An SFU professor claims that a series of devastating landslides that struck the town of Oso, WA on March 22, causing numerous fatalities and severe damage to the area, could occur here in BC.
Residents who were in the area at the time sustained varying degrees of injuries and many were rescued from the debris. Nevertheless, as of April 3, 30 people are confirmed dead, with 22 still missing, as reported by CNN and BBC.
SFU earth science professor John Clague believes that a similar event could hit even closer to home. As a region that shares many physical traits with the neighbouring state to the south, BC is also at risk of undergoing a similar ordeal.
Despite the suddenness of the actual event in Oso, the disaster was not a complete surprise. The National Weather Service issued a warning in the Seattle area on March 4, nearly two weeks prior. “Cumulative rainfall over the last week has soaked soils to the point where the Washington landslide risk is at elevated levels,” explained forecasters to the Seattle P-I.
The Oso area has a history of landslides. As Clague noted, the area is filled with many beautiful flat surfaces and valleys that attract residents and visitors alike; however, the location also contains many bluffs with loose sediment that could potentially dislodge under heavy rain conditions.
“Landslide” is an umbrella term for different slope movements — sliding, creeping, slumping, toppling, and falling. Though landslides can occur due to various reasons, heavy rainfall is a major culprit. The landslide that hit Oso was a mudflow. As Clague explained, “The bluff that failed [in Oso] is not rock, it’s loose materials — essentially silt, sand, clay, and any kind of water saturated loose materials — that are inherently unstable.”
In a report with Global News, Clague stated that, “We [the residents of British Columbia] have to be aware that we do live in a country with this wet unstable topography where we are going to get landslides.” He continued, pointing out Chilliwack Valley as a potential location where a landslide event might occur due to its topographical similarities to Oso.
Landslides are hard to prepare for and harder still to react to, given the short time frame in which they occur. One definite sign that the ground is on the verge of breaking loose is ground stress. If someone happens upon an area, even a few days before an impending landslide, they will hear cracking from the ground, Clague explained. In some cases, there may be slippage and possibly chunks of sediment dislodging or breaking free.
In any case, if there is any sign of a landslide, the best course of action is to run away. If the landslide is heading downward, the best direction to run is uphill, towards higher ground, or to the opposite side of the valley or highway, advised Clague.
While there is no definite cause for concern at the moment, Clague warned that we should nonetheless be aware of the potential hazards in the place we call home.
