||What is flash flood||Why is it happened||

 The recent flash flood of Jalpaiguri's Mal river

Flash flood in Mal river is a very common phenomenon. Jalpaiguri in West Bengal, pidmont region of Darjeeling, Alipurduar etc. in the pidmont region of Shivalik Hinalay are alluvial fan lands. Teesta is the main river of this region and one of its tributaries is Mal river. 

1) Darjeeling descended from the Sikkim Himalayas over thousands of yearsRivers have dumped a lot of silt and created huge alluvial fans over a wide area, across which alluvial plains have been born. Today, villages and towns are built on these alluvial fans. But the rivers want to flow along its wings at a rapid pace. 

2. Rivers carry excess water over them during monsoon every year. So the rivers are maintaining their own systems but we are theirsI am standing in the middle of the road. But rivers have maintained or want to maintain this system according to their rules.

3) Mal river originates from Darjeeling Himalayas, the catchment basin of this river is not very wide, so only if there is a short period of heavy rain, the excess water here cannot create a carrying capacity for a short period of time, as a result, the catchment basin of this river is short period of time. Heavy rains occur in a short period of timeThe water will wash and come down to the lower basin causing flash flood or Harpa Ban. A flash flood can occur here due to the heavy rains caused by thick clouds blocking the water vapor filled air at the foot of the Himalayas. 

By Somnath Kumar Das