Climate Change: Canada battered by devastating torrential rain months after rampant forest fires

Debris flow in flood waters around a home in the Yarrow neighbourhood after rainstorms caused flooding and landslides in Chilliwack, British Columbia, Canada. Picture: Jesse Winter/Reuters

Debris flow in flood waters around a home in the Yarrow neighbourhood after rainstorms caused flooding and landslides in Chilliwack, British Columbia, Canada. Picture: Jesse Winter/Reuters

Published Nov 23, 2021

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Canadian authorities rescued hundreds of people from highways in British Columbia last Monday as torrential rains pummelled areas causing mudslides and widespread flooding across parts of the province.

Rescuers were met with scenes of homes and vehicles submerged under muddy water, roads and bridges washed and thousands of drowned livestock as they assisted with mandatory evacuations.

In a press statement, officials said that “about 275 people who had been stuck on Highway 7 near the town of Agassiz, a small community east of Vancouver, since Sunday evening had been rescued.”

British Columbia’s Communications Director for Emergency Management, Jordan Turner, told The New York Times that by late Monday night, approximately 150 more people had been saved from other stretches of highway in the area and that rescue crews had whisked drivers away by helicopter and cleared debris from the road.

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Authorities of the Canadian city of Merritt, about 270 km north-east of Vancouver, urged its 7 000 residents to leave their homes on Monday, immediately after heavy rain caused the Coldwater River to burst its banks.

The city announced that barricades would be erected to prohibit access to the city. In Agassiz, Mayor Sylvia Pranger declared a state of emergency after a mudslide occurred and a flood watch warning was issued for the District of Kent, which includes Agassiz.

Yale Climate Connections explained on Wednesday that “an intense low-pressure system brought an atmospheric river of water vapour and torrential rains to southern British Columbia and northwestern Washington state on Monday, generating devastating flooding that virtually isolated the city of Vancouver from the rest of Canada. The floods came less than five months after the most extreme heat wave in global history affected the same region, fuelling destructive wildfires.”

Dylan Adamson climbs from a boat onto the porch of his home where he and his friends rode out surrounded by floodwaters in the Yarrow neighbourhood after rainstorms caused flooding and landslides in Chilliwack, British Columbia, Canada. Picture: Jesse Winter/Reuters

According to reports by the Meteorological Service of Canada, numerous records were set with some parts of British Columbia recording up to 250mm of rain in 24 hours. One of the highest amounts observed was the 294.3 millimetres of rain that pummeled the city of Hope, British Columbia.

The devastation caused by the flooding was widely attributed to the lack of vegetation which was wiped out by rampant wildfires in the same area a few months ago. These wildfires had been fuelled by a record heatwave that brought an insane temperature of 49.6 degrees Celsius to Lytton, British Columbia, the hottest temperature ever recorded in Canada.

The World Weather Attribution program conducted a rapid-response study which found that the heatwave would have been “virtually impossible without human-caused climate change.”

The National Oceanic and Atmospheric Administration explained that “an atmospheric river (AR) is a band of water vapour 400-600 km wide, much like a river in the sky, that acts like a pipe transporting huge amounts of water vapour north, out of the tropics.

When an atmospheric river moves over land, the water vapour transported can condense in the form of rain or snow, often causing extreme rainfall and flooding.”

The Climate Signals, an organisation connecting real-time extreme weather events to climate change further explained that “as the climate warms, ARs are expected to form in more rapid succession and grow more intense as they become wetter, longer, and wider. There is some indication that this is already happening in association with observed Pacific Ocean warming.”

“A July 2015 study found that climate change may increase horizontal water vapour transport by up to 40 percent in the North Pacific, due mainly to increases in air moisture.” The Inter-Governmental Panel on Climate Change report concurs with these findings predicting a general increase in both surface and land temperatures.

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