Hazard Plain Automated baseline

Chatham County, GA

Risk-assessment baseline packet

County FIPS:
13051
Release:
2026-10
Data as of:
2026-09-30
Storm Events data through:
2026-06-30

Hazard Plain is an independent product built from public federal data. It is not a FEMA document and is not reviewed or endorsed by FEMA, GEMA/HS or any other state agency.

Hazard Plain release 2026-10, as of 2026-09-30.

Summary

Plan status as of 2026-09-30: Approved, expires 2031-06-08. Plan: Chatham County (FEMA plan 111619), approved 2026-06-09.

Since the plan was approved on 2026-06-09: no new hazard declaration and 5 NOAA Storm Events records; details under "What changed since your last plan".

Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Hurricane ($189,017,956 a year), Inland Flooding ($41,892,542) and Coastal Flooding ($13,074,596).

The tables that follow are organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B (B1-a to B2-c); each heading says which item its tables support.

Plan clock

Status:
Approved, expires 2031-06-08
Plan:
Chatham County (FEMA plan 111619)
Approved:
2026-06-09
Days to expiry:
1,712

What changed since your last plan (approved 2026-06-09)

New federal declarations:
none
Storm Events records since approval:
5 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 60, SRL 52 (44 CFR 77.2); any definition: 492
Repeat-flood change:
this release sets the baseline count.

Sources: 1, 2, 4, 6 (numbered list at the end)

Plan status for every jurisdiction listed in this county

Source: 1

JurisdictionTypeStatusPlanApprovedExpiresDays to expirynegative = days since expiryNotes
Chatham County (unincorporated area)UnincorporatedApproved, expires 2031-06-08Chatham County (FEMA plan 111619)2026-06-092031-06-081,712
Bloomingdale cityTownApproved, expires 2031-06-08Chatham County (FEMA plan 111619)2026-06-092031-06-081,712this jurisdiction approved 2026-07-14
Garden City cityCityApproved, expires 2031-06-08Chatham County (FEMA plan 111619)2026-06-092031-06-081,712
Pooler cityCityApproved, expires 2031-06-08Chatham County (FEMA plan 111619)2026-06-092031-06-081,712
Port Wentworth cityCityApproved, expires 2031-06-08Chatham County (FEMA plan 111619)2026-06-092031-06-081,712
Savannah cityCityApproved, expires 2031-06-08Chatham County (FEMA plan 111619)2026-06-092031-06-081,712
Thunderbolt townTownApproved, expires 2031-06-08Chatham County (FEMA plan 111619)2026-06-092031-06-081,712this jurisdiction approved 2026-07-14
Tybee Island cityCityApproved, expires 2031-06-08Chatham County (FEMA plan 111619)2026-06-092031-06-081,712
Vernonburg townTownApproved, expires 2031-06-08Chatham County (FEMA plan 111619)2026-06-092031-06-081,712this jurisdiction approved 2026-07-14

State plan status and tribal plans in this state: see the state page.

Supports FEMA checklist item B1-a: hazard identification GEMA template A: Hazard identification

Hazards NRI does not cover (local data needed)

  • dam failure (incl. upstream dams)
  • levee failure
  • flash flood as its own subtype
  • ice jams
  • debris flows
  • erosion (riverine and coastal)
  • land subsidence and sinkholes
  • expansive soils

The 18 National Risk Index hazards, ranked by expected annual loss (EAL)

Sources: 5, 6

Rank by EALHazardNRI risk ratingEAL ratingEAL buildingsmodeled dollars per yearEAL agriculturemodeled dollars per yearCost of expected deaths and injuriesFEMA's dollar value per year, not property damageEAL total (see note)modeled dollars per yearStorm Events records, 1996 to 2026-06-30countStorm Events coverage note
1HurricaneVery HighVery High$176,345,604$243,429$12,428,923$189,017,95627Includes 2 Tropical Depression records (outside NRI's Hurricane definition).
2Inland FloodingRelatively ModerateRelatively Moderate$41,489,569$102,014$300,960$41,892,54297
3Coastal FloodingVery HighVery High$10,939,919n/a$2,134,675$13,074,59628
4EarthquakeRelatively ModerateRelatively Moderate$7,989,870n/a$4,471,658$12,461,529Storm Events does not record earthquakes.
5Heat WaveRelatively ModerateRelatively Moderate$406$42$6,390,585$6,391,03314
6Cold WaveRelatively ModerateRelatively Moderate$26,800$7,737$3,551,392$3,585,9305Includes 2 Frost/Freeze records (outside NRI's Cold Wave definition; counted in this table and in B1-d, not in the B1-e descriptor).
7TornadoRelatively ModerateRelatively Moderate$1,644,114$181$1,778,325$3,422,62014
8WildfireRelatively ModerateRelatively Moderate$1,837,206$178$185,434$2,022,8180No recorded events in Storm Events since 1996 (data through 2026-06-30).
9LightningRelatively HighRelatively High$234,366n/a$1,721,034$1,955,40048
10Strong WindRelatively ModerateRelatively Moderate$100,783$56$1,223,207$1,324,046541Includes 8 High Wind and 18 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
11Ice StormRelatively HighRelatively High$810,811n/a$80,549$891,3611
12HailRelatively LowRelatively Low$222,175$92$310,179$532,445148
13Winter WeatherRelatively ModerateRelatively Moderate$54,158$6$65,771$119,9354
14DroughtRelatively LowRelatively Lown/a$54,056n/a$54,05623
15LandslideVery LowVery Low$101n/aunder $1$1020No recorded events in Storm Events since 1996 (data through 2026-06-30).
TsunamiInsufficient DataInsufficient Datan/an/an/an/a0No recorded events in Storm Events since 1996 (data through 2026-06-30).

Total = buildings + agriculture + population equivalence; FEMA values each expected death (or 10 injuries) at $13.7 million (2024 dollars).

NRI risk rating combines expected annual loss with social vulnerability and community resilience; EAL rating rates expected annual loss alone. Both compare this county with all U.S. counties.

Local data needed: state and local wildfire, landslide and tsunami records (Storm Events records these hazards only in part).

Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: avalanche and volcanic activity. That is the evidence for leaving them out of the plan.

The state hazard mitigation plan also lists hazards for this county; FEMA asks the plan to explain any hazard it leaves out.

Supports FEMA checklist item B1-b: hazard location GEMA template B: Hazard profile (events and probability)

Affects the whole county (national data give no location within it): Cold Wave, Drought, Hail, Heat Wave, Ice Storm, Lightning, Strong Wind and Winter Weather.

Coastal Flooding and Inland Flooding: The FEMA Flood Insurance Rate Map (FIRM) is the required location source for flooding. See the FEMA Flood Map Service Center (https://msc.fema.gov) for this county.

Hazards that vary within the county: highest-rated census tracts

Source: 5

HazardHighest-rated census tractsNRI risk rating, score 0 to 100
Earthquaketract 107.01 (Relatively High, 92.6); tract 119 (Relatively High, 90.9); tract 117 (Relatively High, 89.3)
Hurricanetract 107.01 (Very High, 100.0); tract 108.11 (Very High, 100.0); tract 40.02 (Very High, 99.9)
Landslidetract 107.01 (Very Low, 68.4); tract 111.07 (Very Low, 64.7); tract 111.10 (Very Low, 60.4)
Tornadotract 107.01 (Relatively Moderate, 70.8); tract 108.11 (Relatively Moderate, 61.6); tract 40.02 (Relatively Moderate, 57.7)
Tsunamino tract has a National Risk Index rating for this hazard
Wildfiretract 110.05 (Relatively High, 97.6); tract 110.06 (Relatively Moderate, 95.5); tract 42.12 (Relatively Moderate, 95.0)

Up to 3 census tracts per hazard, highest National Risk Index rating first, then highest score; a tract number is the Census tract number (for example 107.01 is Census Tract 107.01). FEMA's Resilience Analysis and Planning Tool maps the National Risk Index for every tract: https://www.fema.gov/emergency-managers/practitioners/resilience-analysis-and-planning-tool

Supports FEMA checklist item B1-c: hazard extent GEMA template B: Hazard profile (events and probability)

Extent: scale, observed range and worst recorded event per hazard

Sources: 6, 7

HazardScaleRecordscount and yearsObserved rangeWorst recorded eventMost damaging (when different)How it applies to jurisdictionsNote
Coastal Flood, Storm Surge/Tidenone in data (flood depth: FIRM)28 records, 2007 to 2025 (28 zone-level)Storm Surge/Tide, 2017-09-11, $5,000,000 property; $0 crops (2017 dollars); NWS zone GAZ119Countywide (zone-level records).Flood depth: see the FEMA Flood Insurance Rate Map.
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill3 records, 1996 to 2026 (3 zone-level)2 days to 3 days (median 2.5 days); 2 with a recorded value3 consecutive days, 1996-02-03 to 1996-02-05, zone-levelCountywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage2 records, 2007 to 2022 (2 zone-level)No crop damage reported in 2 records.Countywide (zone-level records).
DroughtU.S. Drought Monitor scale (D0 to D4)23 records, 1996 to 2002 (23 zone-level)31 days to 365 days (median 84 days); 5 with a recorded value365 days (12 months), 2001-10-01 to 2002-09-30, a run of 12 consecutive Storm Events drought records, zone-levelCountywide (zone-level records).Storm Events enters a drought at D2 or worse east of the Rockies and D3 or worse from the Rockies west (NWS Instruction 10-1605); NRI drought counts D3 and D4 only.
EarthquakeModified Mercalli (local data)0Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hailhail size (inches)183 records, 1957 to 20250.75 in to 3.5 in (median 1 in); 183 with a recorded value3.5 in hail, 1993-04-05Hail, 1993-04-05, $500,000 property; crops not recorded (1993 dollars)Event records naming jurisdictions in the plan: Savannah city (38 records), Thunderbolt town (14 records), Port Wentworth city (12 records), Pooler city (10 records), Bloomingdale city (8 records), Vernonburg town (5 records), Garden City city (1 record).
Excessive Heat, Heatheat index (in event narratives)14 records, 1996 to 2011 (14 zone-level)1 day to 31 days (median 2 days); 10 with a recorded valueAugust 1999 (1 monthly summary record), zone-levelCountywide (zone-level records).
Hurricane, Tropical Storm, Tropical DepressionSaffir-Simpson27 records, 1996 to 2024 (27 zone-level)Strongest recorded: Hurricane record (NOAA event type 'Hurricane (Typhoon)'), 2016-10-08, category 1, damage not reported, 1 direct injury (reported for the zone); NWS zone GAZ119Most damaging recorded: Tropical Storm, 2017-09-11, $5,000,000 property; $0 crops (zone total, 2017 dollars)Countywide (zone-level records).Storm Events files every zone of a storm's episode under the storm's type; flooding from the storm is filed as Flood or Flash Flood records.
Ice StormSperry-Piltz ice scale (local data)1 record, 2014 (1 zone-level)No damage reported in 1 record.Countywide (zone-level records).
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)97 records, 1996 to 2026Flash Flood, 1999-06-29, $7,000,000 property; crops not reported (1999 dollars)Event records naming jurisdictions in the plan: Savannah city (41 records), Vernonburg town (8 records), Pooler city (5 records), Garden City city (4 records), Thunderbolt town (2 records), Bloomingdale city (1 record), Port Wentworth city (1 record).Flood depth: see the FEMA Flood Insurance Rate Map. Storm Events damage is often $0 or blank for floods, major ones included; FEMA Public Assistance by declaration (B1-d) shows which floods cost the most.
Debris Flownone (count and damage only)0
Lightningannualized frequency (the measure FEMA's Local Mitigation Planning Handbook names)48 records, 1996 to 2025Lightning, 2021-06-12, damage not reported, 1 direct death, 1 direct injuryLightning, 2019-08-24, $2,000,000 property; crops not reported (2019 dollars)Event records naming jurisdictions in the plan: Savannah city (11 records), Pooler city (4 records), Thunderbolt town (2 records), Vernonburg town (1 record).Storm Events lists lightning with damage or casualties.
High Wind and Strong Wind (outside NRI's Strong Wind definition)wind speed (kt and mph)26 records, 2004 to 2026 (26 zone-level)30 kt (35 mph) to 55 kt (63 mph) (median 43 kt (49 mph)); 26 with a recorded value55 kt (63 mph) estimated gust, High Wind, 2008-10-24; NWS zone GAZ119Strong Wind, 2024-01-09, $10,000 property; $0 crops (zone total, 2024 dollars)Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)617 records, 1960 to 202639 kt (45 mph) to 110 kt (127 mph) (median 50 kt (58 mph)); 542 with a recorded value110 kt (127 mph), measurement type not recorded, Thunderstorm Wind, 1980-09-08Thunderstorm Wind, 1998-09-03, $1,250,000 property; crops not reported (1998 dollars)Event records naming jurisdictions in the plan: Savannah city (101 records), Bloomingdale city (32 records), Vernonburg town (31 records), Pooler city (25 records), Thunderbolt town (24 records), Port Wentworth city (21 records), Garden City city (17 records).Speeds under 20 kt (likely entry errors) are left out of the observed range.
TornadoEnhanced Fujita (Fujita before Feb 2007)32 records, 1955 to 2019F/EF0 to F/EF2 (median F/EF1); 31 with a recorded valueF2 tornado, 1980-05-23, 1 mi path length (whole path, pre-1996), 100 yd wide, $250,000 property; crops not recorded (1980 dollars), 2 direct injuriesTornado, 2008-06-19, $3,100,000 property; $0 crops (2008 dollars)Event records naming jurisdictions in the plan: Thunderbolt town (3 records), Savannah city (2 records), Bloomingdale city (1 record), Garden City city (1 record).Before 1996 a tornado is listed once, under the county where it began, with its whole path's rating and length; from 1996 on, each county lists its own segment. Length is not used to rank tornadoes (see Methods).
Tsunaminone (count and damage only)0
Wildfireacres burned (local data)0
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)4 records, 2010 to 2026 (4 zone-level)No damage reported in 4 records.Countywide (zone-level records).

In event narratives only (local data needed): wind chill, temperature, heat index, ice thickness, acres burned and snow depth; any physical measure of debris flow, lightning and tsunami.

Storm Events records are more complete after 1996; before 1996 only Tornado (from 1950), Hail and Thunderstorm Wind (from 1955) exist. Zone-level records from zones that no NWS zone-county file places in this county (mostly before 2020) are not counted here (the Methods page explains the zone matching).

Dollars are nominal (as reported), labeled with the year; not adjusted for inflation.

A monthly summary record covers most or all of a month; it does not count days at wave conditions.

Supports FEMA checklist item B1-d: previous occurrences GEMA template B: Hazard profile (events and probability)

Federal declarations for this county: 19 declarations covering 12 separate hazard incidents counted in this packet (declarations for the same incident count once; non-natural and evacuation-only declarations are not counted).

Federal disaster declarations for this county

Sources: 1, 2, 3

DeclaredIncident beganFEMA numberTypeTitleMapped hazardCounty Public Assistancefederal share obligated, nominal dollarsFlagsNotes
2024-09-302024-09-24DR-4830-GAMajor disasterHurricane HeleneHurricane$15,002,866.85within last 5 years
2024-09-262024-09-24EM-3616-GAEmergencyHurricane HeleneHurricaneno Public Assistance recordedwithin last 5 yearssame incident as DR-4830
2024-09-242024-08-04DR-4821-GAMajor disasterTropical Storm DebbyHurricane$3,247,198.27within last 5 years
2024-08-052024-08-04EM-3607-GAEmergencyHurricane DebbyHurricaneno Public Assistance recordedwithin last 5 yearssame incident as DR-4821
2020-03-292020-01-20DR-4501-GAMajor disasterCOVID-19 PandemicNon-natural, not counted$3,955,892.74
2020-03-132020-01-20EM-3464-GAEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedsame incident as DR-4501
2019-09-012019-08-29EM-3422-GAEmergencyHurricane DorianHurricaneno Public Assistance recorded
2018-10-102018-10-09EM-3406-GAEmergencyHurricane MichaelHurricaneno Public Assistance recorded
2017-09-152017-09-07DR-4338-GAMajor disasterHurricane IrmaHurricane$6,010,081.02
2017-09-082017-09-07EM-3387-GAEmergencyHurricane IrmaHurricaneno Public Assistance recordedsame incident as DR-4338
2016-10-082016-10-04DR-4284-GAMajor disasterHurricane MatthewHurricane$45,520,791.79
2016-10-062016-10-04EM-3379-GAEmergencyHurricane MatthewHurricaneno Public Assistance recordedsame incident as DR-4284
2005-09-052005-08-27EM-3218-GAEmergencyHurricane Katrina EvacuationHurricane: evacuation support, not a local hazard event; not counted$25,791.22
1999-09-141999-09-14EM-3144-GAEmergencyHurricane Floyd Emergency DeclarationsHurricane$1,868,429.17
1998-03-111998-02-14DR-1209-GAMajor disasterSevere Storms and FloodingInland FloodingPA not declared for this county
1994-10-191994-10-01DR-1042-GAMajor disasterHeavy Rains, Tornados, Flooding, High WindsInland Flooding; Strong Wind; Tornadono Public Assistance recorded
1993-03-151993-03-13EM-3097-GAEmergencySevere Snowfall, Winter StormWinter Weatherno Public Assistance recorded
1977-07-201977-07-20EM-3044-GAEmergencyDroughtDroughtno Public Assistance recorded
1977-06-021977-06-02DR-536-GAMajor disasterShrimp Loss Due to Cold WeatherCold WavePA not declared for this county

County Public Assistance: applicants the FEMA record places in this county, including any state agencies FEMA files there; statewide rows are listed on the state page; federal share obligated, nominal dollars.

Statewide declarations

Source: 2

DeclaredIncident beganFEMA numberTypeTitleMapped hazard
1964-11-041964-11-04DR-180-GAMajor disasterFloodingInland Flooding
1964-09-101964-09-10DR-177-GAMajor disasterHurricane DoraHurricane (primary); also designated: Inland Flooding
1963-03-261963-03-26DR-150-GAMajor disasterSevere Storms & FloodingInland Flooding
1961-03-021961-03-02DR-110-GAMajor disasterFloodsInland Flooding
1954-03-171954-03-17DR-16-GAMajor disasterTornadoTornado
1953-05-021953-05-02DR-1-GAMajor disasterTornadoTornado

FEMA recorded these with designated area Statewide and no county, so they are listed on every county page in the state and not counted with county rows. Local data needed: whether each one affected this county.

Previous occurrences by hazard, with explicit no-event rows

Sources: 2, 6, 7

HazardStorm Events records, all years on file(years in the Period column)Since plan approvalrecordsIn the 12 months before plan approvalrecordsLast 5 yearsrecordsDeclared incidents, all yearsseparate disastersDeclared since approvalseparate disastersPeriodStatement
Coastal Flooding28023001996 to 2026-06-30
Cold Wave5023101996 to 2026-06-30Includes 2 Frost/Freeze records.
Drought23000101996 to 2026-06-30
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail1830014001955 to 2026-06-30
Heat Wave14000001996 to 2026-06-30
Hurricane27004701996 to 2026-06-30Includes 2 Tropical Depression records.
Ice Storm1000001996 to 2026-06-30
Inland Flooding9702630201996 to 2026-06-30
Landslide0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Lightning48028001996 to 2026-06-30
Strong Wind64352199101955 to 2026-06-30Includes 8 High Wind and 18 Strong Wind records.
Tornado32000101950 to 2026-06-30
Tsunami0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Wildfire0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Winter Weather4012101996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationWhy listed
2021-06-12Lightningdamage not reported1, 1SAVANNAH BEACHdeaths or injuries recorded
2017-09-11Storm Surge/Tide$5,000,000 property; $0 crops (zone total, 2017 dollars)0, 0NWS zone GAZ119 (COASTAL CHATHAM), zone-levelB1-c worst recorded: Coastal Flood, Storm Surge/Tide
2016-10-08Hurricane (NOAA event type 'Hurricane (Typhoon)')category 1damage not reported0, 1NWS zone GAZ119 (COASTAL CHATHAM), zone-levelB1-c worst recorded: Hurricane, Tropical Storm, Tropical Depression
2008-10-24High Wind55 kt (63 mph) estimated gust$8,000 property; $0 crops (zone total, 2008 dollars)0, 0NWS zone GAZ119 (COASTAL CHATHAM), zone-levelB1-c worst recorded: High Wind and Strong Wind
2005-05-17Thunderstorm Wind45 kt (52 mph) estimated gustdamage not reported1, 1SAVANNAHdeaths or injuries recorded
2001-06-25Lightningdamage not reported1, 1SAVANNAHdeaths or injuries recorded
1999-08-01Heatdamage not reported0, 0NWS zone GAZ119 (COASTAL CHATHAM), zone-levelB1-c worst recorded: Excessive Heat, Heat
1999-06-29Flash Flood$7,000,000 property; crops not reported (1999 dollars)0, 0EAST PORTIONB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
1996-02-03Cold/Wind Chilldamage not reported0, 0NWS zone GAZ118 (INLAND CHATHAM), zone-levelB1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
1993-04-05Hail3.5 indamage not recorded (pre-1996 record)0, 0SavannahB1-c worst recorded: Hail
1980-09-08Thunderstorm Wind110 kt (127 mph), measurement type not recordeddamage not recorded (pre-1996 record)0, 0location not recordedB1-c worst recorded: Thunderstorm Wind
1980-05-23TornadoF2, 1 mi path length (whole path, pre-1996), 100 yd wide$250,000 property; crops not recorded (1980 dollars)0, 2location not recordedB1-c worst recorded: Tornado

The full list is in the Excel file, sheet "B1-d Storm Events history" (1,105 rows).

Location is the place NOAA recorded, as written in its data; it need not be a jurisdiction in this plan.

Local data needed: state-declared emergencies, from your state emergency management agency (federal data do not include them).

Tribal and special-area declarations in this state are listed on the state page.

Supports FEMA checklist item B1-e: probability of future events GEMA template B: Hazard profile (events and probability)

Probability: FEMA annualized frequency and descriptor per hazard

Sources: 5, 6

HazardFEMA annualized frequency (modeled)unit per rowUnitIn plain termsDescriptorDescriptor basisNRI events or days in its record period (hail, wind and tornado are area-weighted, so can be fractional)NRI periodLocationNote
Coastal Flooding3.67events per year at a location (modeled)about 3.7 per year at a given location in the countyHighly likelyFEMA annualized frequency (modeled)not shownmodeledsee B1-fDescriptor from NRI: the rate at a location is 1 or more a year, so the county rate is at least that.
Cold Wave0.606event-days per yearabout 0.606 days per yearPossibleStorm Events event-days in 1 of 30 years, 1996 to 2025 (3.33%)9.332005-11-12 to 2024-11-12 (19 years)countywide
Drought18.3event-days per yearabout 18.3 days per yearLikelyStorm Events event-days in 5 of 30 years, 1996 to 2025 (16.7%)6512000 to 2025 (25.25 years; D3 and D4 only)countywide
Earthquake0.00245annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 0.245%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail1.71events per yearabout 1.71 per yearHighly likelyFEMA annualized frequency (modeled)73.5 (modeled)1986 to 2023 (38 years)countywide
Heat Wave9.53event-days per yearabout 9.53 days per yearLikelyStorm Events event-days in 8 of 30 years, 1996 to 2025 (26.7%)1282005-11-12 to 2024-11-12 (19 years)countywide
Hurricane0.349events per yearabout 1 in 3 yearsLikelyFEMA annualized frequency (modeled)1201851 to 2024 (Atlantic)see B1-fNRI counts hurricane and tropical storm tracks passing within storm-force wind range; federal declarations are in B1-d.
Ice Storm0.483event-days per yearabout 0.483 days per yearPossibleStorm Events event-days in 1 of 30 years, 1996 to 2025 (3.33%)271946-12-31 to 2014-02-12 (67 years)countywide
Inland Flooding1.29event-days per yearabout 1.29 days per yearLikelyStorm Events event-days in 20 of 30 years, 1996 to 2025 (66.7%)361996 to 2023 (28 years)see B1-f
Landslide0.0666events per year (modeled)about 1 in 15 yearsPossibleFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning64.9days per year with a strikeabout 64.9 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind1.12events per yearabout 1.12 per yearHighly likelyFEMA annualized frequency (modeled)361986 to 2023 (38 years)countywide
Tornado0.187events per yearabout 1 in 5 yearsLikelyFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Tsunamiannual probability at the most exposed location (used in place of a county value)Storm Events records in 0 of 30 years, 1996 to 2025 (0%)not shownmodeledsee B1-fNo descriptor: no Storm Events record 1996 to 2025
Wildfire0.00209annual probability at a locationchance a given location in the county burns in a year: 0.209%Storm Events records in 0 of 30 years, 1996 to 2025 (0%)not shownmodeledsee B1-fNo descriptor: no Storm Events record 1996 to 2025
Winter Weather0.609event-days per yearabout 0.609 days per yearLikelyStorm Events event-days in 3 of 30 years, 1996 to 2025 (10%)9.292005-11-12 to 2024-11-12 (19 years)countywide

FEMA annualized frequency (modeled) is the National Risk Index v1.20 (December 2025) estimate of how often a hazard affects this county in a year; it is not recorded events divided by years, and its unit differs by hazard (events, event-days, or days with a lightning strike per year). For earthquake, wildfire, coastal flooding and tsunami the value is the chance (or number of events) at a location in the county, not across the county, so no "1 in N years" is given and the descriptor comes from Storm Events where it has a record (none for earthquake). The Methods page gives each hazard's method, from FEMA's National Risk Index Technical Documentation v1.20.

Where NRI gives event-days, the descriptor comes from the share of years with a Storm Events record; NRI's source records more events, so the two differ.

Descriptor scale used in this packet (defined per unit)

Sources: 5, 6

UnitDescriptorDefinition
events per yearHighly likely1 or more per year
events per yearLikelyabout once in 1 to 10 years
events per yearPossibleabout once in 10 to 100 years
events per yearUnlikelyless than once in 100 years
annual probabilityLikely10% to under 100% chance in a given year
annual probabilityPossible1% to under 10% chance in a given year
annual probabilityUnlikelyunder 1% chance in a given year
event-days (share of years)Highly likelyevent-days recorded in 90% or more of years
event-days (share of years)Likelyevent-days recorded in 10% to under 90% of years
event-days (share of years)Possibleevent-days recorded in some years but under 10% of years
lightning strike-daysHighly likelycloud-to-ground strikes on 1 or more days per year

Intensity bands: historical frequency (Storm Events)

Source: 6

HazardBandYearsEventscounty-coded recordsYears in periodEvents per yearevents / years
Hail1.00-1.99 in1996 to 202587302.9
Hail2.00 in+1996 to 20252300.0667
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 20254543015.1
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 202513300.433
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 202541301.37
TornadoEF0-11996 to 202512300.4
TornadoEF2-31996 to 20251300.0333
TornadoEF4-51996 to 20250300
Tornadounrated (EFU)1996 to 20251300.0333

The bands show how often events of each severity were recorded in this county, to profile how severe events have been (FEMA's probability item asks for the range of intensities).

Hail smaller than 1 inch is not counted: on 2010-01-05 the National Weather Service raised its severe-hail threshold from 3/4 inch to 1 inch, so smaller reports became less common after 2009 (NWS Service Change Notice 09-52). NRI hail frequency uses a 0.75 inch threshold.

Optional: future conditions. Not a required item in the 2025 FEMA Local Mitigation Planning Policy Guide; some states ask for it. The federal Climate Mapping for Resilience and Adaptation (CMRA) site gives county exposure to future climate conditions (https://resilience.climate.gov/).

Supports FEMA checklist item B1-f: hazards that vary across jurisdictions GEMA template F: Multi-jurisdictional differences

Range of census tract risk within the county

Source: 5

HazardTractsrated of allNRI risk score, 0 to 100Tracts by rating
MinMedianMax
Coastal Flooding79 of 8769.890.799.8Very High 6, Relatively High 18, Relatively Moderate 19, Relatively Low 28, Very Low 8, No Rating 8
Cold Wave87 of 8716.141.267.1Relatively Moderate 33, Relatively Low 53, Very Low 1
Drought2 of 8790.391.392.3Relatively Moderate 1, Relatively Low 1, No Rating 85
Earthquake87 of 8735.170.792.6Relatively High 3, Relatively Moderate 19, Relatively Low 61, Very Low 4
Hail87 of 8729.044.371.9Relatively Moderate 1, Relatively Low 69, Very Low 17
Heat Wave87 of 871.666.689.5Relatively High 6, Relatively Moderate 63, Relatively Low 17, Very Low 1
Hurricane87 of 8791.096.9100.0Very High 40, Relatively High 47
Ice Storm87 of 8734.162.096.0Relatively High 3, Relatively Moderate 28, Relatively Low 56
Inland Flooding87 of 872.020.898.4Very High 1, Relatively High 6, Relatively Moderate 15, Relatively Low 34, Very Low 31
Landslide57 of 879.832.768.4Very Low 57, No Rating 30
Lightning87 of 8716.865.294.0Relatively High 23, Relatively Moderate 54, Relatively Low 8, Very Low 2
Strong Wind87 of 8710.543.771.4Relatively Moderate 24, Relatively Low 62, Very Low 1
Tornado87 of 8724.837.870.8Relatively Moderate 7, Relatively Low 76, Very Low 4
Tsunami0 of 87Insufficient Data 87
Wildfire83 of 8719.276.997.6Relatively High 1, Relatively Moderate 22, Relatively Low 28, Very Low 32, No Rating 4
Winter Weather87 of 8721.932.772.3Relatively Moderate 10, Relatively Low 77

Drought: Agriculture is all of NRI's expected annual loss for this hazard in the county, so the tract range mostly reflects where crop and livestock value is.

Rated tracts only: No Rating (score 0.0), Not Applicable and Insufficient Data tracts are counted but not used for the minimum, median and maximum.

The score ranks a tract against all U.S. tracts (100 = highest). The rating is FEMA's category for the tract's risk value, computed differently, so the two can disagree.

Frequency data for cold wave, drought, hail, heat wave, ice storm, lightning, strong wind and winter weather are county-wide or coarse (49 km grid or NWS zone), the same for every jurisdiction; the tract range mostly reflects where buildings and people are (crop and livestock value where a line above names agriculture).

Each jurisdiction (starting figures from federal data)

Sources: 1, 3, 4, 6

JurisdictionTypePlan statusRepetitive lossFMA RL and SRL (44 CFR 77.2); repeat-flood, any definitionPublic Assistance to this jurisdictionFEMA records matched by applicant name; federal share obligated, nominal dollarsEvent records naming this placeall years; since its planNotes
Chatham County (unincorporated area)UnincorporatedApproved, expires 2031-06-08FMA RL 14, SRL 6; any 127$37,300,528.780 total; 0 since its planIncludes $25,791.22 for declarations not counted as hazard incidents (EM-3218-GA).
Bloomingdale cityTownApproved, expires 2031-06-08FMA RL 0, SRL 0; any 0$271,366.9142 total; 0 since its plan
Garden City cityCityApproved, expires 2031-06-08FMA RL 0, SRL 0; any 10no Public Assistance recorded23 total; 0 since its plan
Pooler cityCityApproved, expires 2031-06-08FMA RL 1, SRL 1; any 7$928,999.0144 total; 0 since its plan
Port Wentworth cityCityApproved, expires 2031-06-08FMA RL 0, SRL 1; any 5$1,011,425.1634 total; 0 since its plan
Savannah cityCityApproved, expires 2031-06-08FMA RL 24, SRL 39; any 240$21,708,560.52193 total; 2 since its planIncludes $627,209.24 for declarations not counted as hazard incidents (DR-4501-GA).
Thunderbolt townTownApproved, expires 2031-06-08FMA RL 1, SRL 0; any 3$684,703.3345 total; 0 since its plan
Tybee Island cityCityApproved, expires 2031-06-08FMA RL 20, SRL 5; any 99$2,571,335.580 total; 0 since its plan
Vernonburg townTownApproved, expires 2031-06-08FMA RL 0, SRL 0; any 1no Public Assistance recorded45 total; 0 since its plan

Repetitive-loss counts are for whole NFIP communities, which can extend beyond this county (see the note in B2-c).

County Public Assistance in B1-d also includes applicants filed under the county that are not jurisdictions in this plan (for example state agencies, special districts and nonprofits), so the jurisdiction rows add up to less.

Supports FEMA checklist items B2-a and B2-b: vulnerability and potential impacts GEMA template C/D: Community exposure; Estimate of potential losses

Local data needed

The table below gives county-level starting figures; the plan describes impacts for each jurisdiction and its own assets.

County-level starter: exposure, expected annual loss and damage since the plan

Sources: 1, 2, 3, 5, 6, 7

HazardBuilding exposuremodeled dollarsAgriculture exposuremodeled dollarsPopulation exposedpeopleEAL buildingsmodeled dollars per yearEAL agriculturemodeled dollars per yearCost of expected deaths and injuriesFEMA's dollar value per year, not property damageEAL as % of exposurebuildings; agriculture where notedStorm Events damage since 2026-06-09county-coded records, property plus crops, nominal dollarsZone-level damage since planproperty plus crops, reported for the zonePublic Assistance since plannominal dollars; see noteNote
Coastal Flooding$18,236,709,488n/a81,345$10,939,919n/a$2,134,6750.06%
Cold Wave$63,247,040,652$15,739,175293,520$26,800$7,737$3,551,392under 0.0001%
Droughtn/a$14,674,231n/an/a$54,056n/a0.368% (agriculture)NRI has no building exposure for this hazard; agriculture shown
Earthquake$112,754,278,820n/a295,291$7,989,870n/a$4,471,6580.00709%
Hail$63,247,040,652$15,739,175293,520$222,175$92$310,1790.000351%
Heat Wave$63,247,040,652$15,739,175293,520$406$42$6,390,585under 0.0001%
Hurricane$63,246,499,128$15,739,175293,518$176,345,604$243,429$12,428,9230.279%
Ice Storm$63,239,677,992n/a293,457$810,811n/a$80,5490.00128%
Inland Flooding$63,183,695,646$6,625,23941,015$41,489,569$102,014$300,960n/a (see note)NRI counts the full building value of any census block with some flood loss; this is not the value of buildings in the floodplain. Use local FIRM overlays for B2-a/B2-b.
Landslide$33,386,361n/a163$101n/aunder $10.000304%
Lightning$63,247,040,652n/a293,520$234,366n/a$1,721,0340.000371%
Strong Wind$63,247,040,652$15,739,175293,520$100,783$56$1,223,2070.000159%$5,500
Tornado$63,247,040,652$15,739,175293,520$1,644,114$181$1,778,3250.0026%
Tsunamin/an/an/an/an/an/aNRI publishes no building exposure for this county
Wildfire$9,912,272,023$9,572,82261,385$1,837,206$178$185,4340.0185%
Winter Weather$63,247,040,652$15,739,175293,520$54,158$6$65,771under 0.0001%

Totals since 2026-06-09 (Storm Events through 2026-06-30): 5 county-coded records, 4 with a damage value recorded (including $0), $5,500; 0 zone-level records, 0 with a damage value recorded (including $0), $0 reported for the zone; Public Assistance: no counted declaration since the plan.

FEMA does not split Public Assistance by hazard. A declaration mapped to several hazards is listed under each of them with its full amount, so the per-hazard column does not add up to the total; the unit total counts each declaration once.

NRI computes earthquake exposure on its own basis, so it exceeds the county building value in B2-a.

Supports FEMA checklist item B2-a: vulnerability (county context) GEMA template I: Social vulnerability

County context

Source: 5

MeasureValue
Population293,520
Building value (total, not at risk)$63,247,040,652
Agriculture value (total, not at risk)$15,739,175
NRI risk rating (all hazards)Relatively High
Expected annual loss, buildings and agriculture, all hazards$242,103,674
Expected annual loss, population equivalence, all hazards (NRI values each statistical life at $13.7M; a modeled value of expected deaths and injuries, not property damage)$34,642,692
Social vulnerability ratingRelatively Moderate
Community resilience ratingVery High
NRI versionDecember 2025

FEMA's all-hazard expected annual loss adds buildings, agriculture and population equivalence; this table gives the property part and the population-equivalence part as separate rows.

Social vulnerability: higher means people are more likely to be harmed and slower to recover. Community resilience: lower means the community is less able to recover. High social vulnerability and low resilience both raise the NRI risk rating.

Supports FEMA checklist item B2-c: repetitive loss properties

Repetitive loss in this county, both definitions

Sources: 1, 4

DefinitionPropertiesSevere repetitive lossProperties
Repetitive loss, FMA definition (44 CFR 77.2)60Severe repetitive loss, FMA definition (44 CFR 77.2)52
Repetitive loss, NFIP insurance definition448Severe repetitive loss, NFIP insurance definition19

The state NFIP coordinator's list, the source FEMA's Handbook names, often uses the NFIP insurance definition (second row).

Repeat-flood properties: county and state-level rows

Sources: 1, 4

ScopeRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
County total60524481949217222
of which: Chatham County (unincorporated area)1461255127171
of which: Pooler city1171703
of which: Thunderbolt town1030302
of which: Garden City city0010010010
of which: Port Wentworth city0151500
of which: Savannah city243920182401462
of which: Tybee Island city20596499273
of which: Vernonburg town0010101
Statewide, no county in FEMA's file2252616

The statewide row counts properties FEMA's file gives with no county in this state; they are listed for reference and are not in this county's counts.

Repeat-flood properties by jurisdiction in the plan (NFIP community)

Sources: 1, 4

JurisdictionNFIP community IDRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
Chatham County (unincorporated area)1300301461255127171
Bloomingdale city1304520000000
Garden City city1351610010010010
Pooler city1302611171703
Port Wentworth city1351620151500
Savannah city135163243920182401462
Thunderbolt town1304601030302
Tybee Island city13516420596499273
Vernonburg town1351650010101

Counts by occupancy group for each jurisdiction are in the Excel file, sheet "B2-c Jurisdictions".

Jurisdiction rows are whole NFIP communities and need not add up to the county total: a community that extends into another county is counted in full on each jurisdiction row, while the county table counts only its part in this county.

County repeat-flood properties by occupancy group

Sources: 1, 4

Occupancy groupRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
single-family residential57494021744516205
2 to 4 unit residential101601606
other residential1251614
non-residential112512507
not reported0000000

FEMA's occupancy groups have no institutional class; institutional properties are counted in non-residential or other residential in the table by occupancy group.

FMA RL and FMA SRL are the Flood Mitigation Assistance definitions (44 CFR 77.2), the ones the FEMA Local Mitigation Planning Policy Guide cites. NFIP repetitive loss (the FEMA insurance definition) is 2 or more claims over $1,000 in 10 years, and a property can leave that group once it is mitigated. Also shown: NFIP severe repetitive loss, any category, mitigated and currently insured. The Methods page gives the OpenFEMA field details.

Counts are aggregates of FEMA's public NFIP Multiple Loss Properties file (FEMA's data date 2026-08-02; file version 2026-08-04). No property is identified. County assignment is FEMA's geocode.

In this county 22 properties are FMA repetitive loss but not NFIP repetitive loss, and 410 properties are NFIP repetitive loss but not FMA repetitive loss.

Exact counts; no count suppression.

Sources

Tables cite these sources by number. The full list, for the plan's bibliography (FEMA review item A4-a):

  1. FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-29T134039Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
  2. FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-29T162832Z, pulled 2026-09-30, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
  3. FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-29T150754Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
  4. FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
  5. FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-30, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
  6. NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-30, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
  7. NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-30, https://www.weather.gov/gis/ZoneCounty
  8. U.S. Census Bureau, Census 2024 Gazetteer, 2020 place by county, CT county-to-cousub crosswalk, version 2024-gazetteer, pulled 2026-09-30, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_counties_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_cousubs_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_place_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_unsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_elsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_scsd_national.zip, https://www2.census.gov/geo/docs/reference/codes2020/national_place_by_county2020.txt, https://www2.census.gov/geo/docs/reference/ct_change/ct_cou_to_cousub_crosswalk.xlsx (used to match place names and codes; no table prints its values)

GEMA local plan template

Section headings show the GEMA local hazard mitigation plan template letter (A to I) next to the FEMA checklist item (template: https://gema.georgia.gov/document/publication/local-hazard-mitigation-plan-update-template/download). No letter is documented for repetitive loss; place B2-c where your GEMA template puts it.

What this packet is and what the plan adds

This packet is the federal data for the plan's risk assessment (the summary on page 1 says how it is organized); the plan and FEMA's review decide whether each item is met.

The plan adds what only the community has: local data on assets, critical facilities, development and each jurisdiction's impacts; local hazard history, including state-declared emergencies; the mitigation strategy; and adoption.

How the federal data are built: National Risk Index values are FEMA's model, not counts of events. Storm Events is more complete from 1996; zone-level records are placed by forecast zone, not by location in the county. Public Assistance for a jurisdiction is matched by applicant name. The Methods page gives every rule and the known edge cases.

OpenFEMA disclaimer

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

Reuse, citation and corrections

Reuse and citation: Hazard Plain text and tables are licensed under Creative Commons Attribution 4.0 International (CC BY 4.0, https://creativecommons.org/licenses/by/4.0/); credit Hazard Plain and the release. The underlying federal data are public domain; OpenFEMA data are also subject to the OpenFEMA terms and conditions.

Cite this: Hazard Plain (2026). Chatham County, GA: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 13051). Automated baseline. https://hazardplain.org/ga/13051/ Built from FEMA OpenFEMA, the FEMA National Risk Index and NOAA NCEI Storm Events; source versions in the packet's Sources list.

Corrections: to report an error, name the packet, the table and what your records show. Contact: [email protected]