Human-induced climate change “contributed substantially” to the atmospheric river and ensuing floods that devastated B.C. Environment Canada scientists confirmed this last year in a new study, and warned Canadians to be prepared for more.
“The chance this kind of flood will happen has increased by 100 to 300 per cent due to human influence,” Xuebin Zhang, a senior research scientist with Environment and Climate Change Canada, told Canada’s National Observer.
The two-day atmospheric flood that swept across southern B.C. was a two-day event. The two-day atmospheric river that swept across southern B.C. in mid November led to the deaths or multiple evacuations of at least five people. It is the worst natural disaster in B.C.The infrastructure damage alone cost $7.5 billion, making it the most expensive natural disaster in British Columbia’s history.
Atmospheric river are long, narrow ribbons made of water vapour. They travel through the atmosphere, picking up vapour from the moist air in tropical regions and dropping it in cooler areas.
“Events like what happened in British Columbia will happen more often, and perhaps with even bigger magnitude,” said Zhang. “Engineers and also citizens will need to think about how they are going to deal with this.”
The study is a preprint, which means it has not yet been peer-reviewed, but Zhang says he doesn’t expect many modifications will have to be made before publication.
Although snowmelt contributed to the flooding, Zhang said the main cause was the two days of “intense precipitation” from the atmospheric river.
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The study revealed that while the intensity was only one-in-10 years, the precipitation over those two days was much more unusual, at approximately one-in-50 to 100 years.
It was also found that the likelihood of an equally strong or more powerful atmospheric river has increased at least 60% due to human-induced climate changes, which have also increased the chances of significant two-day rain by an estimated 50%.
Natural Resources Canada published last summer a 734-page report that informed the government’s December 2020 climate plan. The report identified “large gaps” in Canada’s climate change preparedness and highlighted the benefits of investing in adaptation to limit costs of climate change-related weather events.
Human-caused climate change “contributed substantially” to B.C.@environmentca scientists have revealed the devastating floods that occurred in #BC. #cdnpoli #BCFloods #ClimateChange
Canada must prepare for increased frequency and magnitude of extreme weather events by completing its national adaptation strategy, increasing national flooding risk mitigation, and appointing a natural disaster resilience advisor, Climate Proof Canada says.
Zhang said that unlike other studies, which can take over a year, this one was completed in just a few months.
Zhang stated that time was critical because the public wants more information on such events and whether they can have any connection to climate change.
He stated that senior management at Environment Canada favored the study to address the many questions Canadians have. Zhang believes that the data will be useful for climate change policy in Canada.
Natasha Bulowski / Local Journalism Initiative / Canada’s National Observer