Canada: Severe weather forecast over parts of southwestern Alberta and southern and southeastern British Columbia through early Sept. 26

Severe weather is forecast across parts of southwestern Canada through at least early Sept. 26. A cold front is expected to bring heavy rainfall, thunderstorms, and strong winds to parts of southern and southeastern British Columbia through Sept. 25, and strong winds are likely to impact parts of southwestern Alberta through early Sept. 26. Rainfall totals of 5-7 cm (2-2.8 inches) and winds gusting up to 100 kph (62 mph) are possible across parts of the affected region.

As of early Sept. 25, Environment Canada has issued red rainfall warnings (the highest level on a three-tier scale) for North Columbia and Kinbasket forecast districts in British Columbia and red strong wind warnings for parts of southwestern Alberta. Authorities have issued a grey special weather statement regarding the adverse weather associated with the cold front across the Fraser Canyon, North and South Thompson, Nicola Valley, Similkameen, Okanagan Valley, Shuswap, Columbias, Kootenays, and Yellowhead areas of British Columbia, 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 areas, especially where heavy rain has saturated the soil.

The severe weather could contribute to transport disruptions throughout the region. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and 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. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and potential track inundation.

Localized business disruptions could occur in flood-hit areas; some businesses might not operate at full capacity because of damage to facilities, possible evacuations, and some employees' inability to reach work sites. Strong winds could also cause power outages.