will see a similar event to Nepal.
“We have a very different set of topography and factors that influence a glacier collapse and massive landslide like that.”
The Himalayas are relatively young compared to the mountains in B.C., meaning they are taller and more unstable, Shea explained. Large events — like what happened in Nepal — are occurring in younger mountain ranges with “really high elevations.”
But B.C. glaciers are still changing
However, B.C.’s permafrost, like in Nepal, is melting due to climate change heating up the planet.
Shea said permafrost “goes fairly deep into the mountainside” and is “basically like a glue that can be holding some of these mountain pieces together.”
“And if you thaw it enough, and then you sort of wedge another bit of ice in, it’s just enough to make it topple,” he said.
“Rock falls and landslides are going to become more frequent and common as permafrost thaw moves upwards in the mountain regions.”
He said we’ve already seen some rockfalls that could possibly be attributed to thawing permafrost, like the Mount Meager landslide in 2010, the Elliot Creek landslide in 2020, and the Whistler rockfall earlier this year.
Further, climate change is also melting B.C.’s glaciers, causing them to retreat and leaving behind steeper and more unstable slopes.
“If you imagine a glacier extended far down a valley, these steep walls are sort of pinned in by the ice. But as soon as that ice retreats back up the valley, all of a sudden those steep walls can collapse.”
This further increases the risk of landslides and rockfalls.
Is there anything we can do?
We asked Shea what we could do about climate change melting glaciers and permafrost.
“When you’re in a hole, the first rule is to stop digging,” he said. “So it really is a global effort to reduce greenhouse gas emissions.”
But even if all GHG emissions stopped today, glacier retreat would still continue due to how much the climate has already changed.
“Because [glaciers are] out of equilibrium with their current climate, and because climate is continuing to warm, they are definitely going to continue to retreat.”