What are the characteristics of a flash flood?

Flooding that begins within 6 hours, and often within 3 hours, of the heavy rainfall (or other cause), is said to be flash flooding. The characteristics of flash floods are as follows:

1. These are mostly caused due to extremely heavy rainfall from thunderstorms
2. Flash Floods can occur due to Dam or Levee Breaks, and/or Mudslides
3. Other factors that contribute to flash flooding are as follows:
   • The intensity of the rainfall
   • Location and distribution of the rainfall
   • Land use and topography
   • Vegetation and soil types

Further Reading: 

• What are Floods?
• Indian Meteorological Department