Report into destructive 2023 Okanagan wildfires details how fire spread

A new report on the destructive and costly 2023 Central Okanagan wildfires is detailing how flames spread in communities and why some homes were more likely to catch fire while others were spared.

The report, titled A wildland-urban post-fire case study: The Grouse Complex, focuses on measures residents can take to reduce the likelihood of their homes catching fire — measures promoted by FireSmart.

The Grouse Complex wildfires began in August 2023 after a period of drought. They included the McDougall Creek, Walroy Lake and Clarke Creek wildfires in the Okanagan Lake area. Together, they burned 15,076 hectares, the report says, led to more than 30,000 people having to flee their homes and damaged or destroyed 303 structures.

The fires affected West Kelowna, Westbank First Nation, Kelowna and the District of Lake Country. According to the report, insured losses approached half a billion dollars, making it one of the most catastrophic wildland-urban fires the region has ever experienced.

The report details how the fires entered communities almost entirely by airborne burning embers, not direct flames. Once in neighbourhoods, the embers multiplied, they spread through yards and some closely spaced homes caught fire via structure-to-structure ignition.

"The fire was ferocious. It swept through our community due to unusual weather that had been building for months. It really was a true firestorm," said West Kelowna fire Chief Jason Brolund. "Our community was devastated."

Brolund said he was excited to learn that researchers were carrying out the study in his community and welcomed the report, which he said simply confirmed what he saw on the ground and what the group FireSmart, which was involved in the report, had been promoting.

"During that firestorm, embers blew through the air like snow, and I remember seeing that and being stuck in the middle of it in those first few nights."

The report assessed 21 damaged homes and 17 that weren't damaged. It found the ones that were damaged mainly featured coniferous trees like cedars and junipers within 10 metres of the structure, were located on steep slopes, had combustible siding and decks and plenty of easily ignitable material quite close to the home, like firewood, lumber and vehicles.

The homes that weren't damaged lacked those characteristics.

The report describes a common process by which homes burned — flying embers ignited vegetation and other material within 10 metres of the structure, and plumes of hot gases, flames and embers ignited parts of the structure like siding and eaves, before the fire got into the attic and spread through the house.

"We did drive through the neighbourhoods and we did see clear examples of homes that were lost that likely we would have had a better chance at saving had there been different choices made around landscaping materials and construction materials," Brolund said.

He said the challenge for his community will be living with wildfire in the years ahead. 

"I know we will face another fire in our community and our region. My hope is it won't be as devastating as the previous ones."

Brolund said his fire department has been promoting FireSmart recommendations to reduce the risks, but that the municipality will also look into regulating certain steps as wildfires increase in regularity and severity. The community's wildfire resiliency plan will be brought to mayor and council for their consideration in the coming weeks.