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Unstable ground, heavy rainfall puts train lines, mountains roads at risk: expert

Last Updated Feb 3, 2020 at 11:17 am PDT

A landslide took out part of the only access road to Sasquatch Mountain, stranding hundreds of people at the top of the resort on Friday. (Ryan Smith, submitted photo)
Summary

With about 140 to 150 per cent more rain than usual last month, the ground has become more saturated and unstable

An expert says more precipitation could cause more flooding and landslides

Train lines and mountain roads are particularly at risk during heavy rainfall

VANCOUVER (NEWS 1130) — Landslides have taken out roads, phone lines, power, and train tracks across the South Coast after an exceptionally rainy January.

With about 140 to 150 per cent more rain than usual last month, the ground has become more saturated and unstable. Over the weekend, a landslide hit trapping hundreds of people at an Agassiz resort. About 250 people have been helicoptered out of the area since Friday.

Brent Ward, co-director of the Centre for Natural Hazards Research at Simon Fraser University, says more precipitation could be problematic.

“Things are really wet, so if we get another big system in the next week or two, I mean, we could see a similar response in terms of landslides and flooding,” he tells NEWS 1130.

During heavy rainfall, Ward explains train lines and mountain roads are particularly at risk considering the surrounding area.

RELATED: Liberal MLA calls out government for lack of action to help those stranded on Sasquatch Mountain

“A lot of the places where we’ve had troubles there’s a deep slope of unconsolidated material, so it’s not bedrock. That material gets saturated, and then it fails. Of course with the railroad, you have to stop. You have to clean it up,” he says.

Most of the road erosion comes from clogged culverts, which means water is more likely to wash out a road as it has nowhere to go during a storm, according to Ward. He argues flooding should be considered in future design of infrastructure.

“When we put houses and roads on the landscape, that water doesn’t absorb and it gets dumped into creeks very quickly and that causes the creeks to increase their levels very quickly during a rainstorm event but not have the stored water in the summer when we need that groundwater recharge to keep creek levels high.”

Ward notes some new developments, though, have implemented these considerations and design roads to absorb the material.