The Difference
Between Flash Floods and Floods
SulCom Summer Weather Program
Flash Floods
A FLASH FLOOD is an event that occurs WITHIN 6 hours following the END of the causative event (such as rains, ice jams, or dam breaks) which result in fatalities, injuries, and/or significant damage to property.  Examples of Flash Floods include damage to buildings, roads, gravel shoulders, bridges, railways or other landscape features including soil erosion.
Generally, flash flooding events develop rapidly and can occur anywhere water collects, especially areas of steep terrain, and water runoffs.  Flash Floods rarely last more than 12 hours.
Floods
A FLOOD is an event that occurs AFTER 6 hours following the END of the causative event (rains, ice jam, dam breaks) which result in fatalities, injuries, and/or significant damage to property.  Examples  of Floods include damage to buildings, roads, gravel shoulders, bridges, railways or other landscape features including soil erosion.
Generally, flooding events usually take longer to develop and they usually occur along or near larger rivers.  The duration of flooding events may extend longer than 24 hours, perhaps several days.

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