document: Here are some tornado facts from the National Weather Service , Insurance Information Institute and news accounts : _ Tornadoes can occur in any month , but are more frequent from April through June and between 3 and 6 p.m. _ Most tornadoes track southwest to northeast , but their paths can spiral erratically . _ The portion of a thunderstorm adjacent to large hail is where tornadoes are most likely to occur . _ There were 32 tornado-related deaths reported in 1988 , down from 59 in 1987 and well below the average of 99 a year . _ Less than 2 percent of all tornadoes are classified as violent , with wind speeds of more than 200 mph and a path averaging 26 miles . The longest tornado on record went 219 miles across Missouri , Illinois and Indiana in March 1925 . _ Tornadoes travel at an average 30 mph , but can stand still or go 70 mph . _ The largest single outbreak of twisters on record was in April 1974 , when 148 storms killed 300 people in 13 states over two days . _ When a tornado threatens , seek shelter in the basement or central parts of the house , office or school building , away from windows .
extractive_keyphrases: tornadoes tornado facts thunderstorm
abstractive_keyphrases: tornado-related deaths