 While molten rock comes closer to the surface it would most likely cause more fragmentation, triggering an explosive eruption that could produce an eruption column with an elevation of 20 km (12 mi) and may be sustained for 12 hours. A well-documented explosive eruption in the Garibaldi Belt with such force is the eruption of Mount Meager 2,350 years ago, which deposed ash as far east as Alberta. This would endanger air traffic and would have to take another route away from the eruptive zone. Every airport buried under pyroclastic fall would be out of service, including those in Vancouver, Victoria, Kamloops, Prince George and Seattle. The tephra would destroy power transmission lines, satellite dishes, computers and other equipment that operates on electricity. Therefore, telephones, radios and cell phones would be disconnected. Structures not built for holding heavy material would likely demolish under the weight of the tephra. Ash from the eruption plume would subside above the vent area to create pyroclastic flows and would travel east and west down the nearby Cheakamus and Squamish river valleys. These would likely have significant impacts on salmon in the associated rivers and would cause considerable melting of glacial ice to produce debris flows that may extend into Daisy Lake and Squamish to cause significant damage. The eruption column would then travel eastward and extract air travel throughout Canada from Alberta to Newfoundland and Labrador.
