Canada: Water surpluses forecast in southern QC, deficits in center & north

25 May 2017

The Big Picture
The 12-month outlook for Canada through January 2018 (below) indicates deficits throughout Quebec, with exceptional deficits across the center of the province, along the border into Ontario, and in northeastern Manitoba along Hudson Bay.

Moderate to exceptional deficits are forecast in central and northwestern regions of Alberta and British Columbia. Surpluses are forecast for central Manitoba west of Lake Winnipeg; a large block of northwestern Saskatchewan into Alberta; and southeastern British Columbia.

Impacts
Melting snow combined with torrential rainfall produced massive flooding across southern Quebec and Ontario in late April into May, with early estimates of economic losses into the millions of dollars USD according to global reinsurance broker Aon Benfield. At the start of May the water level of Lake Ontario measured 55 centimeters (21.7 inches) above average for that time of year. In Quebec 187 municipalities in at least 8 regions - Mauricie, Montréal, Outaouais, Laval, Lanaudière, Laurentides and Montérégie - were affected. Over 4,400 homes flooded, 3,600 people were evacuated, and travel on 522 roads was hindered. The Canadian Army Forces deployed some, 1,800 troops to assist with sand-bagging and evacuation. One death was confirmed and a two-year old child remains missing, presumed dead.

As of May 22, over 5,000 residents of Quebec had not been able to return to their homes, and by May 10 over 700 applications for financial aid had been submitted by flood victims under Quebec's “General financial assistance program regarding actual or imminent disasters.” Following the disaster compensation for home damage was increased to $200,000 (USD$148,629), a $40,000 (USD$29,721) increase. Residents whose homes were located in a 0-20 year flood zone will not be able to rebuild in the same location, as stipulated in provincial legislation.

"The Beast" - Alberta's May 2016 Fort McMurray wildfire that forced the evacuation of 80,000 people, blazed through 590,000 hectares (1,500,000 acres), and destroyed 2,400 buildings - continues to haunt survivors, many of whom now suffer from PTSD. Seven researchers from Canadian universities will share $3.4 million (USD$2.5 million) in funding to study health impacts of the fire, including $1 million (USD$745,084) earmarked specifically for mental health effects.

The Alberta government has approved more than $7 million (USD$5.2 million) in tax relief for those whose property was affected in the Fort McMurray fire. The provincial government will also quadruple funding for wildfire prevention, increasing the FireSmart program from $3.8 million (USD$2.8 million) to $15 million (USD$11.2 million) annually, and has appropriated $10.5 million (USD$7.8 million) over three years specifically for fire prevention in the Fort McMurray area.

On the other end of the natural hazards spectrum, the government of Alberta will invest $13.4 million (USD$10 million) to help the city of Calgary and neighboring communities prepare for flood events.

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

The forecast for May through July shows the emergence of deficits throughout northern Quebec; the persistence and expansion of exceptional deficits in central Quebec and along the border into Ontario; and moderate surpluses for southern Quebec. Much of Ontario is expected to transition from surplus to deficit, though surpluses will continue to emerge in the north along Hudson Bay. The extent of exceptional deficits in northeastern Manitoba on Hudson Bay is expected to increase. Moderate to severe deficits will persist in northwestern Alberta and expand southward, merging with persistent extreme deficits in the Upper Athabasca River watershed in central Alberta. Moderate to extreme deficits will persist in northwestern British Colombia, and exceptional deficits will emerge in greater extent in central BC in a large pocket surrounding Prince George.

Both deficits and surpluses are forecast for a large block in Manitoba between Southern Indian Lake and Split Lake. Exceptional surpluses are expected to persist between the northwestern shore of Lake Winnipeg across the border into Saskatchewan; a large block in northwestern Saskatchewan between Lake Athabasca and Churchill Lake and across the border to Ft. McMurray, Alberta; and southeastern British Columbia into southern Saskatchewan.

As seen in the August through October map the extent of exceptional deficits will diminish. Deficits across Quebec will diminish in extent and severity though patches of exceptional deficits will persist. Moderate deficits are forecast for much of Ontario with severe to extreme deficits just west of the Quebec border. In northeastern Manitoba the extent of exceptional deficits along Hudson Bay will diminish, leaving isolated pockets. Deficits in northern Alberta and British Columbia will diminish in severity leaving moderate deficits in Alberta, and more severe deficits in BC.

Severe to exceptional surpluses are expected from Ft. McMurray in Alberta across the border into northern Saskatchewan, with both deficits and surpluses from Lake Athabasca to Lake Churchill. Moderate to severe surpluses will emerge in northeastern Saskatchewan and continue east midway through northern Manitoba. Exceptional surpluses are expected to persist northwest of Lake Winnipeg.

After October the forecast indicates normal to moderate deficit conditions from Hudson Bay east, and similar conditions across the plains states with some persistent surpluses in aforementioned areas.

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