Hazard Plain Automated baseline

Guam, GU

Risk-assessment baseline packet

County FIPS:
66010
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 or any state agency.

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

Summary

Plan status as of 2026-09-30: Approved, expires 2029-07-24. Plan: Guam state-level plan (plan 109894), approved 2024-07-25.

Since the plan was approved on 2024-07-25: 3 new hazard declarations (2 incidents) and 12 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 ($148,706,410 a year), Tsunami ($39,756,024) and Earthquake ($26,351,829).

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 2029-07-24
Plan:
Guam state-level plan (plan 109894)
Approved:
2024-07-25
Days to expiry:
1,028

Plan clock from the Guam state-level plan; FEMA plan data has no county-level or local plan row for this area.

What changed since your last plan (approved 2024-07-25)

New federal declarations:
3 new hazard declarations (2 incidents): EM-3644-GU (Typhoon Sinlaku), DR-4921-GU (Super Typhoon Sinlaku), EM-3648-GU (Typhoon Bavi)
Storm Events records since approval:
12 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 1, SRL 1 (44 CFR 77.2); any definition: 16
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 expiryUpdate underwayNotes
No rows for this unit.

No jurisdictions listed in FEMA plan data for this unit.

Plan 109894 covers 1 other participant: Guam.

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

Supports FEMA checklist item B1-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 2026-06-30countWhy this hazard can be left outNRI Not Applicable, no declaration and no Storm Events record since 1996Storm Events coverage note
1HurricaneInsufficient DataVery High$140,265,531$6,329$8,434,550$148,706,41031Includes 2 Tropical Depression records (outside NRI's Hurricane definition).
2TsunamiInsufficient DataRelatively High$413,777n/a$39,342,247$39,756,0240No recorded events in Storm Events since 1996 (data through 2026-06-30).
3EarthquakeInsufficient DataRelatively Moderate$20,346,681n/a$6,005,148$26,351,829Storm Events does not record earthquakes.
4Inland FloodingInsufficient DataVery Low$0$800$591,112$591,91187
5Coastal FloodingInsufficient DataRelatively Low$148,211n/a$281$148,4932
6Cold WaveInsufficient DataNo Expected Annual Losses$0$0$0$00No recorded events in Storm Events since 1996 (data through 2026-06-30).
7Heat WaveInsufficient DataNo Expected Annual Losses$0$0$0$00No recorded events in Storm Events since 1996 (data through 2026-06-30).
8Winter WeatherInsufficient DataNo Expected Annual Losses$0$0$0$00No recorded events in Storm Events since 1996 (data through 2026-06-30).
DroughtInsufficient DataInsufficient Datan/an/an/an/a12
HailInsufficient DataInsufficient Datan/an/an/an/a0No recorded events in Storm Events since 1996 (data through 2026-06-30).
LandslideInsufficient DataInsufficient Datan/an/an/an/a1
LightningInsufficient DataInsufficient Datan/an/an/an/a19
Strong WindInsufficient DataInsufficient Datan/an/an/an/a13Includes 10 High Wind and 2 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
TornadoInsufficient DataInsufficient Datan/an/an/an/a0No recorded events in Storm Events since 1996 (data through 2026-06-30).
Volcanic ActivityNot ApplicableNot Applicable4NRI rates this Not Applicable, but 4 Storm Events records of this type exist since 1996; review before omitting.
WildfireInsufficient DataInsufficient Datan/an/an/an/a7

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 tsunami, cold wave, heat wave, winter weather, hail and tornado 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 ice storm. 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

Affects the whole county (national data give no location within it): Cold Wave, Drought, Hail, Heat Wave, 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
Earthquakeno tract has a National Risk Index rating for this hazard
Hurricaneno tract has a National Risk Index rating for this hazard
Landslideno tract has a National Risk Index rating for this hazard
Tornadono tract has a National Risk Index rating for this hazard
Tsunamino tract has a National Risk Index rating for this hazard
Volcanic Activityno tract has a National Risk Index rating for this hazard
Wildfireno tract has a National Risk Index rating for this hazard

Up to 3 census tracts per hazard, highest National Risk Index rating first, then highest score; a tract number is the Census tract number. 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

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)2 records, 2015 to 2024 (2 zone-level)Coastal Flood, 2015-07-11, $1,000,000 property; $0 crops (2015 dollars); Storm Events area GUAM (legacy zone code GUZ006)Countywide (zone-level records).Flood depth: see the FEMA Flood Insurance Rate Map.
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill0
Frost/Freeze (outside NRI's Cold Wave definition)crop damage0
DroughtU.S. Drought Monitor scale (D0 to D4)12 records, 1998 to 2025 (12 zone-level)29 days to 120 days (median 80 days); 4 with a recorded value120 days (4 months), 1998-01-01 to 1998-04-30, a run of 4 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)0
Excessive Heat, Heatheat index (in event narratives)0
Hurricane, Tropical Storm, Tropical DepressionSaffir-Simpson31 records, 1997 to 2026 (30 zone-level)Strongest recorded: Hurricane record (NOAA event type 'Hurricane (Typhoon)'), 2023-05-23 to 2023-05-25, category 4, $4,000,000,000 property; $10,000,000 crops (2023 dollars) (as recorded; larger than this county's annual agriculture value in the National Risk Index (the county or state extension service keeps crop loss records)); Storm Events area GUAM (legacy zone code GUZ006)No event record names a jurisdiction in the plan. Zone-level records (30) apply countywide.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.
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)87 records, 1997 to 2024 (4 zone-level)Flash Flood, 2004-06-27, $5,500,000 property; $500,000 crops (2004 dollars) (as recorded; larger than this county's annual agriculture value in the National Risk Index (the county or state extension service keeps crop loss records)), 1 direct deathNo event record names a jurisdiction in the plan. Zone-level records (4) apply countywide.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)1 record, 2025Debris Flow, 2025-10-15, $15,000 property; $0 crops (2025 dollars)No event record names a jurisdiction in the plan.
Lightningannualized frequency (the measure FEMA's Local Mitigation Planning Handbook names)19 records, 1997 to 2022Lightning, 2011-10-14, $0 property; $0 crops (2011 dollars), 1 direct deathLightning, 1999-02-14, $100,000 property; crops not reported (1999 dollars)No event record names a jurisdiction in the plan.Storm Events lists lightning with damage or casualties.
High Wind and Strong Wind (outside NRI's Strong Wind definition)wind speed (kt and mph)12 records, 1997 to 2025 (12 zone-level)35 kt (40 mph) to 53 kt (61 mph) (median 51 kt (59 mph)); 9 with a recorded value53 kt (61 mph) measured gust, High Wind, 2009-10-15; Storm Events area GUAM (legacy zone code GUZ006)High Wind, 1997-08-12, $300,000 property; $100,000 crops (zone total, 1997 dollars)Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)1 record, 202049 kt (56 mph); 1 with a recorded value49 kt (56 mph) measured gust, Thunderstorm Wind, 2020-11-23No event record names a jurisdiction in the plan.
TornadoEnhanced Fujita (Fujita before Feb 2007)0Before 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
Volcanic Ash, Volcanic AshfallVolcanic Explosivity Index (local data)4 records, 2003 to 2005 (4 zone-level)No damage reported in 4 records.Countywide (zone-level records).
Wildfireacres burned (local data)7 records, 1998 to 2024 (2 zone-level)Wildfire, 1998-03-01, $120,000 property; crops not reported (1998 dollars)No event record names a jurisdiction in the plan. Zone-level records (2) apply countywide.
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)0

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

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.

Supports FEMA checklist item B1-d: previous occurrences

Federal declarations for this county: 22 declarations covering 18 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
2026-07-032026-07-02EM-3648-GUEmergencyTyphoon BaviHurricanenot yet in FEMA's PA summaries (they cover declarations through 2026-06-30)new since last plan; within last 5 years
2026-06-302026-04-11DR-4921-GUMajor disasterSuper Typhoon SinlakuHurricaneno Public Assistance recordednew since last plan; within last 5 years
2026-04-112026-04-11EM-3644-GUEmergencyTyphoon SinlakuHurricaneno Public Assistance recordednew since last plan; within last 5 yearssame incident as DR-4921
2023-10-082023-10-08EM-3601-GUEmergencyTropical Storm BolavenHurricaneno Public Assistance recordedin the 12 months before plan approval; within last 5 years
2023-05-252023-05-22DR-4715-GUMajor disasterTyphoon MawarHurricane$2,045,803.53within last 5 years
2023-05-222023-05-22EM-3594-GUEmergencyTyphoon MawarHurricaneno Public Assistance recordedwithin last 5 yearssame incident as DR-4715
2020-03-272020-01-20DR-4495-GUMajor disasterCOVID-19 PandemicNon-natural, not counted$1,042,789.99
2020-03-132020-01-20EM-3466-GUEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedsame incident as DR-4495
2019-05-072019-02-23DR-4433-GUMajor disasterTyphoon WutipHurricaneno Public Assistance recorded
2018-10-012018-09-10DR-4398-GUMajor disasterTyphoon MangkhutHurricane$53,762.17
2015-06-052015-05-13DR-4224-GUMajor disasterTyphoon DolphinHurricane$12,095.50
2014-09-102014-07-28DR-4191-GUMajor disasterTropical Storm HalongHurricane$38,564.43
2004-07-292004-06-26DR-1533-GUMajor disasterHigh Winds, Flooding, and Mudslides As a Result of Tropical Storm TingtingHurricane; Inland Flooding; Landslide; Strong Wind$0
2002-12-082002-12-08DR-1446-GUMajor disasterSuper Typhoon PongsonaHurricane$321,821.90
2002-07-062002-07-05DR-1426-GUMajor disasterTyphoon Chata'anHurricane$124,097.93
2001-12-052001-10-13DR-1397-GUMajor disasterEarthquakeEarthquake$2,707.05
1997-12-171997-12-16DR-1193-GUMajor disasterTyphoon Paka, Torrential Rains, High Winds, High SurfHurricaneno Public Assistance recorded
1992-08-281992-08-28DR-957-GUMajor disasterTyphoon OmarHurricaneno Public Assistance recorded
1991-12-041991-11-27DR-924-GUMajor disasterTyphoon YuriHurricaneno Public Assistance recorded
1990-12-241990-12-21DR-887-GUMajor disasterTyphoon RussHurricaneno Public Assistance recorded
1988-01-201988-01-11DR-810-GUMajor disasterTyphoon RoyHurricaneno Public Assistance recorded
1976-05-221976-05-22DR-503-GUMajor disasterTyphoon PamelaHurricaneno Public Assistance recorded

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
1963-04-301963-04-30DR-153-GUMajor disasterTyphoon OliveHurricane (primary); also designated: Inland Flooding
1962-11-121962-11-12DR-140-GUMajor disasterTyphoon KarenHurricane (primary); also designated: Inland Flooding

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.

1 Fire Management declaration (1998-03-22 to 1998-03-22) FEMA filed as Statewide with no county; each names one local fire. Listed on the state page.

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 Flooding2011001996 to 2026-06-30
Cold Wave0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Drought12246001996 to 2026-06-30
Earthquake000010Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail0000001955 to 2026-06-30No recorded events, 1955 to 2026-06-30, NOAA NCEI Storm Events
Heat Wave0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Hurricane313151721996 to 2026-06-30Includes 2 Tropical Depression records.
Inland Flooding874314101996 to 2026-06-30
Landslide1101101996 to 2026-06-30
Lightning19001001996 to 2026-06-30
Strong Wind13202101955 to 2026-06-30Includes 10 High Wind and 2 Strong Wind records.
Tornado0000001950 to 2026-06-30No recorded events, 1950 to 2026-06-30, NOAA NCEI Storm Events
Tsunami0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Volcanic Activity4000001996 to 2026-06-30
Wildfire7011001996 to 2026-06-30
Winter Weather0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2025-10-15Debris Flow$15,000 property; $0 crops (2025 dollars)0, 0TAMUNINGnew since last plan; within last 5 yearsB1-c worst recorded: Debris Flow
2023-05-23Hurricane (NOAA event type 'Hurricane (Typhoon)')category 4$4,000,000,000 property; $10,000,000 crops (zone total, 2023 dollars) (as recorded; larger than this county's annual agriculture value in the National Risk Index (the county or state extension service keeps crop loss records))0, 0Storm Events area GUAM (legacy zone code GUZ006), zone-levelwithin last 5 yearsB1-c worst recorded: Hurricane, Tropical Storm, Tropical Depression
2020-11-23Thunderstorm Wind49 kt (56 mph) measured gust$100,000 property; crops not reported (2020 dollars)0, 0ANDERSEN AFB to BARRIGADAB1-c worst recorded: Thunderstorm Wind
2015-07-11Coastal Flood$1,000,000 property; $0 crops (zone total, 2015 dollars)0, 0Storm Events area GUAM (legacy zone code GUZ006), zone-levelB1-c worst recorded: Coastal Flood, Storm Surge/Tide
2011-10-14Lightning$0 property; $0 crops (2011 dollars)1, 0AGANAdeaths or injuries recorded
2009-10-15High Wind53 kt (61 mph) measured gust$0 property; $0 crops (zone total, 2009 dollars)0, 0Storm Events area GUAM (legacy zone code GUZ006), zone-levelB1-c worst recorded: High Wind and Strong Wind
2004-06-27Flash Flood$5,500,000 property; $500,000 crops (2004 dollars) (as recorded; larger than this county's annual agriculture value in the National Risk Index (the county or state extension service keeps crop loss records))1, 0COUNTYWIDEdeaths or injuries recorded
2002-12-08Hurricane (NOAA event type 'Hurricane (Typhoon)')$125,000,000 property; crops not reported (zone total, 2002 dollars)1, 300Storm Events area GUAM (legacy zone code GUZ006), zone-leveldeaths or injuries recorded
1999-02-14Lightning$100,000 property; crops not reported (1999 dollars)0, 0CENTRAL PORTIONB1-c most damaging: Lightning
1998-03-01Wildfire$120,000 property; crops not reported (1998 dollars)0, 0MERIZOB1-c worst recorded: Wildfire
1998-01-01Droughtdamage not reported0, 0Storm Events area GUAM (legacy zone code GUZ006), zone-levelB1-c worst recorded: Drought
1997-08-12High Windspeed not recorded$300,000 property; $100,000 crops (zone total, 1997 dollars)0, 0Storm Events area GUAM (legacy zone code GUZ006), zone-levelB1-c most damaging: High Wind and Strong Wind

The full list is in the Excel file, sheet "B1-d Storm Events history" (176 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).

FEMA's declaration data list no tribal or special-area declarations for this state.

Supports FEMA checklist item B1-e: probability of future events

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 Flooding0.977events per year at a location (modeled)about 0.98 per year at a given location in the countyPossibleStorm Events records in 2 of 30 years, 1996 to 2025 (6.67%)not shownmodeledsee B1-f
Cold Wave0event-days per yearnone modeledStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)02005-11-12 to 2024-11-12 (19 years)countywideNo Storm Events cold wave record, 1996 to 2025.
Droughtevent-days per yearLikelyStorm Events event-days in 4 of 30 years, 1996 to 2025 (13.3%)2000 to 2025 (25.25 years; D3 and D4 only)countywide
Earthquake0.104annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 10.4%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hailevents per year1986 to 2023 (38 years)countywideNRI publishes no annualized frequency for this hazard in this county.
Heat Wave0event-days per yearnone modeledStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)02005-11-12 to 2024-11-12 (19 years)countywideNo Storm Events heat wave record, 1996 to 2025
Hurricane0.368events per yearabout 1 in 3 yearsLikelyFEMA annualized frequency (modeled)281949 to 2024 (Pacific)see B1-fNRI counts hurricane and tropical storm tracks passing within storm-force wind range; federal declarations are in B1-d.
Inland Flooding2.57event-days per yearabout 2.57 days per yearLikelyStorm Events event-days in 15 of 30 years, 1996 to 2025 (50%)721996 to 2023 (28 years)see B1-f
Landslideevents per year (modeled)not shownmodeledsee B1-fNRI publishes no annualized frequency for this hazard in this county.
Lightningdays per year with a strikenot shown1995 to 2023 (29 years; CONUS)countywideDescriptor not assigned: NRI publishes no lightning frequency for this county.
Strong Windevents per year1986 to 2023 (38 years)countywideNRI publishes no annualized frequency for this hazard in this county.
Tornadoevents per yearnot shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-fNRI publishes no annualized frequency for this hazard in this county.
Tsunami0.124annual probability at the most exposed location (used in place of a county value)chance at the county's most exposed location in a year: 12.4%Storm Events records in 0 of 30 years, 1996 to 2025 (0%)not shownmodeledsee B1-fNo descriptor: no Storm Events record 1996 to 2025
Volcanic Activityannual probabilitynot shownmodeledsee B1-fNot Applicable in NRI for this county; no descriptor.
Wildfireannual probability at a locationLikelyStorm Events records in 4 of 30 years, 1996 to 2025 (13.3%)not shownmodeledsee B1-f
Winter Weather0event-days per yearnone modeledStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)02005-11-12 to 2024-11-12 (19 years)countywideNo Storm Events winter weather record, 1996 to 2025

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.

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 20250300
Hail2.00 in+1996 to 20250300
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 20250300
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 20250300
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 20251300.0333
TornadoEF0-11996 to 20250300
TornadoEF2-31996 to 20250300
TornadoEF4-51996 to 20250300
Tornadounrated (EFU)1996 to 20250300

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

Range of census tract risk within the county

Source: 5

HazardTractsrated of allNRI risk score, 0 to 100Tracts by rating
MinMedianMax
Coastal Flooding0 of 56Insufficient Data 56
Cold Wave0 of 56Insufficient Data 56
Drought0 of 56Insufficient Data 56
Earthquake0 of 56Insufficient Data 56
Hail0 of 56Insufficient Data 56
Heat Wave0 of 56Insufficient Data 56
Hurricane0 of 56Insufficient Data 56
Inland Flooding0 of 56Insufficient Data 56
Landslide0 of 56Insufficient Data 56
Lightning0 of 56Insufficient Data 56
Strong Wind0 of 56Insufficient Data 56
Tornado0 of 56Insufficient Data 56
Tsunami0 of 56Not Applicable 29, Insufficient Data 27
Volcanic Activity0 of 56Not Applicable 56
Wildfire0 of 56Insufficient Data 56
Winter Weather0 of 56Insufficient Data 56

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.

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
No rows for this unit.

No city, town, township or county rows in FEMA plan data for this unit; same as county.

Supports FEMA checklist items B2-a and B2-b: vulnerability and potential impacts

Local data needed

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

  • Critical facilities and lifelines per hazard
  • A problem statement per jurisdiction per hazard
  • Changes in development in hazard-prone areas since the last approval, or a statement of none (E1-a)
  • Future 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 2024-07-25county-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$3,551,095,408n/a14,009$148,211n/a$2810.00417%
Cold Wave$0$00$0$0$0building exposure is 0 in NRI
Droughtn/an/an/an/an/an/a$0NRI publishes no agriculture exposure for this county
Earthquake$45,061,016,098n/a153,898$20,346,681n/a$6,005,1480.0452%
Hailn/an/an/an/an/an/aNRI publishes no building exposure for this county
Heat Wave$0$00$0$0$0building exposure is 0 in NRI
Hurricane$26,507,788,940$381,523153,310$140,265,531$6,329$8,434,5500.529%$436,500,000no Public Assistance recorded (3 declarations)Storm Events damage since the plan includes the zone-level Tropical Storm record of 2026-04-13 ($436,500,000; as recorded; larger than this county's annual agriculture value in the National Risk Index (the county or state extension service keeps crop loss records)).
Inland Flooding$0$26,0827,895$0$800$591,112n/a (see note)$2,500NRI 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.
Landsliden/an/an/an/an/an/a$15,000NRI publishes no building exposure for this county
Lightningn/an/an/an/an/an/aNRI publishes no building exposure for this county
Strong Windn/an/an/an/an/an/a$5,000NRI publishes no building exposure for this county Storm Events damage since the plan includes 1 zone-level Strong Wind record ($5,000): a NOAA non-thunderstorm wind type, outside NRI's Strong Wind definition.
Tornadon/an/an/an/an/an/aNRI publishes no building exposure for this county
Tsunami$3,879,220,117n/a1,833$413,777n/a$39,342,2470.0107%
Volcanic ActivityNot Applicable in NRI for this county
Wildfiren/an/an/an/an/an/aNRI publishes no building exposure for this county
Winter Weather$0$00$0$0$0building exposure is 0 in NRI

Totals since 2024-07-25 (Storm Events through 2026-06-30): 5 county-coded records, 5 with a damage value recorded (including $0), $17,500; 7 zone-level records, 5 with a damage value recorded (including $0), $436,505,000 reported for the zone; Public Assistance: none recorded on the 3 counted declarations.

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)

County context

Source: 5

MeasureValue
Population153,310
Building value (total, not at risk)$26,507,788,940
Agriculture value (total, not at risk)$381,523
NRI risk rating (all hazards)Insufficient Data
Expected annual loss, buildings and agriculture, all hazards$161,181,329
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)$54,373,338
Social vulnerability ratingData Unavailable
Community resilience ratingData Unavailable
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)1Severe repetitive loss, FMA definition (44 CFR 77.2)1
Repetitive loss, NFIP insurance definition16Severe repetitive loss, NFIP insurance definition1

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

Repeat-flood properties: county total and NFIP communities

Sources: 1, 4

ScopeRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
County total111611600
of which: Territory of Guam (community ID not in plan data)111611600

County repeat-flood properties by occupancy group

Sources: 1, 4

Occupancy groupRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
single-family residential111411400
2 to 4 unit residential0010100
other residential0000000
non-residential0010100
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 0 properties are FMA repetitive loss but not NFIP repetitive loss, and 15 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)

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). Guam, GU: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 66010). Automated baseline. https://hazardplain.org/gu/66010/ 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]