The storm in Wellington County initially formed northwest of London around 5:00pm and slowly moved northeast where it began to produce funnel clouds. The first touchdown was about 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 began to take on a tube-like form. It was a multiple-vortex tornado, with as many as four distinct vortices inside the main path. The tornado's overall width was about . It went quickly from F1 to F2 and widened, then became an F3 as it approached town from the southwest.