Environment Canada has issued a tornado warning for the Ottawa-Gatineau area.

A dangerous thunderstorm moving east could possibly produce a tornado.

In the case of a tornado, people should:

Head indoors to a room on the lowest floor, like a basement, bathroom, stairwell or closet.

Stay away from outside walls and windows.

Leave mobile homes, vehicles, tents, trailers and other temporary or free-standing shelters, and move to a strong building if you can.

As a last resort, lie in a low spot and protect your head from flying debris.

A tornado watch is also in place for other communities in eastern Ontario, including Cornwall, Brockville, Pembroke, Smiths Falls and Gananoque.

A thunderstorm warning is also in place for Ottawa.

The severe thunderstorm threat should end by early Friday evening, Environment Canada says.