Some of the typical language and terms to know...
It is important to understand the typical vocabulary and key terms associated with flood risk. This page is dedicated to defining key terms used in the flood risk/flood insurance industry.
FEMA - Federal Emergency Management Agency
FEMA is a federal agency that is tasked with defining flood risk throughout the United States. Floodplains are communicated in digital form called Digitial Flood Insurance Rate Maps or DFIRMs. Each community participating in the National Flood Insurance Program (NFIP) has a defined initial DFRIM date. This date is used to compare with the building structure date (when the building/home was constructed). From this comparison, we often define the following terms: Pre and Post FIRM.
- Pre FIRM - Defines a building that was constructed prior to the initial development of a Federal Insurance Rate Map, often before around 1975 for most communities.
- Post FIRM – Defines a building that was constructed after the initial development of a Federal Insurance Rate Map, often after around 1975 for most communities. For example, if your home was built in the year 2005 it would most likely be considered Post FIRM.
NFIP - National Flood Insurance Program
The NFIP is responsible for providing federally backed flood insurance policies and regulations. Within the past 10 years or so, many private flood insurance providers have been established. Check out the following links for more information:
LOMA - Letter of Map Amendment
– or Letter of Map Amendment
is an official document from FEMA that confirms your building structure is outside of the Special Flood Hazard Area (SFHA). These include the High Risk Zone designations defined in the section below.
General Flood Events and Terms
- 100 Year Storm - A storm that on average has a 1% chance of happening in any given year. This does not mean it will only happen once a year. For example, in 2004 there were several “100 year storms” within a few months. In Florida, this event can equate to around 10-14 inches of rain over a 24-hr period.
- 100 Year Floodplain – Often referred to as the Special Flood Hazard Area (SFHA) or the area of land that is expected to be impacted with water after a 100 year storm.
- Base Flood Elevation (BFE) – the elevation of the water associated with the 100 year floodplain. This elevation is established using engineering models. Only High Risk Zones have defined BFEs.
- Note: No Flood Florida will report a BFE value of None for any Moderate Risk or Low Risk Zone.
- BFE Lines – BFE Lines are used to characterize the elevations of riverine or creek systems. Since flowing systems experience resistance (friction) to flow due to debris, vegetation, and stormwater infrastructure, the extent or elevation of the floodplain also changes. Typically, as the creek or river flows downstream, the floodplain elevation or BFE Lines will decrease in magnitude.
FEMA Flood Zones
- High Risk Zones
- Zone A – These areas are similar to the 100 year floodplain, with the exception of not having an engineering model establishing the Base Flood Elevation. Homes in these areas are typically required to purchase flood insurance.
- Zone AE – These areas are subject to inundation by the 100 year storm event. Base Flood Elevations (BFEs) derived from detailed hydraulic analyses are established. Mandatory flood insurance purchase requirements and floodplain management standards apply. No Flood Florida further breaks down the Zone AE floodplains into AE, LEVEL POOL and AE, RIVERINE. An AE, LEVEL POOL flood zone indicates a none-flowing system, while the AE, RIVERINE designation defines flood zones that are associated with flowing systems.
- Zone VE – These areas are subject to inundation by the 100 year storm event with additional hazards due to storm-induced velocity wave action. Base Flood Elevations (BFEs) derived from detailed hydraulic analyses are established. Mandatory flood insurance purchase requirements and floodplain management standards apply.
- Moderate Risk Zones
- Zone X, shaded – These areas are subject to inundation during what is called the 500 year storm. The 500 year storm has a 0.2 % chance of happening in any given year. This happens less often than the 100 year storm. Homes in these areas typically are not required to purchase flood insurance. No Flood Florida defines this zone as X, 0.2 PCT ANNUAL CHANCE FLOOD HAZARD with a BFE of None.
- Low Risk Zones
- Zone X – The areas of minimal flood hazard, which are the areas outside the SFHA and higher than the elevation of the 0.2-percent-annual-chance flood (500 year flood), are labeled Zone C or Zone X (unshaded). No Flood Florida defines this zone as X, AREA OF MINIMAL FLOOD HAZARD with a BFE of None.
Building Structure and Elevation Terms
- Elevation Certificate – An official document completed by a Professional Surveyor that helps you verify a house’s Finished Floor Elevation (FFE). You may want to get this to reduce flood insurance cost if a house is elevated.
- Finished Floor Elevation (FFE) - This is the elevation of the lowest floor of your home. It is typically determined through a survey by a Professional Survey. No Flood Florida uses LiDAR technology to provide FFE approximations for flood insurance estimation purposes.
- Structure Ground Elevation (SGE) - An approximation of the surrounding terrain near the building structure. This is officially defined as the Lowest Adjacent Grade (LAG) and is determined through a survey by a Professional Surveyor. No Flood Florida uses LiDAR technology to provide SGE values and use them for LOMA qualification purposes.
- LiDAR - Light Detection and Ranging - a remote sensing method that uses pulsed light to measure ranges (variable distances) to the Earth. This technology is critical for developing highly accurate Digitial Elevation Models or DEMs of the Earth's surface.
- Vertical Datums - a surface of zero elevation to which heights of various points are referenced. Working with multiple datums is similar to working with various units. For example, one could state the length of piece of paper is 1 foot or 12 inches.
- NGVD29-ft – The Sea Level Datum of 1929 was named the National Geodetic Vertical Datum of 1929 on May 10, 1973. The datum is defined by the observed heights of mean sea level at the 26 tide gauges and by the set of elevations of all bench marks resulting from the adjustment. This vertical datum was replaced by the NAVD88 datum and is not typically seen in floodplain mapping efforts these days.
- NAVD88-ft – The North American Vertical Datum of 1988 (NAVD 88) is the vertical control datum established in 1991 by the minimum-constraint adjustment of the Canadian-Mexican-United States leveling observations. In 1993 NAVD 88 was affirmed as the official vertical datum in the National Spatial Reference System (NSRS). The NAVD88 datum is currently used in elevation studies and floodplain mapping efforts.
General Real Estate Terms
- Mortgage - An agreement between you and a lender (often a bank or other financial institution) that allows you to borrow money purchase or maintain a home, land, or other types of real estate.
- Title Company – An entity that is responsible for verifying that the title to the property is given to the home buyer. The title company also ensures the seller has the right to sell the property. Title companies often provide insurance in the event that someone protests the sale or declares the rights to the property in the future.
- Closing Documents – A variety of documents associated with the purchase/ownership of a home. Some examples are closing disclosure, loan application, mortgage note, title documents, deed, and initial escrow disclosure. Some localities often have additional requirements and documents needed for real estate closing.