Friday July 31, 1987 is more commonly referred to as "Black Friday" by Edmontonians who were witness to the most devastating day in the city's history.
It all started on a day that was anything but a usual Friday in Alberta's capital city. The atmosphere had all of the needed ingredients to cause concern for meteorologists, and the public. In the days before, warm and humid air was being funneled into central Alberta due to a low-pressure system over southwestern British Columbia. As well as this, warm temperatures, and near record-breaking dew-point temperatures created thunderstorms in the days before July 31 and as a result, all of these ingredients added an intense amount of instability in the atmosphere. To make matters worse, on Friday July 31, the warm moist air collided with a cold front in western Alberta.
This atmospheric set-up ultimately caused 8 tornadoes to occur on this date. However, the most notable one was the F-4 tornado that at 3:04 p.m. MDT touched down near Beaumont, and continued northward into the southeast portion of Edmonton. After ripping through numerous neighborhoods, at 4 p.m. MDT mother nature would save its final, and most deadly blow for a trailer park called the Evergreen Mobile Home Park in the city's northeast corner. Close to 200 mobile homes were completely destroyed, leaving 15 dead, and many others injured in its wake.
Overall the tornado outbreak lasted from 2:55 p.m. MDT until 8 p.m. MDT, killing 27, and leaving close to 300 people injured. Thus, more than half of the total fatality count occurred in the Evergreen Mobile Home Park. As well as this, the central Alberta tornado outbreak caused approximately $332 million dollars in damage, and had peak winds measuring at 417 km/h. These winds were very close to the 420 km/h F-5 wind threshold (based on the old F-5 rating system) however, the tornado was ultimately considered an F-4 rating despite some scars on the ground and wind distribution of debris showing F-5 rating characteristics.
As a result of "Black Friday", the Emergency Public Warning System was created, however in October 2011 this system was switched to Alberta Emergency Alert system. Another meteorological advancement that came from the July 31 central Alberta tornado outbreak, was the installation of the Doppler radar in Canada. While these advancements are saving more lives today, they unfortunately were created becasue of tragedy.
"Black Friday" will forever be in Canadian history for being the second deadliest tornado, the most costliest tornado, and one of Canada's worst natural disasters.
Friday July 31, 1987 is a date that residents who live in Edmonton and surrounding areas will always remember, as this is a day that mother nature not only changed lives forever, but also rewrote Canadian History.
Operational Forecaster - Christopher Poitras