British Columbia Photos

More than a few acres: the vital importance of snow to B.C.'s climate

How an ancient snow forest illustrates snow's importance to B.C.'s climate future

Roshini Nair - CBC News

June 22, 2017

This rainforest 600 kilometres away from the B.C. coast — near McBride — only sees about a third of the amount of rain as B.C.'s coastal rainforests. (Polly Leger/CBC)

Deep in B.C.'s Interior a very special 3,000-year-old rainforest is a living embodiment of the importance of snow to B.C.'s fresh water future.

The ancient cedar stand near McBride, B.C. — 600 kilometres from the coast — isn't really a rainforest at all, explains Darwyn Coxson, a professor in ecosystem science at the University of Northern British Columbia. 

ADVERTISEMENT

Rather, it's a "snow" forest.

Unlike B.C.'s coastal rainforests on Haida Gwaii or Prince Rupert which are fed by constant rain, the trees in this stand only see about a third of the amount of rain those forests do.

"Snow is what sustains it. The snow is what keeps it alive," he said.

"As that melts it recharges the groundwater, and the places where the ancient cedars grow are right at the base of the mountain slopes."

The ancient forest (see purple icon) is located near Prince George in B.C.'s northern Interior. (Google Maps)

Climate change could have a devastating impact on this forest.

"The winters have become dramatically warmer. We've had shorter winters. It melts out earlier in the spring [with] more rain," Coxson said. 

"I looked at the snow payload data from the environment this morning. The snow pillow data from the nearest mountain peak to here is at a record low. And I thought the low snowpack last year was tied for the record low, but we're below the lowest ever recorded snowpack here."

The rainforest near McBride relies on snow for its water. (Polly Leger/CBC)

At the same time, the summers have gotten wetter. 

Stephen Dery, a professor of environmental science and engineering at UNBC, says the summer rain doesn't make up for the lost snow. 

"When rain falls on the ground, it will essentially go straight into the creeks and rivers and the Fraser River," he said. 

"If the precipitation occurs in winter, then that's going to run off right away and not accumulate in the snowpack and build up that water resource that we would normally expect to to have accumulated by the end of the spring and melt during the summer."

UNBC Professor Darwyn Coxson says the snowpack has been shrinking for years. (Polly Leger/CBC)

A lack of a snowpack goes beyond this tree stand, Dery says.

Snow in this area feeds the Fraser River — the largest river basin in the province — which runs through some of the most densely populated parts of the province, he explained.

"It spans 340,000 square kilometres ... I mean we can compare that to the size of the United Kingdom, so it can be the size of a European country," Dery said. 

With less snow and more rain in the winter, he said, flows to the Fraser River could be higher in the winter and lower in the warmer spring and summer. 

"Lower flows typically will mean warmer water temperatures, and warmer temperatures are not good for salmon ... so reduced snowpacks will have a huge impact in terms of the ecosystem as well." he said. 

Without the snow slowly melting and replenishing groundwater throughout the year, Dery says the water supply all the way to Delta could be affected. 

Rain enters rivers and creeks more rapidly than snow which melts slowly into groundwater, replenishing the water table at a more gradual rate. (Darwyn Coxson)

According to Deborah Harford, who runs the Adaptation to Climate Change Team out of Simon Fraser University's School of Public Policy, there will need to be infrastructure changes to everything from aquifers to sewage pipes to deal with shifts in precipitation. 

While B.C. might not be affected by a lack of water resources, surrounding areas — like Washington, Oregon, and California — will put pressure on our water resources.

"The southern part of the Columbia Basin [in the United States] is forecast to have about a 50 percent drop in stream flow by 2050, so by mid-century there's going to be a crisis down there, because they have a $5 billion irrigated agriculture industry, and they're going to need to get that water from somewhere," she said. 

"We need to value water more. We waste a great deal of it," she said. 

The snow pack from this area feeds the largest river basin in the province — the Fraser River. (Shutterstock)

Listen to 2050: Degrees of Change, a CBC Vancouver podcast 

With files from Polly Leger and Johanna Wagstaffe

Start the day smarter
Get the CBC News Morning Brief, the essential news you need delivered to your inbox