An avulsion is the process by which flow is diverted out of an established channel into a new course on the adjacent floodplain. Occurrences of avulsions are what makes an alluvial fans “active.” Avulsions give the alluvial fan the ability to distribute water and sediment over the surface of the landform, which results in a radial “fan” shape. Avulsions influence flood hazards on an alluvial fan landform by changing the location, concentration and severity of flooding on the fan surface. Avulsions have been observed on several alluvial fans in central and western Arizona. The avulsion history of several fan evaluation sites are documented and described. It is likely that there are other examples of major avulsions in Arizona, but no comprehensive evaluation of avulsion frequency or occurrences has been made. Historical records clearly indicate that avulsions do occur on the types of alluvial fans found in central and western Arizona. The cursory data summarized above indicate that it is likely that avulsions are relatively rare events, and that they are often associated with the occurrence of large floods. However, further documentation of the avulsion history of local alluvial fans is warranted to better assess the recurrence interval and frequency of avulsions. Almost all of the known causative factors for avulsions exist on alluvial fans in central and western Arizona, and thus it is likely that avulsions will continue to occur in the future.