Tornadoes "Severe Weather 101: Tornado FAQ" Tornadoes nssl.noaa.gov NSSL Tornado FAQ 10-20 miles per hour. nssl.noaa.gov nssl.noaa.gov Tornadoes Tornadoes 10-20 miles per hour. 10-20 miles per hour. 10-20 miles per hour. https://www.nssl.noaa.gov/education/svrwx101/tornadoes/faq/ 10-20 miles per hour.