Floods have several main types. River flooding occurs when prolonged rain or snowmelt causes rivers to exceed levees. Coastal flooding results from storm surge and storm-driven water level rises. Flash floods from intense rainfall are most dangerous in valleys and low areas.
Urban flooding occurs when asphalt and concrete cannot absorb rainwater, causing building-height water to accumulate in minutes. Subways and underground parking are especially dangerous.
Flood prevention includes engineering and personal preparation. Levees, dams, and embankment reinforcement mitigate river flooding. In cities, drainage system improvements and permeable pavement help. Personally, avoiding flood-prone areas, waterproofing homes, and subscribing to emergency alert systems matter.
Checking historical flood maps to see how frequently specific addresses are affected by flooding is important before buying homes.