Massive Flooding in Calgary, Canada
Torrential rainfall on Wednesday night and Thursday has resulted in the most extensive flooding in Alberta Province, Canada in at least 8 years. Some 100,000 people are facing evacuations in the city of Calgary. Here is a brief summary of the event. There have so far been confirmed reports of two fatalities.
Mandatory evacuations of downtown Calgary (Canada’s 5th largest city) are currently taking place and most of the city has lost its electricity following massive flooding along the Bow and Elbow Rivers which course through the city and its environs. The city’s Centre Street Bridge and most of Calgary’s other landmarks, including the zoo on St. George’s Island, are under water this Friday.Downtown Calgary under floodwaters this Friday morning (June 21st).
Photo by Esther Madziya.
This YouTube video by James Black shows water flooding the highway along Crowsnest Pass west of Calgary.Cause of the flood
Heavy rainfall began falling across the Bow River Basin on Wednesday night with up to 190 mm (7.51”) falling in some areas over just a 24-hour period. However, it was the widespread nature of the heavy rainfall, with an average of 50 mm (2”) blanketing the entire river basin that has led to the massive flooding.These two maps show the boundaries of the Bow River Basin where the worst of the flooding is taking place. The Elbow River flows to the south of the Bow River and the two rivers converge in Calgary. Although not named on either of these maps, the course of the Elbow River can be found by the location marked Bragg Creek on the top map.
Maps from The Weather Network.River flow rates on the Elbow River at Bragg Creek have reached 500 cubic meter/second which is 20 times the average flow rate. The record flow rate here was 836 m3/s in 1932.A still from a dramatic video of the raging waters of the Elbow River near Elbow Falls.
Videographer not yet identified.Radar estimated precipitation totals for the 24-hour period ending 8 a.m. on Thursday June 20th when the bulk of the rainfall occurred. Isolated amounts of over 200 mm (about 8”) are evident in the mountains southwest of Calgary
Environment Canada.Actual measured rainfall totals for the area over 60 hours ending 9 a.m. Friday, June 21st. The vast majority of these totals occurred in just a 12-hour period Wednesday night and Thursday morning.
Data from Environment Canada.
The all-time calendar day rainfall record for Calgary Airport is 95.3mm (3.75") on July 15, 1927 and the June daily record 2.56" on June 18, 1918.
For the latest updates on the situation in Alberta see the Canadian weather website The Weather Network.Video 1.
Flood waters on Bragg Creek in Alberta, Canada send a house hurtling into a bridge on June 20, 2013. Warning" one s-word expletive.
Christopher C. Burt
To Rob Davis, meteorologist at The Weather Network in Canada for much of the above information and graphics.