A sudden inundation is a sudden and unexpected flooding of an area. It can be caused by a number of different events, such as a SPATE, AVALANCHE, or FRESHET. A SPATE is a sudden and violent rush of water, often caused by heavy rain or melting snow. An AVALANCHE is a large mass of snow, ice, and rocks that suddenly slides down a mountain slope. A FRESHET is a sudden flood of a river or stream, usually caused by heavy rains or melting snow. All of these events can cause a sudden inundation, resulting in flooding and destruction.