Canada: Water surpluses to increase from Toronto to Lake Huron

30 May 2019

THE BIG PICTURE
The 12-month outlook for Canada through January 2020 indicates widespread water deficits of varying intensity, with vast pockets of exceptional deficit in Quebec, Ontario, and Manitoba.

A large block of exceptional surplus is forecast surrounding Fort McMurray, Alberta leading east past Churchill Lake, Saskatchewan. Surpluses of generally lesser intensity are forecast along the border of British Columbia and Alberta near Fort St. John in the north and in southeastern British Columbia. At the opposite end of the country, surpluses are expected in southern Ontario from Toronto to Lake Huron, in southern Quebec around Montreal, and at the mouth of the Saint Lawrence River near the Manicouagan River.

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

The forecast through July indicates that deficits will emerge in much of Northern Ontario (ON), transitioning from surplus in some areas. Widespread, exceptional deficits in northern Quebec (QC) will shrink. In southern Quebec, from the westernmost point of the Ottawa River stretching east to the Gulf of St. Lawrence, conditions will transition out of exceptional surplus to milder anomalies, while conditions around Montreal and near Ottawa will transition to moderate surplus. Surpluses will increase and intensify from Toronto to Lake Huron.

Moving west, deficits are forecast for nearly all of Manitoba (MB), including large pockets of exceptional deficit along Hudson Bay and spanning the province’s central region north of Lake Winnipeg. Moderate deficits are expected in southern Manitoba and southern Saskatchewan (SK). In Alberta (AB), extreme deficits are forecast in the far northwest corner and in the Middle Reaches of the Athabasca River Watershed. A vast block of exceptional surplus is forecast in the Upper Reaches of the Athabasca surrounding Fort McMurray and leading across the border into Saskatchewan. In British Columbia (BC), surpluses will increase in the southeast but diminish in the north along the Peace River from Fort St. John and around Williston Lake. Intense deficits will persist on Vancouver Island.

From August through October, anomalies will downgrade overall. Moderate surpluses will persist around Montreal and Ottawa, and more intense surpluses from Toronto to Lake Huron. Surpluses in southeastern BC will nearly disappear, and the vast block of intense surplus across the northern border of Alberta and Saskatchewan will begin to transition, with conditions of both deficit and surplus (purple).

The forecast for the final three months – November 2019 through January 2020 – indicates moderate deficits spanning the central regions of the Prairie Provinces and much of Northern ON. Surpluses are forecast for pockets of southern BC, a block in SK’s far northwestern corner, and scattered in eastern QC following the St. Lawrence River.

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

IMPACTS
Floods ravaged eastern Canada late last month following heavy rains and melting snow, killing a woman who drove into a sinkhole carved by a washed out road. Hundreds of homes were flooded in Quebec, prompting hundreds of military troops to be deployed to help evacuate homes. The city of Ottawa declared a state of emergency this month when rains continued, raising water levels by 8 cm (3.15 in) in 24 hours. As rainwater cycled into the Ottawa River, water levels broke a 59-year-old record.

The floods inundated over 600 square kilometers (232 square miles) of land in Manitoba, New Brunswick, and Quebec, including 153 square kilometers (59 square miles) of agricultural zones. Nearly 460 kilometers (286 miles) of roads were either cut off or washed out. Economic losses are expected to reach into the hundreds of millions of dollars, most of which are uninsured.

Most of British Columbia is abnormally dry or in a drought, prompting a ban on campfires in the northwestern region of the province. Snowpack levels in British Columbia are the lowest recorded in mid-May in the past 40 years, due to a warm spring which caused early snow-melt.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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