Doing some grilling in really cold weather? Be careful when you're turning on your barbecue. The brass valves have stems that can snap if you force them too hard when they're brittle from the extreme cold. When you first turn your barbecue on, start with one burner and one burner only.
Assuming you get it working, put the lid down and let that one burner warm up the entire barbecue for about ten minutes before you try to turn the other valves. If it's really, really cold and the valves won't turn at all - don't force them. Take a hairdryer and an extension cord and blow hot air onto one valve until it loosens up enough to get the barbecue started. A blowtorch will work too but there's also a slight risk of you melting your knobs with a blowtorch.
Hey look, a true griller isn't going to let a little frostbite get in the way of a good meal.