British Columbia

Indigenous knowledge the cornerstone of new tsunami modelling for Vancouver Island's northwest coast

The Strathcona Regional District partnered with First Nations to better understand the the potential impacts of tsunamis on local communities and have now released new maps and modelling information.

Oral history of tsunamis from First Nations complements computer modelling

Many areas along B.C.'s coast are prone to tsunamis, as illustrated by this sign in Prince Rupert. The Strathcona Regional District is partnering with the Nuchatlaht and Kyuquot Checlesaht First Nations to create a high-resolution tsunami-modelling system for northwest Vancouver Island from Gold River to Cape Scott. (Andrew Kurjata/CBC)

The results of a collaborative project mapping out tsunami risk between the Strathcona Regional District and the Nuchatlaht and Kyuquot Checlesaht First Nations on Vancouver Island have been released.

High-resolution data modelling for the area between Gold River and Cape Scott is now available for the public online

This area is particularly vulnerable to tsunamis, from either an earthquake triggered in the Cascadia subduction zone to the west, or one from the Alaska-Aleutian subduction zone to the north. 

Shaun Koopman, the protective services co-ordinator for the Strathcona Regional District, says the project is crucial given the life and death risk.

"There is no wave more powerful than the ocean … six inches will move a vehicle. So it is so important that someone knows where that safety boundary is, whether the wave is coming from Cascadia or Alaska," Koopman said on CBC's All Points West.  

The mapping project, which began last year with $450,000 in funding from an emergency preparedness grant from the provincial government, used both Indigenous knowledge and oral history as well as computer modelling. 

Phillippe St-Germain, a project manager with Northwest Hydraulic Consultants and coastal engineer on the project, said these historical accounts were essential. The accounts and results of the tsunami modelling were obtained in close collaboration with Ocean Networks Canada.

"A piece of [the project] was to collect Indigenous knowledge about stories about people who lived through the 1964 tsunami from Alaska but also stories that go as far back to the 1700 tsunami that was generated at the Cascadia subduction zone, which is just a few hundred kilometres off the west coast of Vancouver Island," St-Germain said. 

"Collecting that information substantiated the results that our computer models were predicting." 

Waves crash against rugged rocks along the Wild Pacific Trail in Ucluelet, B.C. on Jan. 19, 2018. (Melissa Renwick/Canadian Press)

The team was also able to determine an estimate of the arrival time of the tsunami waves after an earthquake occurs. 

"On the open coast, we're looking at the arrival of the wave within 15, 20 minutes after the initiation of the earthquake," said St-Germain. 

The further inland, the longer it takes for the wave to arrive — up to 40 minutes in some areas. 

"Time is of the essence and that can make a big difference to allow people to get to a safe place," he said. "Those extra minutes are precious," St-Germain said.

The next steps in the project include figuring out ways to communicate this modelling data to the general public, Koopman says. This includes working with First Nations to translate into different languages, different immigrant groups, literacy groups and tourist associations to make sure it is shared widely and broadly. 

"We [want] to ensure that everybody is getting this crucial life saving information," Koopman said. 

With files from All Points West