TORONTO - Environment Canada has determined a tornado that touched down during a weekend thunderstorm near Sarnia, Ont., was an F-2 twister.

That's in the middle range of the Fujita scale that rates tornadoes from zero to five.

Meteorologist Randy Mawson says Saturday's tornado in east Lambton County packed winds of 200 to 230 kilometres an hour.

Environment Canada says damage from the storm was caused by a combination of a tornado and a downburst.

The strong winds damaged as many as five steel transmission towers and 20 wooden poles. Power was knocked out to as many as 13,000 customers at one point.

No injuries were reported.