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Definitions of FEMA Flood Zone Designations
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Flood zones are
geographic areas that the FEMA has defined according
to varying levels of flood risk. These zones are
depicted on a community's Flood Insurance Rate Map
(FIRM) or Flood Hazard Boundary Map. Each zone
reflects the severity or type of flooding in the
area. |
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Moderate to Low Risk Areas |
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In
communities that participate in the NFIP, flood
insurance is available to all property owners and
renters in these zones: |
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ZONE |
DESCRIPTION
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B, C, and X
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Areas
outside the 1-percent annual chance
floodplain, areas of 1% annual chance sheet
flow flooding where average depths are less
than 1 foot, areas of 1% annual chance
stream flooding where the contributing
drainage area is less than 1 square mile, or
areas protected from the 1% annual chance
flood by levees. No Base Flood Elevations or
depths are shown within this zone. Insurance
purchase is not required in these zones.
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High
Risk Areas |
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In
communities that participate in the NFIP, mandatory
flood insurance purchase requirements apply to all
of these zones: |
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ZONE |
DESCRIPTION
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A |
Areas
with a 1% annual chance of flooding and a
26% chance of flooding over the life of a
30-year mortgage. Because detailed analyses
are not performed for such areas; no depths
or base flood elevations are shown within
these zones. |
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AE, A1-A30
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Areas
with a 1% annual chance of flooding and a
26% chance of flooding over the life of a
30-year mortgage. In most instances, base
flood elevations derived from detailed
analyses are shown at selected intervals
within these zones. |
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AH |
Areas
with a 1% annual chance of shallow flooding,
usually in the form of a pond, with an
average depth ranging from 1 to 3 feet.
These areas have a 26% chance of flooding
over the life of a 30-year mortgage. Base
flood elevations derived from detailed
analyses are shown at selected intervals
within these zones. |
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AO |
River or
stream flood hazard areas, and areas with a
1% or greater chance of shallow flooding
each year, usually in the form of sheet
flow, with an average depth ranging from 1
to 3 feet. These areas have a 26% chance of
flooding over the life of a 30-year
mortgage. Average flood depths derived from
detailed analyses are shown within these
zones. |
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AR |
Areas
with a temporarily increased flood risk due
to the building or restoration of a flood
control system (such as a levee or a dam).
Mandatory flood insurance purchase
requirements will apply, but rates will not
exceed the rates for unnumbered A zones if
the structure is built or restored in
compliance with Zone AR floodplain
management regulations. |
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A99 |
Areas
with a 1% annual chance of flooding that
will be protected by a Federal flood control
system where construction has reached
specified legal requirements. No depths or
base flood elevations are shown within these
zones. |
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Undetermined Risk Areas |
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ZONE |
DESCRIPTION
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D |
Areas
with possible but undetermined flood
hazards. No flood hazard analysis has been
conducted. Flood insurance rates are
commensurate with the uncertainty of the
flood risk. |
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