Tornado at peak strength at 5:32 PM.
|Date||September 11, 2023|
|Touchdown location||5:23 PM CDT|
185 mph (estimated)
|Damage||$800 million (2023 USD)|
|Areas affected||Steinbach, Manitoba area|
| Part of the|
2023 Tornado Season
Touching down at 5:23 PM CDT, the tornado left a path 16.60 miles in length and attained a peak width of over half a mile, but was significantly narrower while at EF4 strength. The tornado remained on the ground for 36 minutes and reached a peak intensity of mid-range EF4, with estimated wind speeds of 185 miles per hour, to the northeast of Steinbach. Due to the highly rural nature of the areas impacted by the tornado, few casualties occurred, with only one fatality and seven injuries being reported. The tornado was the first to be rated EF4 or higher on the Enhanced Fujita scale in Canada, as well as the first violent tornado in the country since the 2007 Elie, Manitoba F5, and the first violent tornado in the month of September ever recorded in Canada.
The tornado was extensively photographed and captured on video by local residents and storm chasers along virtually all of its path, making it one of the most well-documented tornadoes in history. An Environment Canada-funded storm chasing team also successfully deployed research pods into the tornado allowing for detailed recordings of its internal structure to be taken. One storm chaser was injured by debris from the tornado while deploying a research pod, but made a full recovery; though the incident, coupled with the deaths of two storm chasers in a derecho in North Dakota on August 23 led to considerable questioning over the safety of storm chasing as a practice.
Conditions over southern Manitoba on September 11 were noted as being similar to June 22, 2007, which produced the first tornado to be rated F5 in Canadian history. In the morning hours into the afternoon, a low-pressure system moved over Manitoba from Saskatchewan, with a warm front established to the north of Winnipeg and a trailing cold front across Lake Manitoba. Atmospheric instability in the area was in the realm of 2,900 J/kg, which, coupled with the presence of ample directional and speed shear, supported the development of supercells across much of the southern third of the province.
Nine tornadoes were confirmed in Manitoba during the afternoon hours; all except for the Steinbach tornado were weak and short-lived. An EF1 tornado caused considerable roofing damage to frame houses and partially demolished several mobile homes in the town of Winkler at around 3:30 pm CDT, injuring six people. An additional six tornadoes occurred in northern Minnesota on the same day, including an EF2-rated tornado which caused damage to over 200 houses in Karlstad at 4:52 pm CDT. 19 people were injured by this tornado, although no fatalities occurred.
The supercell that produced the Steinbach tornado developed shortly after 3:00 pm CDT near the small agricultural town of Carman. The supercell gradually intensified as it tracked slowly northeast; by 3:45 pm, wind gusts of at least 105 kilometres per hour (65 mph) prompted the issuance of a severe thunderstorm warning for the Rural Municipality of Morris. At around 4:10 pm, hail up to 8 centimetres (3 inches) in diameter began to fall near the town of Rosenort, injuring at least one person. A short-lived funnel cloud was also reported near Rosenort, but no tornado warning was issued for the intensifying supercell at the time. As the storm continued over rural areas, several storm chasers moved into position to monitor its development; these storm chasers would later deploy research pods into the Steinbach tornado and compile particularly detailed information on the internal structure of the storm. By 5:15 pm, a visible hook echo developed within the core of the supercell, and a tornado warning was issued for the Rural Municipalities of Hanover, La Broqueire, and Ste. Anne. A brief tornado was observed at 5:22 pm, which lasted for only a few seconds and caused no reported damage.
The Steinbach tornado touched down at 5:23 pm CDT as a narrow rope-shaped funnel to the west-northwest of Steinbach. Shortly after touching down, the tornado toppled several power poles and snapped tree branches at low-end EF1 strength. As the tornado moved east at roughly 40 kilometres per hour (25 mph), two frame houses had their roofing stripped and a row of oak trees was toppled before the tornado moved over empty fields, widening into a tall stovepipe while simultaneously intensifying explosively. Two houses around 2 kilometres (1.24 miles) to the northwest of Steinbach were partially demolished at 5:27 pm at high-end EF2 strength. Three people were injured at this location, and one woman was killed. Moments later, the tornado had reached EF3 strength, tossing a parked tractor-trailer 95 yards from a highway. The driver had left the truck and taken shelter in a nearby culvert, and survived the tornado with only minor injuries. Several trees at the side of the highway were snapped and uprooted before the tornado struck a cluster of rural houses while continuing to rapidly intensify. Several of the houses were completely demolished or entirely leveled, while numerous others sustained moderate to severe damage. Two people in this cluster of homes were critically injured, but both survived.
By the time the tornado passed directly to the north of Steinbach just after 5:30 pm, it had attained EF4 strength. Three farmhouses to the north of the city were leveled, with debris pushed off of the foundation and deposited in a pile in one case, while several barns were cleanly swept away. Several tractors in the area were thrown in excess of 130 yards, while a minivan was tossed 175 yards and a pickup truck was thrown 140 yards. After crossing through a series of empty fields, the tornado impacted a larger rural brick house at peak strength. The house was completely leveled with most of the foundation swept clean of debris. An Environment Canada damage survey noted that the house was "very well-anchored". The damage at this property, coupled with mostly-debarked trees in the vicinity led to a rating of mid-range EF4 for the tornado, with estimated peak winds of 300 kilometres per hour (185 mph). Low-end EF4 damage continued for an additional three kilometres to the east of Steinbach, with several more rural houses being flattened and numerous trees being debarked.
At 5:40 pm, the tornado weakened to EF3 strength while simultaneously becoming large and wedge-shaped. A vehicle manufacturing plant sustained severe damage with two exterior walls being blown down and car parts being scattered nearly 800 metres (874 yards) away from the site. The tornado then crossed a stretch of uncultivated meadows before striking a row of mobile homes while still at EF3 strength. At least 15 mobile homes were completely leveled and four people were injured, although no fatalities occurred in the area. The tornado reached a peak width of just under 890 metres (0.55 miles) at 5:47 pm as it approached the town of Richer.
As the tornado passed to the west of Richer, it weakened to EF2 strength, removing the roofs from three rural houses and demolishing a tractor shed. Passing over another stretch of fields, the tornado tipped over a hay baler before crossing a rural road and snapping several power poles. Another house in this area had its roof completely removed, a parked car in its driveway flipped, and two nearby elm trees snapped. The tornado then continued over rural meadows, with the final instance of structural damage being to the west-northwest of Richer, where a well-constructed frame house had its roofing completely removed.
The tornado crossed through a forested area for the final half-mile of its path, continuing to weaken while again taking the shape of a tall and narrow stovepipe. Damage surveys found tree branches snapped with several trees being pushed over or uprooted, and assigned a rating of EF0 to low-end EF1 towards the end of the tornado's path. Storm chasers noted that the tornado's forward speed rapidly accelerated in the last few seconds of its life; likely nearing 80 kilometres per hour (50 miles per hour). The tornado dissipated to the north of Richer at 5:59 pm; remaining on the ground for 36 minutes over a 16.60 mile path.
Casualties and impact
The Steinbach tornado remained over rural areas for most of its life and caused relatively few causalties. One woman was killed in the destruction of her home, and an additional seven people were injured; four were hospitalized. A four-year-old boy suffered life-threatening injuries, but recovered. In addition to human casualties, several cattle and four horses were killed, with several others being injured. Environment Canada reports state that the tornado caused $4.8 million in damage, but unofficial statements by local newspapers report $5.1 million in damage.
The tornado reached peak strength to the north-northeast of Steinbach, leveling a well-constructed rural frame house and sweeping a portion of the slab foundation clean of debris. Environment Canada damage surveys estimated wind speeds at this location to have been approximately 300 kilometres per hour (185 miles per hour) and assigned a final rating of mid-range EF4. The tornado was the first officially-rated violent tornado in Canada since an F5 tornado struck Elie, Manitoba on June 22, 2007, as well as the first in Canada to be rated EF4 or higher on the Enhanced Fujita Scale.
Ground pods deployed into the tornado by storm chasers allowed for advanced analysis of the tornado's internal structure, including examination of the formation and dissipation of suction vortices in unprecedented detail.