Flash flood
Topic: Natural Hazards and Disaster Management in India · NCERT: Class 6, Ch 3 "Landforms and Life"; Class 11, Ch 6 "Natural Hazards and Disasters: Causes, Consequences and Management"
Meaning
A flash flood is a sudden flood that lasts only a short time. It comes after very heavy rain, a cloudburst (100 mm or more of rain in one hour over a small area), or the failure of a dam or glacial lake. Water rises within minutes or hours, so people get almost no warning. Flash floods are common in hills and steep valleys, and in dry western India. There the hard, dry ground cannot soak up a sudden downpour. Because they come so fast, flash floods are very deadly, even though they cover small areas.
Example
In 2010, a cloudburst over Leh in Ladakh sent flash floods and debris flows down its slopes. In western India, Rajasthan, Gujarat, Haryana and Punjab also face flash floods.
Don't confuse with
- Riverine flood: in eastern rivers such as the Brahmaputra and Ganga, water rises slowly over a season and stays for weeks. A flash flood rises and falls within hours.