Smaller snowpack threatening Fraser

A new study shows the volume of the mountain snowpack feeding B.C.'s largest watershed has dropped by almost one fifth over a six-decade period.

That snow used to supply the vast majority - 70 per cent - of the Fraser River Basin's annual flow.

article continues below

Now that's dipped to half, with the rest made up of rainfall, according to a University of Northern B.C. study published Wednesday in Nature Publishing Group's Scientific Reports journal.

It's part of a trend of shorter, warmer winters and drier summers, thanks to rising air temperatures, shifts in rainfall timing, and a decline in snowfall. It means, on average across the basin, the snow melts 10 days earlier.

That presents problems for salmon: with less water flowing through habitats in the summer, the water warms, making it more difficult for salmon to survive.

When UNBC researchers started looking at trends in the Fraser River's daily flow, they expected to see a decline in both snowpack and snowmelt.

"I think what is shocking is just how much that has changed," said environmental science professor Stephen Dery of the 19 per cent drop.

"That's a very large decline. That's very significant."

Dery led the research over a three-year period, collecting data upstream at the Fraser River at Shelley and the Thompson River near Spences Bridge. They looked at the Fraser River's main stem and six of its major tributaries between 1949 to 2006.

Interestingly, even as the snowpack decreased, the actual volume of water entering the Fraser River has remained fairly static.

"We're seeing more rainfall than we have in the past, so it's compensating for that loss of snow," said Dery.

"There is indication that the Fraser River is now transitioning from a snow-dominated regime to a hybrid one - in other words heading more towards a rainfall-dominated system."

Rainfall can be less predictable than snowfall or snow melt, he said. Also, timing becomes an issue.

"We're seeing more streamflow happening during the winter and much less in the summer and that's our dry period," he said.

That has a direct impact on water management in cases like the Nechako reservoir, for example, with a need for storing more water in the winter to account for lower levels in the summer.

"Look at the snow conditions outside today and that's possibly what we're going to experience in the future," he said, which affects recreational use of the region for activities like snowmobiling and backcountry skiing.

It could also speak to the dropping mountain caribou populations, which depend on heavy snowpacks to reach boreal lichen, he said.

"If there's much less snow then they're going to have a hard time feeding so perhaps the decline in mountain caribou may actually be associated with this decline in snowpacks."

Read Related Topics


NOTE: To post a comment you must have an account with at least one of the following services: Disqus, Facebook, Twitter, Google+ You may then login using your account credentials for that service. If you do not already have an account you may register a new profile with Disqus by first clicking the "Post as" button and then the link: "Don't have one? Register a new profile".

The Prince George Citizen welcomes your opinions and comments. We do not allow personal attacks, offensive language or unsubstantiated allegations. We reserve the right to edit comments for length, style, legality and taste and reproduce them in print, electronic or otherwise. Comments that contain external links will not be permitted. For further information, please contact the editor or publisher, or see our Terms and Conditions.

comments powered by Disqus

Premier of Alberta POLL

Do you think Jason Kenney’s election as premier of Alberta is good or bad news?

or  view results

Sign Up For Our e-Newsletter!
  • 97/16

    Prince George's Weekly News

Popular Citizen

Community Event Calendar

Find out what's happening in your community and submit your own local events.

Lowest Gas Prices in Prince George
Prince George Gas Prices provided by