Last week, on June 5, Denver in Colorado was hit by a giant tornado.
This video shows footage of the event as it happened with the huge expanse of sky covered with grey clouds and an intense black swirling formation.
The man who filmed the weather phenomenon unfolding shows the funnel cloud near Vona, east of Denver, then moves the lens around to show another darkening patch of sky where at least one, if not two, more funnels are forming.
According to Weather Underground, a tornado is: "A violently rotating column of air which descends from a thunderstorm to the ground."
Funnel-shaped clouds extend from the cloud base of a thunderstorm and become tornadoes when it is half-way between the cloud and the ground.
Those following the storm reported as many as four separate tornadoes last week in Denver, the Washington Post reported.
The National Weather Service has also just issued a tornado alert for parts of New York, lasting until 10pm tonight local time.
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