After conducting a thorough analysis of the damage caused by the tornado that struck near Carstairs, Alberta on Canada Day, a team of experts from the Northern Tornadoes Project (NTP) and Environment and Climate Change Canada’s (ECCC) Prairie and Arctic Storm Prediction Centre has officially classified the tornado as an EF4.
According to a statement released by the NTP, the survey teams gathered sufficient evidence to determine that the tornado’s damage warranted an EF4 rating, with a maximum wind speed of 275 km/h. The preliminary assessment indicates that the tornado had a path length of 15.3 kilometers and a maximum width of 620 meters.
The destructive storm impacted a total of 12 homes in the area. Among them, three were completely destroyed, four were deemed uninhabitable, and five others suffered varying degrees of damage.
The EF (Enhanced Fujita) Scale, adopted in April 2013 as an improved version of the original Fujita Scale, was utilized to assess the tornado’s intensity. The EF Scale ranges from zero (weakest) to five (strongest). Environment and Climate Change Canada explained that the F-Scale, which was previously used to rate tornado damage, had limitations and lacked a comprehensive set of damage indicators. The EF Scale, on the other hand, considers a wider range of indicators such as residential and commercial structures, as well as vegetation. Additionally, the revised scale provides more accurate wind speed assessments based on damage analysis.
It is worth noting that the EF Scale’s damage ratings remain compatible with the original F-Scale, with the major changes being in the associated wind speeds. The implementation of the EF Scale allows for a more precise and comprehensive evaluation of tornado intensity and the subsequent damage caused.
F/EF Rating | F-Scale Wind Speed Rounded to 10 km/h |
EF-Scale Wind Speed Rounded to 5 km/h |
---|---|---|
0 | 60-110 | 90-130 |
1 | 120-170 | 135-175 |
2 | 180-240 | 180-220 |
3 | 250-320 | 225-265 |
4 | 330-410 | 270-310 |
5 | 420-510 | 315 or more |
Table 1: A Comparison of Wind Speeds between F-Scale and EF-Scale Ratings (Adapted for Environment Canada)
The analysis of the Canada Day tornado revealed that one of the destroyed homes was considered “well-built.” This factor contributed to the storm’s strength, which resulted in wind speeds of approximately 275 km/h.
The extent of damage observed at the affected property further demonstrated the tornado’s immense power, as stated by the NTP. Notably, various farm equipment, including a combine weighing nearly 10,000 kilograms, was flipped and thrown, traveling a distance of at least 50 meters before rolling an additional 50-100 meters. Wind tunnel studies on a different combine hit by a previous tornado in Canada suggested a wind speed of 230 km/h was sufficient to cause the flipping of such equipment.
The experts noted that this tornado ranked among the rare few F/EF4 tornadoes ever recorded in Alberta, and it was the strongest since the F4 tornado that struck near Edmonton 35 years ago. The 1987 tornado resulted in the tragic loss of 27 lives, over 300 injuries, and the destruction of 300 homes.
Fortunately, the Canada Day tornado did not cause extensive damage or result in significant injuries. According to the NTP, only one person, a first responder, sustained a minor injury.
The organization has classified a total of 21 tornadoes in Canada as “violent,” categorized as F/EF4 or higher. The country’s sole F5 tornado occurred in Elie, Manitoba, in June 2007.
For further details and additional photographs of the scene, please refer to the online source.