Glossary of Flood Terms | Flood Zone Definitions | Availability

Flood Terminology:

First American Flood Data Services: A leader in the field of flood zone determinations, works with some of the nation's largest originators and mortgage services to offer the most accurate certifications in the industry. We offer flexible delivery systems to help you locate a property, its boundaries, and determine the status of the insurable improvements.

First American Flood Data Services digital flood map database delivers one of the highest-quality, most accurate, up-to-date and comprehensive flood map databases commercially available anywhere. If you are responsible for risk assessment, flood hazard determination, disaster response and recovery planning, environmental impact planning, or site selection—First American Flood Data Services is for you!
 
The Federal Emergency Management Agency (FEMA) provides no digital maintenance for the 12,000 map revisions it issues annually-but FloodMap does! FloodMap reflects all FEMA revisions. The entire database is refreshed quarterly to ensure accuracy, currency and investment value. When we process your order, you’ll receive the most recent digital flood map information available. To keep your database current, select the optional subscription service and FloodMap will provide quarterly updates for your data set.
 
The FloodMap database is meticulously verified with each effective Federal Insurance Rate Map (FIRM) panel for visual content and completeness, accurate polygon shape matching and labeling. The data includes both the 100-year Flood Zones (the national standard for flood insurance) and 500-year Flood Zones. The result: Flood hazard data you can trust.

100-year flood: The flood having a 1% or greater annual probability of occurring.

500-year flood: The flood having a 0.2% or greater annual probability of occurring.

Base Flood: Defined by FEMA as the flood having a 1-percent probability of being equaled or exceeded in any given year; also referred to as the 100-year flood.

Base Flood Elevation (BFE): Defined by FEMA as the height of the base (100-year) flood in relation to a specified datum, usually the National Geodetic Vertical Datum of 1929 or North American Vertical Datum of 1988. Generally speaking, this is the elevation of the 100-year flood waters relative to "mean sea level". BFE is not depth of flooding. To determine depth of flooding, you would need to subtract the lowest elevation of a particular property from the BFE. For example, if the property's foundation was at an elevation of 125 feet and the BFE was 131 feet, then one might infer that the 100-year depth of flooding would be approximately 6 feet.