Mount Price (British Columbia) - Volcanic Hazards - Effects

Effects

Mount Price is near the highly populated southwest corner of British Columbia, indicating that it poses a serious threat to the surrounding area. Even though Plinian eruptions have not been identified at Mount Price, Peléan eruptions can also produce large amounts of volcanic ash that could significantly affect the nearby communities of Whistler and Squamish. Mount Price is also situated in the immediate proximity of a major air traffic route. Volcanic ash reduces visibility and can cause jet engine failure, as well as damage to other aircraft systems. Peléan eruptions may cause short and long term water supply problems for the city of Vancouver and most of the Lower Mainland. The catchment area for the Greater Vancouver watershed is downwind from Mount Price. An eruption producing floods and lahars could destroy parts of the Sea to Sky Highway, threaten communities such as Brackendale and endanger water supplies from Pitt Lake. Fisheries on the Pitt River would also be at risk. These volcanic hazards become more serious as the Lower Mainland grows in population. More than 60% of British Columbia's people live in the Lower Mainland and it is one of Canada's most rapidly changing ecoregions. This is mostly because of its increasing population and economic development.

Because andesite is the main type of lava erupted from Mount Price, lava flows are a low to moderate hazard. Andesite lava is intermediate in silica content, indicating that it has a higher viscosity than basaltic lava, but less viscous than dacite and rhyolite lava. As a result, andesite lava flows typically move slower than basaltic lava flows and are less likely to travel far from their source. Dacite and rhyolite lavas are usually too viscous to flow far from a volcanic vent, resulting in the formation of lava domes. An exception of this is the 15 km (9.3 mi) long Ring Creek dacite lava flow from Opal Cone on the southeastern flank of Mount Garibaldi, a length that is normally attained by basaltic lava flows.

Concerns about The Barrier's instability due to volcanic, tectonic or heavy rainfall activity prompted the provincial government to declare the area immediately below it unsafe for human habitation in 1980. This led to the evacuation of the small resort village of Garibaldi nearby and the relocation of residents to new recreational subdivisions away from the hazard zone. Should the northwest lava flow completely collapse, Garibaldi Lake would be entirely released and downstream damage in the Cheakamus and Squamish rivers would be considerable, including major damage to the town of Squamish and possibly an impact-wave on the waters of Howe Sound that would reach Vancouver Island. The landslide area is referred to as the Barrier Civil Defence Zone. Although landslides are unlikely to happen in the near future, signs are posted at the zone to make visitors aware of the potential danger and to minimize the chance of fatalities in the event of a slide. For safety reasons, BC Parks recommends visitors not to camp, stop or linger in the Barrier Civil Defence Zone.