From Environment Canada:
Each year lightning kills approximately 10 Canadians and injures approximately 100 to 150 others. So, how do you keep yourself and your family safe when lightning strikes? Read the tips and information below and stay safe!
The first and most important thing to remember is that if you can hear thunder, you are within striking distance of lightning. Take shelter immediately, preferably in a house or all-metal automobile (not convertible top). If caught outside far from a safe shelter, stay away from tall objects, such as trees, poles, wires and fences. Take shelter in a low lying area.
Remember, there is no safe place outdoors during a thunderstorm. Once in a safe location, remain there for 30 minutes after the last rumble of thunder is heard before resuming your outdoor activities.
Visit Environment Canada's Lightning Safety page for more information.