Low population density in British Columbia, with populations clustering along the southern border, and strong geomorphic north-south obstructions conspire to limit transportation and communication corridors. The corridors are often multi-purpose with rail, roads, telecommunications, and pipelines in close proximity, and extremely vulnerable to hazards. Classic examples are Highway 99 (the Sea-to-Sky corridor) between Vancouver and Whistler, and Highway 1 (the Fraser Canyon) between Hope and Ashcroft:
Highway 99: The Sea-to-Sky corridor
Highway 99 has repeatedly been shut down due to rockfall (1969 Porteau, 1996 Highway 99, and 1971 Furry Creek) or debris flows (1981 M-Creek Bridge, and 1983 Alberta Creek), with even more events that would have destroyed the highway had it been built when they occurred (1955 Rubble Creek, 1915 Jane Camp, and 1921 Britannia Beach). The alternate route involves a six-hour detour along unpaved logging roads.
Highway 1: The Trans-Canada highway in the Fraser Canyon
The Trans-Canada highway, Highway 1, is equally at risk. While the 1905 Spences Bridge event took out only a small piece of an earlier road, the construction of rail lines through the corridor led to the 1914 Hell’s Gate rockfall blocking a vital salmon migration path. Only dangerous clearing, and construction of the fish ladders to allow spawning despite the even-narrower canyon, have prevented the collapse of the salmon fishery. Rockfall frequently disrupts the rail lines (1971 Fraser Canyon, 1997 Boston Bar), requiring that CPR and CN expend considerable energy on netting small rocks, automated alerts for broken track, and manually inspecting rails for damage or suspension through special patrols. The alternate route is Highway 3, passing over the deposit of the 1965 Hope Slide (and a prehistoric event), the largest-volume historic landslide in the province, and through the notoriously avalanche-prone Coquihalla Pass.
Highway 3: The Coquihalla Pass
The Coquihalla Pass experiences an average of 100 avalanches a year southeast of the summit, although avalanche shelters, firing artillery to trigger small avalanches before the snowpack gets too deep, and closing the road during extreme weather, are among efforts to mitigate the risk. With improvements to avalanche prevention and mitigation techniques along major transportation corridors, industrial deaths have decreased. Unfortunately, increase in backcountry use for recreational purposes has increased the number of avalanche deaths for even trained users.