Unusually skimpy snowpack levels now may mean trouble later in the summer for sockeye salmon that depend on adequate river flows to migrate.

Low snowpack in southwest B.C. ‘scary’ for salmon

Lower Fraser has 28 per cent normal snow, creating risk of low river flows and warm temperatures for sockeye this summer

The snowpack in southwestern B.C.’s mountains has been pushed further into record low territory by continued warm and dry weather.

The Lower Fraser watershed is now at 28 per cent of its normal snowpack for this time of year, down from 45 per cent a month ago.

And it’s even lower just to the west at 21 per cent on Vancouver Island and just 15 per cent in the South Coast region, which includes Squamish and Whistler.

B.C.’s River Forecast Centre called the readings “extremely low” in its latest snow level bulletin posted March 9. Most test sites in the three regions are at lows never before seen.

It’s impossible to guarantee there will be no spring flooding on the Lower Fraser – there are still close to normal snowpacks in the mid and upper sections of the watershed and a fast melt of what’s left can’t be ruled out.

But River Forecast Centre officials say there’s a below normal risk of seasonal flooding because the watershed as a whole is 84 per cent of normal, one of the lowest years on record.

They predict low flow conditions on rivers will come earlier and be more severe unless there’s significant rainfall this spring and summer.

Watershed Watch Salmon Society executive director Aaron Hill said that could mean trouble for returning sockeye salmon that may encounter dangerously warm river temperatures and low water levels that impede their migration.

“It’s definitely a scary situation for salmon this year,” Hill said. “Especially those stocks – like Fraser sockeye – that have long migrations to make later on in the summer, when the water gets low and it really heats up.”

Warm water temperatures stress salmon and can also make them more susceptible to disease.

Nor is the snowpack the only adverse environmental factor for salmon.

The same El Niño weather pattern responsible for the mild winter has also warmed ocean temperatures. Hill said that’s brought certain salmon predators, such as mackerel, further north than usual.

“If we end up having a hot summer that warms up those rivers then it’s a triple whammy,” Hill said. “We need to cross our fingers and hope for cool weather this summer and some rain.”

Environment Canada is forecasting a high likelihood of above-normal temperatures from March through May.