Flash flooding

Flash flooding is a rapid and extreme flow of high water into a normally dry area, or a rapid water level rise in a stream or creek above a predetermined flood level, beginning within six hours of the causative event (e.g., intense rainfall, dam failure, ice jam). Unlike regular floods, which can take days to develop, flash floods are known for their sudden onset, often occurring with little to no warning, making them particularly dangerous.

Causes

Flash floods are typically caused by a number of factors, including heavy rainfall, rapid snowmelt, and ice jams. However, intense rainfall is the most common cause. This can be due to thunderstorms, hurricanes, or tropical storms. Urban areas are particularly susceptible to flash flooding due to the large amounts of impermeable surfaces, such as roads and buildings, which prevent water from being absorbed into the ground. This is often referred to as urban flooding.

Effects

The effects of flash flooding can be devastating, leading to loss of life, damage to infrastructure and property, and environmental degradation. Flash floods can sweep away cars, erode foundations, and destroy buildings. They can also lead to longer-term impacts such as water contamination and the displacement of communities.

Prevention and Mitigation

Efforts to prevent or mitigate the effects of flash flooding include the development of flood warning systems, urban planning strategies that incorporate green spaces and permeable surfaces, and the construction of flood barriers and detention basins. Public education on the dangers of flash flooding and how to respond during a flash flood event is also crucial.

See Also

• Flood
• Urban flooding
• Water cycle
• Hydrology