Experts warn heavy rain and snow creating 'perfect' conditions for landslides

This season's snowfall — combined with heavy rain we've seen in recent days — has increased the risk of landslides in parts of the Lower Mainland.

"These are pretty well perfect conditions for a variety of landslide types," said Brent Ward, professor of Earth Sciences at SFU.

"When we have this much snow on the ground and a fairly significant rainstorm causing a lot of rain and then melting the snow, we can get very saturated conditions, which can trigger debris flow as well as rock flows and rock slides."

Ward said areas to monitor are places near mountain fronts, such as the Sea to Sky highway and Highway 1 near Hope. They are places that could see rock slides or debris flow.

"I was pretty sure we were going to get some landslides with this storm event, but I think the rainfall totals have been a little bit lower than they initially predicted."

While an Environment Canada rainfall warning has ended in Metro Vancouver, there is still rain in the forecast for the coming days.

Warning signs

Erik Eberhardt, director of Geological Engineering at UBC, said one of the key triggers for a landslide is water in the ground.

"The concern at the present is that we have a double hit: we had stored water in the form of snow and as that melts that's going to be a release of water. And then we have precipitation on top of that," said Eberhardt.

While there isn't a dedicated body that actively monitors vulnerable areas, he said there are warning signs that people can look for.

"What we try to do is educate people in terms of what signs they would be looking for that might show that the ground might be unstable or moving," said Eberhardt.

"That would be things such as cracks opening up in streets or in pavement or in their yards, trees that are tilting along paths that they might be going for a walk along."

Eberhardt said people should be more alert than normal at this time, especially if they're in vulnerable areas and if there's a known hazard that could impact their property.