Canada: Severe weather forecast over central and northeastern Alberta and northwestern and central Saskatchewan through at least early July 27 /update 1

Thunderstorms and heavy rainfall are forecast across parts of central and northeastern Alberta and northwestern and central Saskatchewan through at least early July 27. Strong winds, lightning, hail, and possible tornadoes may accompany storms. As of July 25, Environment Canada has issued red heavy rainfall warnings (the highest level on a three-tier scale) across central and northeastern Alberta; rainfall totals of 7-9 cm (2.8-3.5 inches) with localized higher amounts of over 10 cm (3.9 inches) are possible in the affected areas. Red severe thunderstorm warnings are in effect over northwestern and central Saskatchewan, while red wind warnings are in place across central Alberta. 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 located 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.

Severe weather may trigger flight delays and cancellations at airports across the affected region. 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.