Canada: Exceptional water deficits to retreat in Prairie Provinces

25 August 2017

The Big Picture
The 12-month outlook for Canada through April 2018 (below) indicates large blocks of exceptional water deficit in central Quebec, eastern Ontario, northeastern Manitoba, southern Saskatchewan, and central Alberta and British Columbia.

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

Impacts
Agricultural experts have reduced their forecast for the Canadian canola harvest by 400,000 tonnes to 18.6m tonnes due to drought conditions in parts of the Prairie Provinces, and wheat projections have been lowered by 1.1m tonnes to a five-year low of 27.3m tonnes.

Regina, Saskatchewan saw its driest July in 130 years, creating hay and water shortages for livestock producers, withering crops, and causing power meters to ignite.

In British Columbia 19 wildfires have merged to create the largest wildfire in BC's history, the Plateau fire estimated at 467,000 hectares. Several rural communities in the Cariboo region have been evacuated and 400 firefighters and 25 of aircraft have been deployed. This year's wildfire season has been the worst recorded in the province: 1,031 fires since April 1 burning over 900,000 hectares. Smoke and aerosols from wildfires in the Northwest Territories prompted Environment Canada to issue health advisories.

Eastern provinces, too, are feeling the effects of much drier and hotter conditions. In eastern Quebec's Gaspé Peninsula grain and corn crops are stunted, the salmon catch is down 25 percent, and the bees have stopped making honey.

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

The near-term forecast – August through October – indicates a significant retreat of exceptional deficits in the Prairie Provinces, particularly southern Saskatchewan, though exceptional deficits will persist in northeastern Manitoba along Hudson Bay. Exceptional deficits will retreat slightly in Quebec but will persist in southern Newfoundland, and severe to extreme deficits will emerge east of the St. Lawrence River, in New Brunswick, and in southern Nova Scotia. Surpluses of exceptional intensity are expected to persist in central Manitoba west of Lake Winnipeg, a large block of northwestern Saskatchewan into Alberta, and in southeastern BC surrounding Kelowna. Surpluses will persist in Ontario near Ottawa and west of Toronto, but much of the remainder of the province will see deficits of varying intensity, particularly along the eastern border.

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. Moderate deficits are forecast during this period in central Alberta, northeastern Manitoba, and Ontario. Deficits of greater severity are expected in southern Nord-du-Québec. Exceptional surpluses are forecast to persist west of Lake Winnipeg in Manitoba, and in northwestern Saskatchewan and across the border to Fort McMurray, Alberta. These surpluses are expected to diminish in extent and severity in early 2018.

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

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