B.C. communities struck by wildfires and floods brace for spring thaw

Alanna Cowan has watched the Nicola River in British Columbia's Interior turn the colour of chocolate milk and rise every spring, as warm weather melts snow from the surrounding mountains.

It is part of an annual cycle that can cause minor flooding, but Cowan said this year feels more uncertain.

Major wildfires, droughts and mudslides last year dramatically altered the landscape, raising questions about the river's ability to handle the spring thaw, or freshet.

"When we talk to our elders, you know, and look back in history, [there's] nothing like this,'' she said of the disasters that forced Cowan from her home twice last year.

"Everybody's wondering, when spring thaw happens here, what's coming down off that mountain and how hard is it going to come down?''

The Nicola Valley is one of many regions in British Columbia still recovering from last year's extreme weather as the thaw begins.

Although the federal and provincial governments have pledged funds to guard communities from the effects of climate change, most protection measures won't be in place in time for this season.

Forecasters say it's difficult to predict flooding more than a few days in advance, so residents should always be prepared.

"There are changes this year that may alter the kind of risks that are out there,'' said Dave Campbell, head of B.C.'s River Forecast Centre.

Spring flooding generally depends on a combination of factors, including the level of snowpack, temperature and other variables like heavy rainfall, he said. It typically peaks in May and June.

The forecast centre's monthly report released April 8 says there is a slightly elevated risk of freshet-related flooding this spring depending on weather, with snowpack levels averaging near normal across the province.

However, regions of British Columbia that experienced both wildfires and floods, like the Fraser Canyon and Nicola River and their tributaries, have "overlapping risks,'' Campbell said.

Snowmelt runs over scorched land more rapidly, for example. And rivers like the Nicola that changed course and filled with sediment will make predictions more challenging, he said.

"We try to focus mostly on the flow side of things because that's what we can get a handle on, but when there is a channel change, it can be very difficult to understand the flow, what that means for the on-the-ground conditions,'' Campbell said.