A seismic event in Tofino, British Columbia, wouldn’t be signaled by sirens, but by ground tremors. Tsunami waves, potentially towering five stories high, could swiftly approach the town’s renowned beaches, frequented by numerous summer tourists.
A recent study on the risk of a Cascadia earthquake and tsunami highlights the unique challenge facing Tofino, a well-known coastal community on Vancouver Island. The study poses the question of how a small town can ready itself for a disaster that may occur generations from now but could swiftly overwhelm it.
The research indicates that a significant earthquake along the Cascadia Subduction Zone could expose a large part of Tofino to tsunami flooding, leading to extensive building damage and endangering hundreds of lives, particularly during peak tourist seasons when the town’s population surges beyond its permanent residents.
Katsu Goda, the study’s author and an earth sciences associate professor at Western University, emphasized that the goal is not to instill fear but to highlight the visible risk before it materializes. Tofino’s geographical location on the Pacific coast places it at high tsunami risk due to proximity, with many key facilities like campgrounds and hotels situated in low-lying areas, elevating the town’s vulnerability.
The Cascadia Subduction Zone stretches from northern Vancouver Island to Northern California, with the last major rupture occurring in 1700, causing a devastating tsunami that affected coastal Indigenous communities and even reached Japan. While historical data suggests full-margin Cascadia ruptures occur every 500 to 560 years on average, the irregular pattern makes predicting such events challenging.
Although the immediate risk may not be high, coastal communities must still prepare for potential rare, catastrophic events like a Cascadia earthquake and tsunami. Goda’s study envisions extreme scenarios with earthquake magnitudes ranging from 8.7 to 9.1, estimating that about half of Tofino’s buildings are at risk of tsunami inundation, potentially leading to significant structural damage and collapse if exposed to over three meters of water.
With Tofino’s building assets valued at $2.27 billion, the study warns that a major Cascadia event could result in property losses exceeding $1 billion. In a severe hypothetical scenario, it projects several hundred fatalities, emphasizing that while not the expected outcome, such risks should be taken seriously.
The critical issue is the time sensitivity in responding to a local Cascadia tsunami, where the seismic shaking itself serves as the primary warning. Depending on the earthquake’s nature, official alerts might not precede the initial waves, necessitating swift action from residents and visitors to move to higher ground upon sensing strong or prolonged shaking.
Tofino’s emergency program coordinator, Hilary O’Reilly, emphasized the importance of recognizing warning signs and acting promptly, especially given the limited timeframe between an earthquake and potential tsunami arrival. Educating both residents and tourists on immediate evacuation protocols is crucial, as highlighted by the town’s preparedness efforts.
Preparedness in Tofino involves complex challenges, such as managing crowded roads during peak tourist periods, where visitors might be unfamiliar with evacuation routes. Collaboration with local tourism operators to disseminate consistent safety messages is vital, given the significant impact of changing population dynamics, particularly during peak tourist seasons, on the town’s overall risk.
The study also explores the need for vertical evacuation options in Tofino, structures designed to provide refuge above tsunami flooding when natural high ground is inaccessible. Considering that reaching safe elevations might require traversing long distances, vertical evacuation structures could offer a viable solution in enhancing evacuation capabilities.
Community-level risk modeling is crucial for local officials and residents to identify high-consequence areas and improve preparedness measures. By providing reliable data, the study aims to raise awareness and prompt proactive steps to enhance Tofino’s resilience against potential Cascadia earthquake and tsunami events.