Climate change made B.C. floods at least twice as likely, study suggests

The study concludes that the likelihood of similar events in the future will only increase as global warming continues to upend normal weather patterns.

Catastrophic floods that swamped much of southern British Columbia last fall were at least twice as likely because of climate change, suggests new research from Environment Canada.

The study, now undergoing peer review, concludes that the likelihood of similar events in the future will only increase as global warming continues to upend normal weather patterns.

“We do find substantial ongoing increases in the probability of these kinds of events,” said Nathan Gillett, an atmospheric physicist and manager of the Canadian Centre for Climate Modelling and Analysis.

In November, B.C. saw three events come together to create unprecedented flooding.

A so-called “atmospheric river” brought two days of drenching rain. It fell on already-sodden soil that couldn’t absorb much more and was augmented by high temperatures that swelled bursting stream beds with snow melt.

The result was almost 15,000 people forced from their homes, major roads and bridges washed away and farms flooded in up to two metres of water. Landslides killed at least five people.

Insured losses have been estimated at $450 million; 600,000 chickens and 12,000 hogs died.

Gillett and his colleagues wanted to estimate the contribution of climate change to the disaster while it was still fresh in public memory. They turned to the science of climate attribution, which uses climate models to estimate the influence of one or more factors on weather events.