Thousands were being evacuated and others remain on alert, while heavily-traveled portions of several highways in western Alberta were closed due to heavy rain and flooding that occurred since the middle of the week and was still unfolding Friday.
A state of emergency was declared midday Thursday for the city of Calgary due to the possibility of major flooding along the Elbow and Bow rivers. Runoff was heading downstream from the foothills.
Rainfall on the order of 50 to 150 mm has fallen on part of western Alberta in the foothills and Rocky Mountains west of Calgary, Alberta, spanning Wednesday into Thursday night. Additional rain was falling Friday.
Evacuations were taking place in the Calgary area, including portions of the city core and multiple surrounding communities.
According to the Alberta Motor Association, Highway 1 was closed from the Highway 40 Junction to Banff due to flooding. Highway 1A was closed from Canmore to Morley due to flooding and washouts. Highway 40 was closed from Galatea to Kan Lake Trail due to flooding and mudslides. Highway 68 was closed from the Highway 1 junction to Gravel Pit Access. Highway 66 was closed from the Highway 22 junction to Park Gates.
In some areas, homes along streams and rivers were in danger of being swept away.
The torrential rainfall as well as locally severe thunderstorms were being caused by a strong storm system traveling along the U.S./Canada border this week. The same system has also had a history of heavy rainfall and severe thunderstorms over the northern Plains and Upper Midwest of the United States.
According to Canada Weather Expert Brett Anderson, "An additional 50 mm of rain can fall on these same areas into Friday afternoon."
The rainfall is forecast to dwindle later Friday as the storm system moves farther east.
This story was first published at 1:00 p.m. EDT, Thursday, June 20, 2013, and was updated at 10:00 a.m. Friday.