Description: Five different zones can be found throughout Yolo County. • Zone A is the flood insurance rate zone that corresponds to the 100-year floodplains that are determined in the Flood Insurance Study. No Base Flood Elevations or depths are available within the zone. Mandatory Flood Insurance purchase requirements apply. • Zone AE Is the flood insurance rate zone that corresponds to 100-year floodplains that are determined in the Flood Insurance Study by detailed methods. In most places, Base Flood Elevations are available. Flood Insurance purchase requirements apply. • Zone AO is the flood insurance rate zone that corresponds to the 100-year floodplains that are determined in the Flood Insurance Study. Flood depths of 1 to 3 feet (usually sheet flow on sloping terrain) are available within the zone. • Zone X is a flood insurance rate zone that correspond to areas outside the 100-year floodplains. No Base Flood Elevations or depth are shown in this zone. • Zone D is areas in which Flood Hazards are undetermined, but possible.