A tornado ripped through Teviotdale, Ont., tearing the roof off a home and extensively damaging another as widespread storm systems thundered across much of southern Ontario in waves Sunday and left nearly 50,000 without power, which has mostly been restored.

Environment Canada has confirmed an EF-2 tornado touched down after an investigator was sent to the area. The Enhanced Fujita Scale rates tornadoes from "light" to "incredible" and this one was considered "moderate," which includes winds ranging between 138 to 177 km/h.

The tornado touched down around 9 p.m. ET Sunday as violent storms battered the region, according to Peter Kimbell, a meteorologist with Environment Canada. 

Two homes In Teviotdale were "significantly damaged from a possible tornado," the weather agency said. Downed trees and power lines were also reported in the area.

The area is 54 kilometres northwest of Guelph, where a turbulent storm system made its way across the region and knocked out electricity for thousands of Ontarians. Kimbell said an investigator was in the area to look for a clear damage path, eyewitnesses and any video of the storm that may exist. 

Environment Canada issued a release describing the storm as "one of the most significant severe weather outbreaks of the summer ... when several rounds of violent thunderstorms crossed southern Ontario."

The weather agency said the tornado was caused by very warm, humid conditions combined with strong upper level winds along with a looming cold front.

The storms came in waves after coming ashore from Lake Huron and making its way southeast toward Lake Ontario.

Tornadoes have been ruled out in other areas of the province that faced the storm.

Peak wind gusts were estimated to reach 110 km/h in Grand Bend at 8 p.m. Sunday, and 104 kilometres at 12:32 p.m. in Cove Island near Tobermory. Wiarton received 78 millimetres of rain. All three sites are close to Lake Huron.

In Toronto, gusts were 90 km/h, with 94 km/h winds at Pearson airport, 96 km/h in Uxbridge and 89 km/h in Oshawa.

There was also notable damage in the Uxbridge area, specifically Port Perry, where several trees were down.

Environment Canada said its findings do not constitute a complete or final report.