Canada: Severe weather forecast across parts of western Ontario through at least early May 23

Severe weather is forecast across parts of western Ontario through at least early May 23. A low-pressure system is expected to bring heavy rainfall and strong winds across the region over the coming days. Rainfall totals of 3-8 cm (1.2-3.1 inches) and winds gusting up 70 kph (43 mph) are expected across the affected area. Heavy downpours may trigger flooding in low-lying areas, and strong winds may cause property damage and power outages.

As of May 21, Environment Canada has issued red rainfall warnings (the highest level on a three-tier scale) across much of the region, with the exception of southwestern parts of the affected area, where grey special weather statements are in place. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming hours.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where the soil has become saturated by heavy rainfall. Disruptions to electricity and telecommunications services are possible where significant flooding, landslides, or strong winds impact utility networks.

Floodwaters and debris flows will likely render some bridges, rail networks, or roadways impassable, impacting overland travel around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger intermittent flight delays and cancellations at airports in the region though these are unlikely to be severe or prolonged. Authorities may temporarily suspend port operations if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas that see heavy rainfall and potential track inundation. Localized business disruptions may occur in low-lying areas.