Main Page | See live article | Alphabetical index A tornado warning is issued when: a tornado is reported on the ground, a funnel cloud is reported in the sky, a waterspout is headed toward landfall, or a thunderstorm with strong rotation is indicated by doppler radar. A tornado warning means there is IMMEDIATE DANGER for the warned area -- if not from the relatively narrow tornado itself, from the severe thunderstorm producing (or likely to produce) it. EVERYONE in the path of such a storm should TAKE COVER IMMEDIATELY, as it is likely a LIFE-THREATENING SITUATION. In the United States, the National Weather Service issues warnings for tornados and severe thunderstorms on a per-county basis. A warning must not be confused with a tornado watch. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.