Industry News
The Trans-Canada Highway remains closed through Rogers Pass as an unusual combination of heavy rain and warm temperatures has destabilised the snowpack, triggering large natural avalanches and preventing standard control operations.
Officials from Parks Canada said avalanche control work carried out on March 19 produced significant results, with artillery triggering avalanches up to size 4—large enough to destroy infrastructure and reach valley floors. The highway briefly reopened overnight from 8:00 p.m. to 3:00 a.m., but deteriorating conditions forced another closure on March 20.
In a typical storm cycle, accumulating snowfall increases avalanche danger, which can then be reduced through controlled releases using artillery. However, current conditions have deviated sharply from that pattern. Instead of snow, the region is receiving significant rainfall, allowing liquid water to penetrate deep into the snowpack. This weakens structural layers and increases the likelihood of large, unpredictable avalanches.
Parks Canada reports that natural avalanches are already reaching the edge of the highway, showing just how dangerous the current situation is in British Columbia. The shift from snow to rain has also limited mitigation options an according to Parks Canada, “artillery control is no longer effective under current conditions.” Furthermore, helicopter bombing operations are not possible, possibly delaying a safe opening of Rogers Pass, as avalanche activity is occurring naturally and at large scale. This leaves highway managers with few options beyond waiting for conditions to stabilise.
According to Parks Canada, two key factors are required before the highway can safely reopen:
- A drop in temperatures, allowing the snowpack to refreeze and strengthen
- A decrease in natural avalanche activity
Until both conditions are met, the risk to motorists remains too high.
The situation in Rogers Pass reflects broader conditions across western Canada and the U.S., where unseasonably warm temperatures and rain-on-snow events are driving a dangerous wet avalanche cycle. “Its ugly out there, heavy rain soaked snow with large destructive avalanches running full path and breaking trees,” Avalanche Canada advised. “Now is a great time to stay out of the backcountry,” the Canadian avalanche advisory center added.
Unlike dry slab avalanches, which are often predictable and controllable, wet avalanches are heavier, slower-moving, and far more difficult to manage—especially when triggered naturally.
Weather forecasters anticipate that cooler temperatures later in the day could begin to stabilise the snowpack, potentially allowing for a reopening. However, timing remains uncertain, and officials are urging travelers to monitor updates closely.
Until then, one of Canada’s most critical transportation corridors remains at the mercy of a rapidly weakening snowpack—where rain, not snow, is now the dominant force shaping avalanche risk.
