Canada: Adverse winter weather forecast across parts of southeastern regions through at least March 12 /update 1

Adverse winter weather is forecast across parts of far southeastern Quebec Province and Newfoundland Island through at least March 12. A storm system is forecast to bring heavy rainfall, snowfall, and thunderstorms. Heavy downpours may trigger flooding in low-lying areas, and strong winds may cause property damage and power outages. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming hours.

As of late March 11, Environment Canada has issued the following warnings:

• Red rainfall warnings: eastern Newfoundland Island. 3-5 cm (1-2 inches) of rainfall is forecast. Significant runoff is likely as the rain combines with mild temperatures and strong winds to cause considerable melting of the snowpack from the recent winter storm.

• Red snowfall warnings: Deer Lake and vicinity, Buchans and the interior, Green Bay to White Bay, and south of Hare Bay on the Great Northern Peninsula. 15-25 cm (6-10 inches) of snowfall is forecast, with 30-50 cm (12-20 inches) over higher terrain.

• Red winter storm warnings: far southeastern Quebec Province. Additional snowfall of 15-30 cm (6-12 inches) with wind of up to 90 kph (56 mph) are forecast.

• Red wind warnings: the Blanc-Sablon area of Quebec Province.

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, as well as 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 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 will likely cause some delays and cancellations at airports in the region. Flooding or snow could block regional rail lines; freight and passenger train delays and cancellations are possible in areas that see heavy rainfall or snowfall due to potential track blockages.

Disruptions triggered by inclement weather and resultant hazards, such as flooding or snowfall accumulations, 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.