Southern Ontario Tornadoes of 1996

Southern Ontario's worst tornado outbreak of the decade came on April 20th, 1996. Severe weather had raked parts of the US Midwest the day before (especially in Illinois, where an F3 tornado touched down near Galva). A cold front was being dragged eastward into unusually warm and unstable air associated with a strong storm system moving through the northern tier of the US. Out of the two tornadoes that day, which were both rated F3, it was remarkable that nobody died.

9 people escaped with only some minor injuries, however many homes were severely damaged in Williamsford, Arthur, and Violet Hill. Many areas that experienced the tornadoes on May 31, 1985 were hit once again, especially the Grand Valley area. The first tornado that touched down tore a 40km long path southeast of Owen Sound. The second tornado touched down further south and had a 60km path that tracked from Arthur to just southwest of Barrie.

=Grey County tornado=

Ahead of the main cold front, a separate storm formed into a supercell southwest of Williamsford, and was likely triggered by the aging squall line farther west. Then, at about 5:50pm, a funnel cloud touched down about 5km southwest of Williamsford. Only sporadic tree damage took place at this point. The storm was high based, and there was a large gap between the tornado and the core of the storm which was consistent through much of the tornado’s life. The wall cloud was large and showed clear signs of rotation.

As the tornado passed through town, it was large and messy, and then divided into multiple vortices shortly after. The collective width of the damage path was about 1300ft wide, and extensive debris filled the air. At Williamsford, it did extensive F3 damage to a strip of homes along Chatsworth Road 24 (a township concession road). It then crossed Williams Lake, damaging some cottages and ripping up trees. As it crossed the small lake, it became a waterspout for a brief time, and some of the multi-vortices became visible. The tornado continued to move northeast, and as it neared Holland Centre, the tornado hurled a 2000 gallon gasoline tank (weighing at about 2 tons) for more than a mile (over 1.6 kilometers). At this point, the tornado crossed Highway 10. As the tornado neared the town of Walters Falls, it became more compact, but didn’t weaken at all. Damage was continuous, but concentrated (consisting mainly of tree damage). East of Walters Falls, the tornado became very strange in appearance as the funnel split into two separate vortices. A debris cloud persisted under both of these funnels, as they rotated around each other. The tornado then rolled through the town of Blantyre where some homes suffered F2 damage.Shortly after this the tornado began to weaken, and finally lifted just before 6:30pm. The parent storm then moved out over the icy waters of Georgian Bay near Meaford, where it rapidly dissipated.

=Wellington County tornado=

This storm initially formed northwest of London around 5pm and slowly moved northeast where it began to began to produce funnel clouds. The first touchdown was about 8km southwest of Arthur at 6:10pm. A small funnel cloud was visible, but there was mostly just a large mass of dust at the ground. Within the next few minutes, the tornado then began to take on a tube-like form. It was a multiple-vortex tornado, with as many as 4 distinct vortices inside the main path. The tornado’s overall width was about 1500ft. It went quickly from F1-F2 and widened, then became an F3 as it approached town from the southwest.

Extensive damage began on the west side of Arthur shortly after. As the tornado passed by Highway 6, it was at its peak strength. The tornado had a separate companion for a brief time, a thin black appendage that swept around the front of the main circulation. As the main tornado crossed the highway, it destroyed a barn full of hay, which tinted the tornado yellow for a brief time. The tornado’s parent supercell also became more intense. A torrent of rain and hail preceded the tornado around the north side of the path. The mesocyclone was rather large, even pulling some of the precipitation ahead of the storm. As the storm moved farther northeast, it nearly destroyed several farms before it plowed into the Luther Marsh, north of Grand Valley. East of the marsh, the storm weakened somewhat, and the tornado narrowed in width.

Upper level winds were stretching out the storm, and causing a larger gap between the precipitation core and the tornado, thus making it even more visible to people in the path of the storm. On the northern end of the tornado’s path, there was a mixture of torrential rain and large hail. South of the tornado, it was warm and windy, with no precipitation falling, and with a spectacular view of the tornado. It damaged more homes, and then crossed Highway 25, taking down several hydro transformers in one very bright power flash. The tornado now had a textbook-style appearance as a narrow wedge. F2 damage continued on as the tornado approached the town of Shelburne, in Dufferin County. Pieces of sheet metal and wood fell from the sky and littered the southern end of town after they were thrown out of the tornado. It then damaged more homes and buildings as it ripped across the southeast end of town. The tornado stayed at around F2-F3 intensity as it moved out of Shelburne, into more open country. The path was now about 500 feet wide. It then moved toward the suburban town of Violet Hill, where several more homes sustained F2-F3 damage.

Not long after, the tornado then began to enter the final stages of its life as the path narrowed to 150ft. Then, outflow from the core of the storm undercut the mesocyclone, and then the tornado finally lifted just after 7pm.

Rarity

Some consider these tornadoes to be quite a rare occurrence, both for its date, and location (as this part of Ontario is quite hilly and high in elevation, nicknamed the "Roof of Ontario").

Never before have such intense, long tracked tornadoes occurred this early in the season in Canada. At the time, there was still snow on the ground in some areas and Lake Huron was still covered in ice, since April 1996 was unseasonably cold. Light snows also fell after the event in the areas hardest hit by the tornadoes, which hampered the clean-up efforts.

References

#Verkaik, Arjen & Jerrine. Under The Whirlwind. Whirlwind Books, 1997.
#Verkaik, Arjen. The Severe Weather Watcher Handbook. Environment Canada, 2000.

ee also

* April 1996 Tornado Outbreak Sequence