Cold weather increases flood risks in B.C.
Recent cold weather has piled snow onto mountains across the province at a time when the winter snowpack should be beginning to melt.
That means the lower reaches of the Fraser River could see high water if the weather doesn’t cooperate, says David Campbell of the B.C. Ministry of Environment’s River Forecast Centre.
At the beginning of April, snow packs in the Coast Mountain Ranges, Lower Mainland, and Fraser Valley were near normal levels.
However, since then, an unusually cold and wet April has increased the snow pack in the South Coast region to 145 per cent of normal as of April 15.
Vancouver Island, meanwhile, has experienced record levels of snow this winter, with snowpacks there at 167 per cent of normal.
“The weather over the next few weeks will determine the stream flow we’ll see,” said Campbell.
Should the weather stay cold and wet into May, and then quickly heat up, the snow could melt too fast, causing a potential flood risk.
“That’s when it becomes concerning,” he said.
The cold, wet weather this winter has been a result of the La Niña weather phenomenon, which is expected to subside by June.
The Fraser River experienced widespread flooding on its lower reaches in 2007, with water levels threatening to breach dikes in Maple Ridge and Pitt Meadows.
“We are no where near those levels right now,” said Campbell. “Right now we’re not anticipating that scale.”
The Harrison River, connecting Harrison Lake and the Fraser River, is expected to see particularly high volumes of water during the spring freshet, Campbell said.
However, small local rivers, such as the Alouette River and the Pitt River, will likely not be affected.
“The weather will be the key,” said Campbell. “But predicting it two months in advance is impossible, so we’ll have to wait and see.”