After a hot summer and uncontrolled wildfires, British Columbia suffered record rainfall, which forced the evacuation of towns and destroyed highways and railway lines.

Flooding occurred in the Sumas Prairie area in Abbotsford, British Columbia last week. Image credit: Don Mackinnon/Agence France-Presse — Getty Images

Authors: Ian Austin and Vjosa Isai

Last week, heavy rains and strong winds fell in British Columbia, Canada, which is famous for its mountains, coastlines and majestic forests, forcing 17,000 people to leave their homes, leaving the town empty and flooding farms.

Vancouver, Canada’s third largest city, lost road and rail connections to the rest of the country, and was severed by washed-out bridges and landslides.

This is the second major weather-related emergency in the province in six months. Experts said the two disasters may be related to climate change.

British Columbia was surrounded by record high temperatures, wildfires and floods this year. The disaster has killed hundreds of people-including three from the recent rains-and caused hundreds of millions of dollars in damage. After putting the province and the Port of Vancouver into trouble, the impact spread across Canada, and the Port of Vancouver is vital to the country's economy.

Melan Smith, executive director of the Canadian Clean Energy Program of the Simon Fraser University Climate Program in Vancouver, said: "In the past six months, British Columbia has been burned and drowned." "So there is nothing better than British Columbia. It's more proof of climate change."

In July, record temperatures as high as 121 degrees Fahrenheit brought droughts and uncontrollable wildfires. From June to August, high temperatures concentrated in the inland areas of the province, killing 595 people and burning entire towns.

Last week’s floods saved more lives, but destroyed important infrastructure and caused cargo to pile up at the port of Vancouver, Canada’s gateway to Asia. When the reserve force of the US ports was too strong to provide much help, the country's supply lines were also disrupted.

Experts say that events that occur in this order—high temperature, fire, drought, and flood—may have a so-called compound effect.

Drought will dry out vegetation, which in turn will encourage and exacerbate fires. The fire itself weakens or kills plants and reduces the permeability of the soil, which means that rainwater is more likely to run off rather than infiltrate, leading to flash floods and landslides.

Professor Rachel White of the University of British Columbia studies how large-scale atmospheric patterns can lead to extreme weather. She said it is impossible to determine whether abnormally high temperatures and devastating rainfall are directly caused by 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's luck this year very bad?"

However, she said, one thing is certain: "These events are getting worse due to climate change."

A common weather event called "atmospheric river" caused devastating floods in the province and set rainfall records in multiple communities. The moisture conveyor belt, perhaps better known as the Pineapple Express, is a relatively narrow but long belt of fast-moving, humid air formed in the Pacific Ocean near Hawaii.

Normally, once this system reaches the coastal mountains of British Columbia, it releases water in the form of heavy rainfall and gradually disappears before entering the dry inland area on the other side. But this atmospheric river is different, says Amer Castellan, a meteorologist with the Canadian Meteorological Agency for Environment and Climate Change.

"It has such a powerful effect that it can ride on those peaks and truly release into the originally dry terrain," he said.

Alex Hall, professor of atmospheric sciences at the University of California, Los Angeles, adds that this phenomenon is known for its scale. For example, the inland town of Hope experienced 11.6 inches of rain in 52 hours, one third more than the usual annual rainfall in November.

"It is not normal for such a large atmospheric river event to occur," he said, adding that in terms of rainfall, these events are "almost on par with historical records."

Mr. Castellan said that since the inland areas have already experienced usually humid rainfall, the ground was saturated before the storm hit. To make matters worse, there is almost no snow at high altitudes that can absorb water. In addition, the summer heat, drought and wildfires rages, and there is almost no vegetation to slow down or prevent mudslides.

"When you set up these sequences correctly, you will have more extreme conditions," Dr. Hall said.

Human intervention in geography has also made things worse. Most of the fertile farmland near Abbotsford was formed by draining Lake Sumas 100 years ago, a process that forced the aborigines to migrate to other lands. Although pumps and dams blocked some water, last week's storm restored the lake's vitality after a century.

With heavy rains and road closures, panicked shoppers relived the early scenes of the pandemic and cleared several grocery stores, especially in the Vancouver area.

It can take months to rebuild lost bridges, roads and railways. But Greg Wilson, director of government relations for the Canadian Retail Commission in British Columbia, said the province is unlikely to experience widespread shortages. Fresh produce can still be reached via the highway from Seattle, and at this time of the year, most goods usually follow this route to supply Vancouver.

An expressway outside Vancouver was reopened at the weekend to allow light cars and trucks to pass, and the other expressway restored a single-lane lane for basic travel. But trucks from other parts of Canada mostly bypass the United States to reach Vancouver. Most of the inland areas of British Columbia, the hardest-hit province, are still open to the rest of Canada by train and truck.

"There is no danger of running out of food in the Vancouver area," Mr Wilson said. "There will be challenges, but there is a lot of supply."

Barry Prentice, a professor at the University of Manitoba and former director of the Institute of Transportation, said that British Columbia has been a leader in efforts to mitigate the effects of climate change. In 2008, it introduced the first carbon tax in North America. It also took physical measures. He said the port of Vancouver has been raised about three feet to accommodate rising sea levels.

But he said that the mountainous nature of the province limits all possibilities and makes the reconstruction process difficult and lengthy.

"Trying to make everything flexible is very difficult," he said. "For the route through the mountains, we don't have many choices."

The delay in reopening is likely to have a significant impact on Canada as a whole, because the port of Vancouver connects the country with Asia, whether it is importing consumer goods or exporting grains and potash and other important resources for fertilizers. Although the rail line to the Port of Prince Rupert in northern British Columbia is still open to the east, Professor Prentice said that apart from normal operations, the port cannot actually handle all traffic in Vancouver.

Although it is possible to strengthen the transportation network during the reconstruction period, Professor Prentice said that the only long-term solution is still an effective response to climate change.

Ms. Smith of Canada’s Clean Energy stated that Prime Minister Justin Trudeau’s government has a credible and ambitious climate plan, but the country has not yet controlled its oil and gas industry, especially in neighboring Alberta.​​ Oil sands business.

"We need to reduce emissions from the oil and gas sector; this is one of Canada's biggest challenges," she said. "All these other good policies, we need to see them implemented immediately. Many inactions are disguised as flexibility, and we have passed that era."

Although the water in most flooded areas has begun to recede, it is not clear when the evacuees will return to their homes or when the abandoned cars will be returned to the owners. British Columbia may face more dangers. The forecast predicts that there will be another heavy rain this week.