what is flood zone moderate
In a High-Risk area, there is at least a 1 in 3 chance of flooding during a 20 year period. Changing weather patterns, erosion and new development will affect floodplain boundaries. What are the categories of a Flood Zone? HIGH RISK FLOOD ZONE â Probability of flooding is greater than or equal to 1 in 20 years. MODERATE RISK FLOOD ZONE â Probability of flooding is less than 1 in 30 years. LOW RISK FLOOD ZONE - Probability of flooding is less than 1 in 100 years.