Microbursts - powerlul downdrafts generally associated with thunderstoms that occur in hot, humid weather - have caused a number of aircraft crashes. To prevent future accidents, air traffic controllers mustbe able to detect, and predict, microburst events. All microbursts are not alike, however; several distinct weather patterns can produce microbursts. Thus a categorization ofthe different types of microbufsts is an essential part of understanding these hazardous phenomena. Using this categorization, the relative hazardtoaviation of the various types ofmicrobursts can be assessed.