The snow war
Rogers Pass, an important link for the Trans-Canada Highway and Canadian Pacific Railway, sits in one of the world's most active avalanche areas. The pass is flanked by steep mountains and receives an average of 10 meters of snow at the treeline each winter, creating ideal conditions for snow slides. This 40-kilometer stretch of highway is threatened by 134 distinct avalanche paths. The history of the pass is marked by tragedy; between 1885 and 1916, over 250 railway workers died in avalanches. The deadliest single event in Canadian history occurred here on March 4, 1910, when an avalanche killed 58 men who were clearing a previous slide from the tracks.
To keep this important economic corridor open, Parks Canada and the Canadian Armed Forces collaborate on Operation PALACI, the longest-running domestic military operation in Canadian history. This program uses military artillery to proactively trigger smaller, controlled avalanches before the snowpack can build to catastrophic levels. From 17 roadside gun positions, gunners from the Royal Canadian Artillery fire 105mm C3 howitzers at 270 pre-determined targets on the mountainsides. These targets can be up to five kilometers away. The explosive shells create a shockwave that fractures weak layers in the snowpack, releasing predictable slides. In a typical season, gunners fire hundreds of rounds, but have fired over 1,000 in a busy winter.
An engineered defense
The Rogers Pass corridor relies on a sophisticated system of static defenses and advanced forecasting. The most visible structures are the snow sheds—massive concrete tunnels that allow avalanches to pass harmlessly over the highway. In addition to the sheds, a network of earthen dams, dikes, and mounds is built into avalanche paths to stop, slow, or redirect moving snow.
The entire operation is guided by a team of avalanche forecasters. They collect data from remote weather stations high in the mountains and conduct hands-on analysis by skiing into high-elevation areas and digging snow pits up to five meters deep. This allows them to examine the distinct layers of the snowpack to identify instabilities. This data feeds into forecasting models that determine when and where control missions are necessary. The system is augmented by the world's largest Avalanche Detection Network, which uses infrasound detectors and long-range radar to monitor avalanche activity 24/7, providing real-time data and confirmation of artillery effectiveness. This combination of military force, heavy engineering, and detailed science keeps the important transportation artery open through the treacherous Selkirk Mountains.