Canada: Water deficit persists on the QC/ON border, surplus near Kelowna, BC

29 January 2018

THE BIG PICTURE
The 12-month outlook for Canada through September 2018 (below) indicates some exceptional water deficits in eastern Newfoundland; western Labrador around Churchill Falls; eastern Quebec at the mouth of the St. Lawrence River near Sept-Îles; northern New Brunswick; central Quebec and along the central Quebec/Ontario border; and on the southeastern and southwestern shores of Hudson Bay.

Severe to extreme deficits are forecast for the Quebec/Ontario border corridor; northwestern Ontario into central Manitoba; central Alberta west of Edmonton and northwestern Alberta; and large pockets in British Columbia surrounding Prince George and in the northwest.

Surpluses are forecast for central Manitoba west of Lake Winnipeg and into Saskatchewan; northwestern Manitoba; northwestern Saskatchewan around Churchill Lake westward to Ft. McMurray, Alberta; and near Kelowna, British Columbia.

IMPACTS
Data released by the British Columbia River Forecast Centre on 1 January indicates that snowpack levels in the Okanagan region near Kelowna are 123 percent above normal. Though high snowpack numbers do not necessarily portend future flooding, water managers in the area are especially alert after widespread flooding in the region last year.

Ice storms in British Columbia brought down trees and power lines in Fraser Valley, causing power outages for 120,000 in late December.

A so-called “bomb cyclone” battered Atlantic Canada early this month, causing extensive power outages and coastal flooding. Tens of thousands lost power in New Brunswick, Nova Scotia, and Prince Edward Island due to winds reaching 170 km per hour (105 mph) in some areas. Storm surge tore up roads and inundated homes in Nova Scotia, high winds toppled boats off their cradles in a Mahone Bay marina, and a Cape Breton fishing operation reported damage to its processing plant.

Dry conditions in western Canada last year, particularly in southern Saskatchewan, reduced yield of Canadian malting barley by 10.2 per cent, though crop quality was high. Regina, Saskatchewan recorded its second driest year ever in 2017, with 61 percent less precipitation than normal.

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

The near-term forecast, January through March, indicates a patchwork of water anomalies persisting in a pattern much the same as observed in the prior three months.

Deficits are forecast during this period for many areas, including (east to west): eastern Newfoundland; western Labrador; the mouth of the St. Lawrence River near Sept-Îles; the tip of the Gaspé Peninsula; northern New Brunswick; Nova Scotia; central Quebec surrounding Lake Mistassini and the Ontario/Quebec border corridor; the southeast and southwest shores of Hudson Bay; northwestern Ontario into central Manitoba; southern Manitoba and southeastern Saskatchewan; from Calgary, Alberta northeast past Lesser Slave Lake; from Banff into British Columbia; a pocket in BC surrounding Prince George, and northwestern BC.

Surpluses ranging from moderate to exceptional will continue to emerge in much of northeastern Quebec, and in a vast pocket of central Ontario where they are expected to be exceptional north of the middle stretch of the Albany River in Kenora. Exceptional surpluses are forecast west of Lake Winnipeg in Manitoba and into Saskatchewan; in northwest Manitoba; and in a large block surrounding Churchill Lake in Saskatchewan leading west to Ft. McMurray, Alberta, and south along the Beaver River in SK. Surpluses ranging from moderate to extreme are forecast along the central border of Alberta and British Columbia and west past Williston Lake. Surpluses in southeastern BC may be exceptional around Kelowna.

From April through June aforementioned areas of surplus in Quebec and Ontario will transition to near-normal conditions or moderate deficit, leaving both provinces with predominantly deficit conditions of varying severity. Some surpluses west of Lake Winnipeg in Manitoba will persist but will no longer extend across the border into Saskatchewan. Surplus conditions are also expected to persist near Churchill Lake in Saskatchewan and into Alberta, but the extent of exceptional surpluses will diminish. Surpluses of varying severity will continue to emerge in southern BC.

Many previously described pockets of exceptional deficit are expected to shrink overall, but intense deficits will continue to emerge in: western Labrador; central Quebec near Sept-Îles at the mouth of the St. Lawrence River; a small pocket along the central Ontario/Quebec border corridor; and at the southwest and southeast corners of Hudson Bay. Primarily moderate deficits will emerge in greater extent in Southern Ontario, reaching across the border through southern Quebec.

The forecast for the final three months – July through September – indicates mild to extreme deficits throughout much of country.

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

NOTE ON ADMINISTRATIVE BOUNDARIES
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