Tofino, B.C., tsunami study points to hundreds dead, $1B in losses

The number one warning in Tofino, B.C., would non be a siren — it would be the strand palpitation.

Within proceedings, tsunami waves as tall as a five-storey building could move toward the same beaches that make the town famous and draw thousands of tourists each summer.

A new study on Cascadia earthquake and tsunami risk puts one of Vancouver Island's best-known coastal communities at the centre of a difficult question: How does a small town prepare for a disaster that may not happen for generations, but could overwhelm it within minutes?

The research suggests a major earthquake along the Cascadia Subduction Zone could expose much of Tofino to tsunami flooding, cause severe building damage and put hundreds of lives at risk in an extreme scenario — especially during peak tourist season, when the town's population swells far beyond the number of permanent residents.

Katsu Goda, the study's author and an associate professor of civil and environmental engineering at Western University, said the point is not to frighten people, but to make the risk visible before it becomes real.

"Tofino is right on the Pacific coast, so that's the highest tsunami risk because the distance matters," Goda said. "The majority of the campgrounds, the resort hotels, et cetera, are all situated in the low-lying area. So that raises the risk level in Tofino."

The Cascadia Subduction Zone runs offshore from northern Vancouver Island to Northern California. The last full-margin rupture occurred in 1700, generating a tsunami that devastated coastal Indigenous communities and crossed the Pacific to be recorded in Japan.

Full-margin Cascadia ruptures have occurred, on average, roughly every 500 to 560 years. But Goda's recurrence modelling suggests they do not happen on a predictable schedule. Instead, the geological record shows an irregular pattern, with some shorter clusters and some much longer gaps.

That does not mean the risk is high in any given year, but it is the kind of rare, catastrophic event coastal communities must plan for.

Goda's Tofino study models extreme Cascadia earthquake and tsunami scenarios, with magnitudes ranging from 8.7 to 9.1. It estimates roughly half of the town's buildings are exposed to tsunami inundation — meaning they are below 20 metres above sea level — and that most buildings hit by more than three metres of water would collapse or be washed away.

With Tofino's building stock valued around $2.27 billion, widespread damage from a major Cascadia event could push direct property losses past $1 billion.

In one severe modelled scenario, the study estimates hundreds of potential fatalities, with an upper-tail figure of 768. Goda cautioned that should not be read as the expected outcome, but should still be taken seriously.

"I don't want to emphasize the maximum values, but that is one possibility," he said. "From a scientific perspective, that is a reality given the physical conditions in Tofino."

The other challenge is speed. In a local Cascadia tsunami, the shaking itself is the warning. Depending on where people are, official alerts may not arrive before the first waves do.

Residents and visitors need to know in advance that strong or long-lasting shaking means they should move immediately to higher ground.

Goda said the time between the earthquake and the arrival of the first waves would depend on the rupture, but in a severe local scenario it could be "as short as 20 minutes."

Hilary O'Reilly, Tofino's emergency program co-ordinator, said recognizing the warning signs and acting quickly are key parts of the district's preparedness work.

"One of our primary focuses for both residents and visitors is to educate people on what those early warning signs might be and how to act immediately, because you may not have time with a Cascadia event to wait for official warning signs," O'Reilly said. "When it's safe to do so make your way to high ground immediately."

But O'Reilly said preparedness in a place like Tofino is not as simple as drawing escape routes on a map. On a summer weekend, roads can be packed and many visitors may not know where to go.

"I would say it is one of our more complex aspects of preparedness," she said.

O'Reilly said the district works with local tourism operators so visitors hear consistent safety messages before an emergency, whether they are on a whale watching tour or checking in at a hotel.

That concern is central to Goda's study, which found Tofino's changing population — especially during peak tourist season — could significantly affect the town's casualty risk.

"The people in Tofino are very aware and knowledgeable about the risks they have, but not necessarily the tourists," he said. "So I think the important message is that the casualty risk might be concentrated on the tourists who are not aware of the tsunami risk."

One major question is whether Tofino needs more vertical evacuation options — structures strong enough for people to climb above tsunami flooding when natural high ground is too far away.

Goda said vertical evacuation is worth considering because some people may not be able to reach high ground quickly enough.

"In order to escape to 20 metres in elevation, which is safe from the tsunami, people will need to travel relatively long distances," he said. "So in that context, the vertical evacuation structure could be a solution."

O'Reilly said the district is already studying that possibility.

Tsunami towers proposed for Tofino, B.C.

"One of our most significant challenges here is time combined with that exposure and human behaviour," she said. "We are consistently looking at new strategies, including built infrastructure, so there are feasibility studies underway."

Goda said community-level risk modelling matters because it can help local officials and residents understand where the consequences may be most severe.

"My contribution, from a scientific perspective, is to come up with reliable numbers," he said. "I hope people take those numbers as a serious warning ... So we can improve preparedness for the future."

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