Heavy rains and high winds that hit British Columbia, a Canadian province known for its mountains, coastline and majestic forests, forced 17,000 people to flee their homes last week, devastating entire cities and flooding farms.
Vancouver, Canada’s third-largest city, has lost road and rail links to the rest of the country due to eroded bridges and landslides.
It was the second time in six months that the province has experienced a severe weather-related emergency, and experts say the two disasters are likely to be related to climate change.
British Columbia has been under siege this year due to record heat waves, wildfires and floods. The natural disasters have killed hundreds of people, including three in recent rains, and caused hundreds of millions of dollars in damage. The impact swept across Canada after sweeping across the province and port of Vancouver, which is vital to the country’s economy.
“In the past six months, British Columbia has burned and drowned,” said Murran Smith, executive director of Clean Energy Canada, the climate program at Simon Fraser University in Vancouver. “So there is no stronger evidence of climate change right now than here in British Columbia.”
In July, record temperatures hitting 121 degrees Fahrenheit led to drought and uncontrolled wildfires. The heat, which was concentrated in the interior of the province, killed 595 people from June to August, and the entire city was engulfed in fire.
Last week’s floods saved more lives, but destroyed vital infrastructure and left cargo piling up at the Port of Vancouver, Canada’s gateway to Asia. The country’s supply lines have also been disrupted at a time when American ports are too protected to offer much assistance.
Experts said that events in this sequence – heat, fire, drought, flood – can cause so-called complex effects.
Drought can dry out vegetation, which in turn feeds and intensifies fires. The fire itself can weaken or kill plants and make the soil less permeable, which means rain is more likely to drain off rather than soak up, causing flash floods and landslides.
Rachel White, a professor at the University of British Columbia who studies the effects of large-scale atmospheric events on extreme weather conditions, said it was impossible to say with certainty whether the extraordinary heat waves and devastating rains were a direct result of climate change.
“We need to do more research to really try to understand what’s going on here,” she said. “Is this also a sign of climate change or is British Columbia just incredibly unlucky this year?”
However, one thing is for sure, she said: “These events have been exacerbated by climate change.”
A common weather event known as the “atmospheric river” has resulted in devastating flooding in the province and has set rainfall records in several communities. The moisture conveyor belt, perhaps better known as the “Pineapple Express,” is a relatively narrow but very long strip of rapidly moving moist air that forms in the Pacific Ocean near Hawaii.
Typically, such systems release this moisture in the form of heavy rain when they reach the coastal mountains of British Columbia, and dry out before they enter the dry inland region on the other side. “But this atmospheric river was different,” said Armel Castellan, a meteorologist with the Environment and Climate Change Canada Weather Service.
“There was so much strength in him that he was able to climb these mountains and really descend into what is otherwise a dry belt,” he said.
Alex Hall, professor of atmospheric sciences at the University of California, Los Angeles, added that the phenomenon is remarkable for its scale. For example, the inner city of Hope received 11.6 inches of rain in 52 hours, about a third more than the amount of rain that typically falls throughout November.
“What is abnormal is such large atmospheric river phenomena,” he said, adding that in terms of rainfall, these phenomena “are almost in line with historical records.”
Mr Castellane said that since the hinterland already had a wet dip already, the land was saturated before the storm hit. The situation was aggravated by the fact that at high altitudes there was relatively little snow to absorb the water. In addition, due to extreme heat, drought and wildfires, little vegetation is left to slow down or prevent landslides.
“When you tune these sequences correctly, you create even more extreme conditions,” said Dr. Hall.
Human interference with geography also made things worse. Much of the fertile farmland near Abbotsford was created 100 years ago as a result of the draining of Lake Suma, a process that forced the indigenous population to move to other lands. While pumps and dams were holding back some of the water, a storm last week allowed the lake to regain its condition a century later.
As it rained and the roads closed, panicked shoppers recalled the early days of the pandemic and cleared out several grocery stores, especially in the Vancouver area.
Rebuilding lost bridges, roads and railways could take months. But Greg Wilson, director of British Columbia government relations with the Retail Council of Canada, said widespread shortages in the province were unlikely. Fresh produce can still be shipped by highway from Seattle, which typically carries most of the supply to Vancouver at this time of year.
One highway from Vancouver reopened to cars and trucks over the weekend, while another restored a single lane for important travel. But trucks from elsewhere in Canada mostly make their way to Vancouver, bypassing the United States. And much of the interior of British Columbia, the hardest hit area, is still open to the rest of Canada by train and truck.
“There is no danger of food running out in the Vancouver area,” said Mr. Wilson. “There will be problems, but there are many proposals.”
British Columbia has been a leader in efforts to mitigate the effects of climate change, said Barry Prentice, a professor at the University of Manitoba and former director of its Transportation Institute. In 2008, he introduced North America’s first carbon tax. He also took physical measures. The port in Vancouver has been raised about three feet to accommodate rising sea levels, he said.
But the province’s mountainous nature, he said, limits opportunities and makes the recovery process difficult and time-consuming.
“It’s very difficult to try to make everything sustainable,” he said. “We don’t have many options for routes through the mountains.”
Opening delays are likely to have a significant impact across Canada, as the port of Vancouver connects the country to Asia for both imported consumer goods and economically vital exports of inputs such as grain and potash for fertilizers. Although the rail link to Prince Rupert Port in northern British Columbia remains open to the east, Professor Prentice said the port cannot physically handle all Vancouver traffic beyond normal operations.
While the transport network may be strengthened during the recovery, Professor Prentice said the only long-term solution remains to effectively tackle climate change.
Ms Smith of Clean Energy Canada said Prime Minister Justin Trudeau’s government has a credible and ambitious climate plan, but that the country has yet to rein in its oil and gas industry, especially oil sands operations based largely in neighboring Alberta.
“We need to reduce emissions from the oil and gas sector; this is one of Canada’s biggest problems, ”she said. “All these other good strategies, we need to see how they are implemented without delay. Inaction is often disguised as flexibility, and that time has passed. “
Although water has begun to recede in most of the floodplains, it is unclear when the evacuees will return home or the abandoned vehicles will be returned to their owners. And even more dangers may lie ahead for British Columbia. Forecasts predict another series of heavy rainfalls this week.
Winston Choy-Shagrin made reporting.