A flash flood is a rapid flooding of low lying regions due to one of several causes. It is a short term event which occurs within six hours of the causative incident. It is characterized by a rapid stream rise with depths of water that can reach well above the banks. The main causes of flash floods are:
- Heavy rains or thunderstorms
- Cloudburst
- Snowmelt
- Levee Failure
- Dam break
- Tropical storm
- Human activities such as unplanned construction.
Flash floods can cause widespread damage to person and property. The maximum impact is in areas close to the stream. Heavy rains falling on steep terrain can weaken soil and cause mudslides damaging roads and and property. Following the flood, the amount of run-off also increases, thus increasing the load of the river. The most recent examples of flash floods are the 2013 Uttarakhand flood and the 2014 Jammu and Kashmir flood. Human activities such as mining and dam construction tend to interfere with the fragile ecosystem in several parts of the world. In the case of both the Uttarakhand floods and the Jammu-Kashmir floods, it has been seen that the rush to build tourist resorts and other facilities as well as several dams has made the Himalayan region highly vulnerable to large-scale natural disasters. Therefore, development must be
planned in accordance with the needs of the ecosystem.
