weather warning

Definition: A weather warning from Environment Canada means severe weather is occurring or is highly probable. Weather warnings may be issued from six to twelve hours in advance. Severe thunderstorm or tornado warnings are sometimes issued as little as one hour or less in advance. Weather warnings may be issued for thunderstorms, tornados, freezing rain, frost, wind, duststorm, blizzards, heavy snowfall, winter storms, wind chill, or cold waves.