Canada: Water surplus to persist from Lake Huron to Toronto

18 July 2019

THE BIG PICTURE
The 12-month outlook for Canada through March 2020 indicates large pockets of exceptional water deficit in Quebec, Ontario, Manitoba, southern Saskatchewan, central and northern Alberta, and central British Columbia.

ISciences_Canada_Composite_Adjusted_201904-202003_12mo_panel.png

A large block of intense surplus is forecast surrounding Fort McMurray, Alberta leading north past Lake Athabasca and east past Churchill Lake, Saskatchewan. Surpluses of generally lesser intensity are forecast east of Fort St. John in northern British Columbia and in south-central BC. At the opposite end of the country, surpluses are expected in southern Ontario from Lake Huron to Toronto and from southern Quebec to the mouth of the Saint Lawrence River.

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

The forecast through September indicates that moderate surpluses will persist in southern Ontario (ON) from Lake Huron to Toronto but surpluses in southern Quebec (QC) through the Gaspé Peninsula, including the Gatineau River Watershed and Montreal, will nearly disappear. Large pockets of intense deficit will shrink somewhat but persist in QC west of Lake Mistassini, north of the Caniapiscau Reservoir, and around Sept-Îles at the mouth of the St. Lawrence River. Likewise, intense deficits along ON’s eastern border will shrink and downgrade slightly.

ISciences_Canada_Composite_Adjusted_201904-202003_3mo_panel.png

In the Prairie Provinces, deficits will diminish in southern Alberta (AB) and Saskatchewan (SK), but moderate to extreme deficits will persist in southern Manitoba (MB) including Winnipeg. Large blocks of exceptional deficit will persist north of Lake Winnipeg and along the western shore of Hudson Bay. A vast pocket of intense surplus will persist in northwestern SK past Fort McMurray, AB, and intense deficits will persist in northwestern AB and the Middle Reaches of the Athabasca River Watershed.

In British Columbia (BC), exceptional deficits are expected in southern Vancouver Island and severe deficits along the southwest border of BC. Intense deficits are forecast at the meeting of the Nechako and Fraser Rivers in the center of the province and the Skeena River region in the northwest. Surpluses are forecast south of Fort St. John in northeastern BC, and in the southern Columbia Mountains.

From October through December, the extent of both deficits and surpluses will diminish across the country, leaving nearly normal conditions in most major metropolitan areas. Deficits will persist west of Lake Mistassini and north of the Caniapiscau Reservoir (QC); around the southwestern edge of Hudson Bay and north of Lake Winnipeg (MB); in central and northwestern AB; and central and north-central BC. A large block of surplus will persist from northeastern AB into northwestern SK. Surpluses will moderate south of Fort St. John, BC and will persist in the southern Columbia Mountains.

The forecast for the final three months – January through March 2020 – indicates a forecast similar to the prior three months.

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

IMPACTS
The city of Hamilton has spent over $720,000 (USD $550,900) to repair flood damage along its Lake Ontario waterfront suffered over the last two years, and this year’s wet and windy conditions have only added to the damages. The additional costs of repairing the fresh damages will be clear only when the abnormally high lake recedes.

The Saskatchewan community of Swift Current lived up to its name when a 90-minute downpour of rain and hail flooded streets and overwhelmed the community’s sewer systems.

Damages resulting from this year’s spring flooding in Ottawa could cost the National Capital Commission $6 to $10 million (USD 4.6 to 7.7 million), including up to $4 million to fix the Portage Bridge alone. Spring floods caused nearly $208 million (USD $159.2 million) in insured damages nationally this year.

Forest fires in Alberta covering 300,000 hectares (741,300 acres) forced thousands of people to evacuate last month. The fires erupted amid the area’s driest conditions in 40 years, according to a provincial update.

The Vancouver Park Board is increasing efforts to strategically plant trees in urban parks that will be resilient to climate change, and especially to drought.

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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