Heavy rains aren’t unusual in the North Vancouver community of Deep Cove, but when Ashifa Saferali saw an electric bike floating in the middle of the street, she knew this storm was something different.

Saferali is the owner of Honey Donuts and Goodies, a staple in the community where she has lived and worked for nearly three decades.

The region has experienced flash floods before, but nothing like the torrent of October 19, the day of the provincial election in British Columbia.

“There’s a creek near our house and I don’t know if that creek was filled with leaves or debris, but it was going down really fast, and within an hour the flow of water was just gushing down. hill and go straight down,” Saferali said, “It was pretty crazy.

By the end, 350 millimeters of rain had fallen on North Vancouver, turning streets into rivers that flowed through waterfront homes, piling up rocks and gravel and triggering a local state of emergency. The district informed residents of six homes along the waterfront that they should evacuate.

The flood is an example of how municipal infrastructure is struggling to meet the demands of a rapidly changing climate, as the frequency and severity of extreme events worsens.

Engineers who once looked to history to plan protective measures must instead look to the future, said Shahria Alam, a civil engineering professor at the University of British Columbia’s Okanagan campus.

He gave the example of municipal engineers designing a stormwater drainage system, who might study rainfall going back 50 years.

But weather conditions change quickly.

“Which means the system you designed won’t be able to absorb that much extra water, and then, of course, your system will fail and disaster will strike,” Alam said.

“Unfortunately, these types of incidents will continue to occur due to climate change. »

Some communities are aware of the challenges and are preparing for them.

The City of Vancouver says in its climate change adaptation strategy that by the 2050s, average fall precipitation is expected to increase by 12 percent.

But what is more worrying from an infrastructure perspective is the increasing prevalence and severity of “extreme precipitation events.” It says precipitation so heavy that it would have occurred only once every 20 years, from 1981 to 2010, will occur twice as often by the 2050s.

The average amount falling in a single day during such an event will increase by 20 percent to 86 millimeters, it says.

The city says it will prepare by studying steep slopes that are likely to be unstable and managing rainwater to better allow it to be filtered and stored.

But even cities that have diligently improved their infrastructure over the years can find their drainage systems outdated.

District of North Vancouver Mayor Mike Little said the city has spent millions to improve infrastructure, including the Gallant Creek watershed system in Deep Cove, which has seen many heavy rains over the past ten years. recent years.

But the October 19 storm was so intense that it crippled the system by clogging it with enormous amounts of debris.

Little remembers seeing city crews using a backhoe that day as they attempted to clear the steep Gallant Avenue catch basin, removing “six to eight feet long woody debris.”

“Even though it had been cleared ahead of time, there was so much stuff falling down that it was still locked,” said Little, whose own basement flooded.

Honey Donuts is located on Gallant Avenue.

“You couldn’t even walk. If you crossed, the water would be up to your knees,” said owner Saferali.

Across the street, Deep Cove Collective gift shop manager Heather Radant said she was left soaking wet as she struggled in vain to keep the rising waters out, barricading the store with plywood, sandwich boards and sandbags provided by city staff and neighbors.

She said the scene of the store being flooded was “wild”.

“I was like, ‘Man, how can I stay here and keep trying to keep the sewers clean?’ How long will the water continue to flow? I didn’t even know that,” Radant said.

Alam said the ideal long-term answer does not lie in more concrete infrastructure.

Instead, he talked about “climate-resilient” solutions, such as harvesting rainwater and installing “green roofs” on buildings, covered with plants and soil, to accumulate and retain moisture.

A new stormwater treatment technology, known as continuous deflective separation, could better filter debris and sediment from runoff, Alam said.

But the solutions can be costly.

“I have seen in many places that they are working hard and making improvements. But not every city has these kinds of resources and many cities are struggling to keep up,” Alam said.

Back in Deep Cove, Honey Donuts is bustling again, with a line out the door on a recent afternoon.

Across the street, Deep Cove Collective had reopened, thanks in part to customers and neighbors who dropped off dehumidifiers and fans to dry the store.

“And that’s one thing I love about this community: everyone comes together and helps everyone,” Saferali said.