Which type of weather event produces the greatest number of fatalities?
According to a report by the U.S. Natural Hazard Statistics of the NOAA National Weather Service, which provides statistical information on fatalities caused by weather related hazards, the weather event that produces the greatest number of fatalities is heat. On a 30-year period from 1986-2015, an average of 130 people lost their lives as a result of heat; a greater number than all other weather events.
Flood came in second with 81 deaths, followed by tornadoes (70), lightning (78), lightning (48), hurricane (46), and winter (40).
In 2015 alone, though, flood had the greatest number of deaths with 155. That was followed by wind (65), rip currents (56), cold (53), heat (45), tornado (36), winter (28), lightning (27) and hurricane (14).
The full graphic from NOAA is available here: http://www.nws.noaa.gov/om/hazstats.shtml