Canada: Adverse weather forecast across eastern regions through at least Dec. 12

Heavy rainfall, heavy snowfall, and strong winds are forecast across parts of eastern Canada through at least Dec. 12. As of late Dec. 10, Environment Canada has issued the following warnings:

• Red rainfall warnings (the highest level on a three-tier scale): most of New Brunswick, from Red Bay to L'Anse-au-Clair in Newfoundland and Labrador, and far southeastern and far southern Quebec. Up to 7 cm (3 inches) of rainfall is forecast. The rain is likely to change to snow over parts of northwest New Brunswick before easing late Dec. 11.

• Red snowfall warnings: southern Quebec and Churchill Fall, Churchill Valley, Hopedale and vicinity, and Postville to Makkovik in Newfoundland and Labrador. Snowfall of up to 20 cm (8 inches) is forecast.

• Red winter storm warnings: Upper Lake Melville, Rigolet, and their vicinities in Newfoundland and Labrador. Snowfall of 15-20 cm (6-8 inches) is forecast.

• Red wind warnings: southern New Brunswick, Nova Scotia, Prince Edward Island, and far southeastern Quebec as well as western Newfoundland Island.

• Red storm surge warnings: far southeastern Quebec; across Forillon Park, Gaspe, Perce, Chandler, Natashquan, Chevery, and Blanc-Sablon.

• Yellow winter storm watch: Nain and vicinity in Newfoundland and Labrador.

• Grey special weather statements for heavy rain and strong winds: Trans-Labrador Highway from Upper Lake Melville to Cartwright and Cartwright to Lodge Bay in Newfoundland and Labrador.

Officials may update and extend the coverage of weather alerts over the coming hours.

The storm system could produce rounds of heavy precipitation (including rain and snow) and strong winds across the affected area. Where precipitation falls as rain, flash and areal flooding is possible. Such flooding is possible in low-lying communities near watercourses and other large bodies of water and in urban areas with easily overwhelmed stormwater drainage systems. Sites downstream of large reservoirs may be subject to flash flooding after relatively short periods of intense rainfall. Precipitation could fall as snow in northern parts of the affected area over the coming days. Wind gusts could cause blowing and drifting snow; decreased visibility is likely in these areas.

Floodwaters and related debris may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around the affected area. Flooding in urban areas could also result in significant traffic congestion. Heavy snow will likely make driving hazardous in some areas; authorities could implement temporary road closures or detours in such locations

The disruptive weather could cause delays and cancellations at regional airports. Authorities may temporarily suspend port operations in coastal areas if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding or snow could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and potential track blockages.

Disruptions triggered by inclement weather and resultant hazards, such as flooding or strong winds, could persist well after conditions have improved - it could take days before any floodwaters recede and/or officials clear debris. Repair or reconstruction efforts may result in residual disruptions if there is severe damage to infrastructure.