Friday, 7-31-1987. 30 years ago to this day is a day that many in the Canadian city of Edmonton refer to as 'Black Friday'. It is no wonder--as this day marks the anniversary of a violent F4 tornado that tore through the city, killing 27 people in its 19 mile path of destruction, and caused hundreds of millions of dollars in damage.
Weather forecasts issued during the morning and early afternoon of July 31, 1987 by Environment Canada revealed a high potential for unusually severe thunderstorms that afternoon, particularly for the Edmonton area due to a cold front that developed over western Alberta, colliding with the warm moist air that persisted over the region fom the previous week. The system in place had already set off a series of strong thunderstorms in the days prior. Forecasters recognized the elevated risk for severe weather early in the day.
Severe thunderstorms developed rapidly over the foothills early in the day and quickly moved eastward. The first severe weather watches were issued over central Alberta late in the morning and continued early in the afternoon. At 1:40 pm, a severe weather watch was issued for the Edmonton area, including Leduc County, Parkland County, and Strathcona County. The watch was later upgraded to a warning at 2:45 pm as the line of storms approached the area. As the cluster of storms approached the Leduc area, a violent cell rapidly developed ahead of the main line of storms and sharply turned northward. The storm passed east of Leduc, where the first tornado report made by a weather spotter at 2:59 pm. The tornado was on the ground briefly before dissipating. Shortly after 3:00 pm, another tornado touched down in the Beaumont area, tossing granaries and farm equipment as it grew in size and strength.
At 3:04 pm, a tornado warning was issued for the city.
The twister touched down to the south of Edmonton in the community of Mill Woods as a multiple-vortex tornado, causing F2 to F3 damage as it roared almost due north through eastern sections of the city . The tornado continued northward crossing the Sherwood Park Freeway and eventually hitting the Refinery Row area in east Edmonton at F4 intensity, where twelve people would lose their lives. The tornado tossed several large oil tanks, leveled several industrial buildings, and several trailers were picked up and scattered at Laidlaw and Byers Transport. Grass scouring and wind rowing of debris occurred, and damage in that area may have been borderline F5, but such a rating was never applied.
The tornado weakened slightly as it passed over an open area between Baseline Road and the North Saskatchewan River. It maintained F2 to F3 intensity as it tore through eastern parts of Clareview toward 4:00 pm, causing heavy damage to several homes as it paralleled a housing subdivision.
Near the end of its life, the tornado narrowed. A few blocks away, residents of the Evergreen Trailer Park got the worst of the twister. The storm killed fifteen people there and damaged 200 of the 600 mobile homes. Like the industrial areas and Refinery Row, some buildings were flattened while others were unscathed due to the multi-vortex nature of the storm.
On the ground for an hour, the Edmonton tornado was massive even by tornado alley standards. It remains the northernmost violent tornado in history, and the second deadliest tornado in North America during the 1980’s; only behind the Saragosa, Texas tornado that occurred just over 2 months earlier. Some articles have discussed the possibility of considerating upgrading this tornado's peak intensity to F5, a rating that was not previously applied to any tornado in Canada's history. No homes were swept away and no vehicles were reportedly carried more than 200 yards, however; two crucial factors as to why the tornado's rating was never revised. However, the unprecedented F5 rating that some suggested this tornado be upgraded to was seen nearly 20 years later when a narrow tornado grazed the outskirts of Elie, Manitoba. As of 2013, the tornado remained classified as a F4, and will remain as such with Environment Canada's adoption the Enhanced Fujita Scale, which does not revise the ratings of tornadoes prior to its implementation, leaving the possibility of a F5 rating open-ended.