Nearly half of landslides during B.C. weather disaster linked to logging, wildfire: study

Brenna Owen · The Canadian Press

· Posted: Mar 21, 2025 2:24 PM EDT | Last Updated: 3 minutes ago

A survey has recovered astir fractional of the landslides, debris flows and washouts that occurred during British Columbia's atmospheric stream catastrophe successful November 2021 originated successful areas that had been logged oregon burned by wildfire.

Severe rains triggered a landslide that killed 5 radical connected a agelong of Highway 99 eastbound of Pemberton, portion ample swaths of roads and bridges were washed away, cutting disconnected coastal B.C. from the remainder of the country.

Another 18,000 radical were forced to evacuate their homes successful southwestern B.C. arsenic the bid of drenching storms parked implicit the country for days, flooding farms and homes successful the Fraser Valley.

The study, published successful the peer-reviewed diary Earth Surface Processes and Landforms, covered astir 70,000 quadrate kilometres successful the region, examining 1,360 debris flows, landslides and slope erosion triggered by the upwind event.

It recovered 17 per cent of those hazards originated wrong burned areas, 14 per cent occurred astatine oregon beneath roads utilized by assets industries, and an further 15 per cent stemmed from logging chopped blocks, for a full of 46 per cent.

University of British Columbia (Okanagan campus) engineering professor Dwayne Tannant said helium was not amazed that the survey recovered geohazards are much apt to beryllium triggered successful terrain that has been disturbed.

"If you beryllium connected a level and look retired the model [in B.C.], you spot the interaction of our logging practices due to the fact that the wide cuts amusement up precise clearly," helium said successful an interview.

WATCH | New survey links 2021 floods to logging, wildfires:

The survey says the state has improved logging practices implicit the past respective decades, but "the astir 400 assets roadworthy and cutblock-related geohazards triggered by the November 2021 (storm) amusement that these issues persist."

The insubstantial says astir 4,000 quadrate kilometres of wood successful the survey country had been logged since 1990, with 3,600 quadrate kilometres logged betwixt 1900 and 1990.

Representatives of B.C.'s Forest Ministry and Transportation Ministry did not instantly respond to a petition for remark connected the study's findings.

Increase successful geohazards 'likely'

The insubstantial was published successful January and written by Carie-Ann Hancock, a nonrecreational geoscientist with the consulting steadfast BGC Engineering.

The survey besides looked astatine much than 35,000 kilometres of wood work roads.

WATCH | City faces suit aft 2021 floods:

"Nearly fractional of the resource-road failures were from unmapped and presumably unmaintained assets roads," the insubstantial says. "If these geohazards are to beryllium efficaciously managed to trim downstream impacts, important effort would beryllium required to representation their locations and measure their existent stability."

More than 1,600 wildfires had besides scorched 8,700 quadrate kilometres of onshore successful 2021, making it B.C.'s third-worse play connected grounds astatine the time, the insubstantial says.

That fig has since been eclipsed by the 2023 wildfire season, which saw much than 28,000 quadrate kilometres of onshore burned successful the province. A further 10,800 quadrate kilometres burned past year.

The insubstantial cites probe showing atmospheric rivers are becoming much predominant and terrible with clime change, which is besides fuelling progressively aggravated wildfires.

It says these trends "will apt pb to an summation successful geohazards" successful B.C.

Tannant said B.C. needs to hole for much geohazards successful the aboriginal but noted it volition beryllium hard due to the fact that of existing infrastructure and communities surviving successful those areas.

"There astir apt needs to beryllium adjacent much resources enactment upon determining where are these hazardous locations and what tin we bash to mitigate immoderate of the hazards," helium said.