Zone A is a designation for properties that are flood-prone in the event of a 100-year flood, but for which there is insufficient data available to establish a base flood elevation or a flooding depth. Several properties near San Francisquito Creek were mapped on the Flood Insurance Rate Maps as Zone A following the 1998 flood. These properties were subjected to flooding during the 1998 flood even though FEMA's hydrologic models did not predict such flooding.
