Read the text and answer the question. A whirlwind swept over the village of Chigiri in the Amur region. Local residents managed to film the whirlwind's formation on video. The footage, published on social networks, shows a characteristic funnel appearing against a background of a darkening thunderstorm sky. In one of the village yards, a large pool was overturned, and power lines were also damaged. What is the natural phenomenon described in the text called?