Canada: Water deficits in the Prairie Provinces to retreat

22 September 2017

The Big Picture
The 12-month outlook for Canada through May 2018 indicates large blocks of exceptional water deficit in central Quebec, northeastern Manitoba, southern Saskatchewan, central and northwestern Alberta, and central British Columbia.

Exceptional surpluses are forecast for central Manitoba west of Lake Winnipeg; a large block of northwestern Saskatchewan into Alberta; and small pockets in southeastern BC.

Impacts
Extremely dry conditions across central Canada's agriculturally productive Prairie Provinces have reduced estimates of durum wheat yield by as much as 44.6 percent, with 12.9 percent attributable to reduced acreage, according to Statistics Canada. In southern Saskatchewan spring wheat yield estimates are running 14 percent under last year, a decline offset by an 8 percent increase in harvested areas.

In the east, New Brunswick’s wild blueberry farmers suffered significant losses after a hot, dry summer. “Devastating,” lamented one farmer whose yield was down 50 percent. This season's low yields, along with other factors, could force some 200 wild blueberry growers out of business, says the New Brunswick Blueberry Growers Association.

And at the opposite end of the country, early this month British Columbia asked water users in the Lower Fraser region and on Vancouver Island to voluntarily reduce consumption by 30 percent in response to drought alerts in several area watersheds. On August 30 the Fraser River measured 20 percent lower than average for this time of year, making it more susceptible to temperature increases that threaten fish stock.

As Vancouver withered under the heat and drought, the Vancouver Park Board issued an appeal to residents to save young trees - planted as part of the city's urban forest initiative to increase the tree leaf canopy from 18 to 22 percent - by watering them or calling a hotline to report distressed trees.

Spring flooding in Ontario and Quebec resulted in at least C$223 million (US$180 million) in insured damage, reports the Insurance Bureau of Canada. April windstorms and floods in southern Quebec into Ontario were responsible for C$106 million, and May flooding in Eastern Ontario and Quebec accounted for C$117 million.

Forecast Breakdown
The 3-month maps (below) show the evolving conditions in more detail.

The near-term forecast through November indicates a significant retreat of exceptional deficits in the Prairie Provinces, particularly southern Saskatchewan. Extreme to occasionally exceptional deficits will persist in northeastern Manitoba. Moderate to severe deficits are forecast for much of Alberta, and a pocket of more intense deficits may emerge in the southwest near Banff National Park. Surpluses in northwestern Saskatchewan into Alberta will transition to conditions of both deficit and surplus as deficits emerge north of Lake Churchill, and a similar transition is forecast west of Lake Winnipeg in Manitoba.

Surpluses in Southern Ontario north of Kitchener and in Ottawa are expected to diminish; moderate to severe deficits are forecast for much of Northern Ontario. Moderate to extreme deficits are forecast to persist in New Brunswick and to emerge in neighboring Quebec east of the St. Lawrence River. The extent of exceptional deficits in southern Nord-du-Québec will diminish.

The bottom two maps, representing forecasts for the final six months, show a more subdued color range at least with regard to water deficits, indicating the near-absence of exceptional deficits. However, intense deficits are forecast to persist in southwestern Alberta north of Banff National Park through February 2018. Moderate to severe deficits are forecast in northeastern Manitoba and northern Ontario. Scattered surpluses are expected in southern BC. Some surpluses will re-emerge in Manitoba just west of Lake Winnipeg and in Saskatchewan west of Lake Churchill and across the border into Alberta, though both deficits and surpluses are forecast for surrounding areas.

The forecast for the final three months – March through May – indicates the increasing presence of moderate to severe deficits in northern portions of Alberta, Manitoba, and Ontario.

(It should be noted that forecast skill declines with longer lead times.)

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