Hazard Plain Automated baseline

Lyon County, NV

Risk-assessment baseline packet

County FIPS:
32019
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 2029-09-12. Plan: Lyon County (FEMA plan 109854), approved 2024-09-13.

Since the plan was approved on 2024-09-13: no new hazard declaration and 65 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): Earthquake ($11,715,249 a year), Inland Flooding ($11,108,198) and Wildfire ($7,377,311).

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 2029-09-12
Plan:
Lyon County (FEMA plan 109854)
Approved:
2024-09-13
Days to expiry:
1,078

What changed since your last plan (approved 2024-09-13)

New federal declarations:
none
Storm Events records since approval:
65 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 0, SRL 1 (44 CFR 77.2); any definition: 1
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
Lyon CountyCountyApproved, expires 2029-09-12Lyon County (FEMA plan 109854)2024-09-132029-09-121,078this jurisdiction approved 2024-09-12
Fernley cityCityApproved, expires 2029-09-12Lyon County (FEMA plan 109854)2024-09-132029-09-121,078this jurisdiction approved 2024-09-12
Yerington cityCityApproved, expires 2029-09-12Lyon County (FEMA plan 109854)2024-09-132029-09-121,078this jurisdiction approved 2024-09-12
Carson Water Subconservancy DistrictConservation DistrictApproved, expires 2029-09-12Lyon County (FEMA plan 109854)2024-09-132029-09-121,078this jurisdiction approved 2024-09-12
Central Lyon County Fire Protection DistrictFire/EMS DistrictApproved, expires 2029-09-12Lyon County (FEMA plan 109854)2024-09-132029-09-121,078this jurisdiction approved 2024-09-12
Mason and Smith Valley Conservation DistrictConservation DistrictApproved, expires 2029-09-12Lyon County (FEMA plan 109854)2024-09-132029-09-121,078this jurisdiction approved 2024-09-12
Mason Valley Fire Protection DistrictFire/EMS DistrictApproved, expires 2029-09-12Lyon County (FEMA plan 109854)2024-09-132029-09-121,078this jurisdiction approved 2024-09-12
North Lyon County Fire Protection DistrictFire/EMS DistrictApproved, expires 2029-09-12Lyon County (FEMA plan 109854)2024-09-132029-09-121,078this jurisdiction approved 2024-09-12
Smith Valley Fire Protection DistrictFire/EMS DistrictApproved, expires 2029-09-12Lyon County (FEMA plan 109854)2024-09-132029-09-121,078this jurisdiction approved 2024-09-12
Walker River Irrigation DistrictSpecial DistrictApproved, expires 2029-09-12Lyon County (FEMA plan 109854)2024-09-132029-09-121,078this jurisdiction approved 2024-09-12

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
1EarthquakeRelatively ModerateRelatively Moderate$8,545,581n/a$3,169,668$11,715,249Storm Events does not record earthquakes.
2Inland FloodingRelatively LowRelatively Low$10,429,478$511,126$167,594$11,108,19834
3WildfireRelatively ModerateRelatively Moderate$7,020,587$867$355,857$7,377,31120
4Heat WaveRelatively LowRelatively Low$245$26,869$866,283$893,3985
5DroughtRelatively ModerateRelatively Moderaten/a$570,317n/a$570,3170No recorded events in Storm Events since 1996 (data through 2026-06-30).
6Winter WeatherRelatively HighRelatively High$19,978under $1$455,882$475,860260
7LightningRelatively LowRelatively Low$9,758n/a$302,921$312,6792
8Strong WindRelatively LowRelatively Low$49,488$712$213,383$263,583772Includes 688 High Wind and 62 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
9HailVery LowRelatively Low$588$8,704$141,574$150,8667
10Ice StormRelatively LowRelatively Low$623n/a$43,161$43,7843
11TornadoVery LowVery Low$2,996$328$749$4,0733
12LandslideVery LowVery Low$241n/a$232$4736
13AvalancheVery LowVery Lowunder $1n/a$48$480No recorded events in Storm Events since 1996 (data through 2026-06-30).
14Volcanic ActivityVery LowVery Lowunder $1n/a$15$150No recorded events in Storm Events since 1996 (data through 2026-06-30).
15Cold WaveNo RatingNo Expected Annual Losses$0$0$0$01
HurricaneNot ApplicableNot Applicable0NRI rates hurricane Not Applicable for this county, and no counted federal declaration for this county names it (EM-3243-NV names it but is not counted as a local occurrence; see B1-d).No 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 volcanic activity records (Storm Events records this hazard only in part).

Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: coastal flooding and tsunami. 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, Ice Storm, Lightning, Strong Wind and Winter Weather.

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
Avalanchetract 9602.06 (Very Low, 12.8); tract 9608.02 (Very Low, 11.7); tract 9608.01 (Very Low, 11.6)
Earthquaketract 9609.01 (Relatively High, 95.2); tract 9601.03 (Relatively High, 94.1); tract 9608.01 (Relatively High, 92.8)
Hurricaneno tract has a National Risk Index rating for this hazard
Landslidetract 9603.03 (Relatively Low, 85.0); tract 9608.01 (Relatively Low, 81.8); tract 9608.02 (Relatively Low, 81.7)
Tornadotract 9601.03 (Very Low, 2.0); tract 9608.02 (Very Low, 1.9); tract 9603.03 (Very Low, 1.9)
Volcanic Activitytract 9608.01 (Very Low, 70.7); tract 9603.05 (Very Low, 70.5); tract 9603.03 (Very Low, 69.3)
Wildfiretract 9603.03 (Very High, 99.7); tract 9603.01 (Very High, 99.2); tract 9608.01 (Relatively High, 98.9)

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 9602.06 is Census Tract 9602.06). 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
Avalanchenone (count and damage only)0
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill1 record, 1997 (1 zone-level)3 days; 1 with a recorded value3 consecutive days, 1997-01-13 to 1997-01-15, zone-levelCountywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage0
DroughtU.S. Drought Monitor scale (D0 to D4)0Storm 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)10 records, 1982 to 20150.25 in to 1.75 in (median 1 in); 10 with a recorded value1.75 in hail, 1997-07-30; same size also recorded on 1982-07-28, 1986-06-13Hail, 2008-05-27, $5,000 property; $0 crops (2008 dollars)No event record names a jurisdiction in the plan.
Excessive Heat, Heatheat index (in event narratives)5 records, 2006 to 2022 (5 zone-level)3 days to 13 days (median 3 days); 3 with a recorded value13 consecutive days, 2006-07-16 to 2006-07-28, zone-levelCountywide (zone-level records).
Hurricane, Tropical Storm, Tropical DepressionSaffir-Simpson0Storm 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)3 records, 2005 to 2007 (3 zone-level)Ice Storm, 2006-12-21, $25,000 property; $0 crops (2006 dollars); NWS zone NVZ004Countywide (zone-level records).
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)34 records, 1996 to 2026 (3 zone-level)Flood, 1997-01-01, $640,000,000 property; crops not reported (1997 dollars), 50 direct injuries (reported for the zone); NWS zone NVZ001Event records naming jurisdictions in the plan: Fernley city (6 records). Zone-level records (3) 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)6 records, 2009 to 2023 (1 zone-level)Debris Flow, 2013-09-14, $5,000 property; $0 crops (2013 dollars)No event record names a jurisdiction in the plan. Zone-level records (1) apply countywide.
Lightningannualized frequency (the measure FEMA's Local Mitigation Planning Handbook names)2 records, 2004 to 2007Lightning, 2007-07-06, $40,000 property; $0 crops (2007 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)750 records, 1996 to 2026 (750 zone-level)23 kt (26 mph) to 132 kt (152 mph) (median 57 kt (66 mph)); 741 with a recorded value132 kt (152 mph), measurement type not recorded, High Wind, 1999-02-06; NWS zone NVZ003High Wind, 2022-12-30, $5,000,000 property; $0 crops (zone total, 2022 dollars)Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)30 records, 1979 to 202650 kt (58 mph) to 87 kt (100 mph) (median 52 kt (60 mph)); 24 with a recorded value87 kt (100 mph) estimated gust, Thunderstorm Wind, 2017-07-24Thunderstorm Wind, 2002-07-12, $50,000 property; $0 crops (2002 dollars)Event records naming jurisdictions in the plan: Yerington city (6 records), Fernley city (4 records).
TornadoEnhanced Fujita (Fujita before Feb 2007)4 records, 1989 to 1998F/EF0; 4 with a recorded valueF0 tornado, 1989-06-07, 1 mi path length (whole path, pre-1996), 10 yd wide, $2,500 property; crops not recorded (1989 dollars)Event records naming jurisdictions in the plan: Fernley city (2 records).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).
Volcanic Ash, Volcanic AshfallVolcanic Explosivity Index (local data)0
Wildfireacres burned (local data)20 records, 2009 to 2025 (20 zone-level)Wildfire, 2016-10-14, $30,000,000 property; $0 crops (2016 dollars); NWS zone NVZ003Countywide (zone-level records).
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)260 records, 1996 to 2026 (259 zone-level)Winter Storm, 2022-12-30, $5,000,000 property; $0 crops (2022 dollars); NWS zone NVZ001Event records naming jurisdictions in the plan: Fernley city (1 record). Zone-level records (259) apply countywide.

In event narratives only (local data needed): wind chill, temperature, heat index, ice thickness, acres burned and snow depth; any physical measure of avalanche, debris flow, lightning 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: 14 declarations covering 11 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
2023-04-272023-03-08DR-4708-NVMajor disasterSevere Winter Storms, Flooding, Landslides, and MudslidesInland Flooding (primary); also designated: Landslide, Winter Weather$1,070,914.83within last 5 years
2020-04-042020-01-20DR-4523-NVMajor disasterCOVID-19 PandemicNon-natural, not counted$33,980.48
2020-03-132020-01-20EM-3443-NVEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedsame incident as DR-4523
2018-06-172018-06-17FM-5242-NVFire managementUpper Colony FireWildfireno Public Assistance recorded
2017-02-172017-01-05DR-4303-NVMajor disasterSevere Winter Storms, Flooding, and MudslidesInland Flooding; Landslide; Winter Weather$278,095.83
2008-01-082008-01-05DR-1738-NVMajor disasterSevere Winter Storms and FloodingInland Flooding; Winter Weather$682,921.35
2006-06-272006-06-26FM-2650-NVFire managementLinehan Fire ComplexWildfireno Public Assistance recorded
2006-02-032005-12-31DR-1629-NVMajor disasterSevere Storms and FloodingInland Flooding$220,990.65
2005-09-132005-08-29EM-3243-NVEmergencyHurricane Katrina EvacuationHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
2005-02-232005-01-06EM-3204-NVEmergencySnowWinter Weather$21,331.64
2005-02-172004-12-29EM-3202-NVEmergencyRecord and/or Near Record SnowWinter Weatherno Public Assistance recorded
1997-01-031996-12-20DR-1153-NVMajor disasterSevere Storms, Flooding, Mud and LandslidesInland Flooding; Landslideno Public Assistance recorded
1986-02-281986-02-15DR-759-NVMajor disasterSevere Storms & FloodingInland Floodingno Public Assistance recorded
1965-01-181965-01-18DR-187-NVMajor disasterSevere Storms, Heavy Rains & FloodingInland Floodingno Public Assistance recorded

School districts and special districts in this county: $302,518.35 (included in the county total above). Public Assistance matched by applicant name to the school districts and special districts FEMA lists as plan participants in this county. They have no row of their own in the jurisdiction table, so their total is listed here. These dollars are already included in the county PA column of the declarations table (the FEMA record places each applicant in this county), so this line is not added to it.

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
1963-02-141963-02-14DR-142-NVMajor disasterFloodsInland Flooding
1962-02-221962-02-22DR-121-NVMajor disasterFloodsInland Flooding
1956-08-311956-08-31DR-63-NVMajor disasterFloodInland Flooding
1955-12-241955-12-24DR-48-NVMajor disasterFloodInland Flooding
1955-06-211955-06-21DR-36-NVMajor disasterFloodInland Flooding
1954-07-141954-07-14DR-19-NVMajor disasterEarthquakeEarthquake

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.

12 Fire Management declarations (1979-06-11 to 1999-08-25) 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
Avalanche0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Cold Wave1000001996 to 2026-06-30
Drought0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail10000001955 to 2026-06-30
Heat Wave5001001996 to 2026-06-30
Hurricane0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Ice Storm3000001996 to 2026-06-30
Inland Flooding34216701996 to 2026-06-30
Landslide6003301996 to 2026-06-30
Lightning2000001996 to 2026-06-30
Strong Wind7805022118001955 to 2026-06-30Includes 688 High Wind and 62 Strong Wind records.
Tornado4000001950 to 2026-06-30
Volcanic Activity0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Wildfire20112201996 to 2026-06-30
Winter Weather26012856501996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2022-12-30Winter Storm$5,000,000 property; $0 crops (zone total, 2022 dollars)0, 0NWS zone NVZ001 (MINERAL/SOUTHERN LYON), zone-levelwithin last 5 yearsB1-c worst recorded: Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet
2017-07-24Thunderstorm Wind87 kt (100 mph) estimated gustproperty not reported; $0 crops (2017 dollars)0, 0ARGO SIDING to FERNLEYB1-c worst recorded: Thunderstorm Wind
2016-10-14Wildfire$30,000,000 property; $0 crops (zone total, 2016 dollars)0, 0NWS zone NVZ003 (GREATER RENO/CARSON CITY/MINDEN AREA), zone-levelB1-c worst recorded: Wildfire
2007-07-06Lightning$40,000 property; $0 crops (2007 dollars)0, 0DAYTONB1-c worst recorded: Lightning
2006-12-21Ice Storm$25,000 property; $0 crops (zone total, 2006 dollars)0, 0NWS zone NVZ004 (WESTERN NEVADA BASIN AND RANGE), zone-levelB1-c worst recorded: Ice Storm
2006-07-16Heatdamage not reported0, 0NWS zone NVZ003 (GREATER RENO/CARSON CITY/MINDEN AREA), zone-levelB1-c worst recorded: Excessive Heat, Heat
2002-11-07High Wind61 kt (70 mph) estimated$250,000 property; crops not reported (zone total, 2002 dollars)1, 6NWS zone NVZ004 (WESTERN NEVADA BASIN AND RANGE), zone-leveldeaths or injuries recorded
2002-03-07Winter Storm$150,000 property; crops not reported (zone total, 2002 dollars)2, 0NWS zone NVZ004 (PERSHING/CHURCHILL/X SE WASHOE/NC&NE LYON), zone-leveldeaths or injuries recorded
1999-02-06High Wind132 kt (152 mph), measurement type not recorded$0 property; crops not reported (zone total, 1999 dollars)0, 0NWS zone NVZ003 (S WASHOE T X SE & X SW/STOREY/E CARSON CITY/C&E DOUGLAS/NW LYON), zone-levelB1-c worst recorded: High Wind and Strong Wind
1998-12-19Winter Storm$150,000 property; crops not reported (zone total, 1998 dollars)1, 10NWS zone NVZ003 (GREATER RENO/CARSON CITY/MINDEN AREA), zone-leveldeaths or injuries recorded
1997-07-30Hail1.75 indamage not reported0, 0DAYTONB1-c worst recorded: Hail
1997-01-01Flood$640,000,000 property; crops not reported (zone total, 1997 dollars)0, 50NWS zone NVZ001 (MINERAL/SOUTHERN LYON), zone-levelB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood

The full list is in the Excel file, sheet "B1-d Storm Events history" (1,125 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

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
Avalanche0.01events per yearabout 1 in 100 yearsPossibleFEMA annualized frequency (modeled)01994 to 2023 (30 years)see B1-f0.01 is NRI's minimum avalanche frequency for a county in an avalanche susceptibility zone; NRI records no avalanche here, so the descriptor reflects the floor, not local events.
Cold Wave0event-days per yearnone modeledPossibleStorm Events event-days in 1 of 30 years, 1996 to 2025 (3.33%)02005-11-12 to 2024-11-12 (19 years)countywideNRI models no cold wave event-days here (2005-11-12 to 2024-11-12, 19 years); Storm Events has a record in 1 of 30 years. The descriptor comes from Storm Events, which records events NRI's definition leaves out.
Drought98.9event-days per yearabout 98.9 days per yearStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)3,2832000 to 2025 (25.25 years; D3 and D4 only)countywideNo Storm Events drought record, 1996 to 2025
Earthquake0.0457annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 4.57%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail0.149events per yearabout 1 in 7 yearsLikelyFEMA annualized frequency (modeled)5.6 (modeled)1986 to 2023 (38 years)countywide
Heat Wave4event-days per yearabout 4 days per yearLikelyStorm Events event-days in 3 of 30 years, 1996 to 2025 (10%)592005-11-12 to 2024-11-12 (19 years)countywide
Hurricaneevents per year1851 to 2024 (Atlantic); 1949 to 2024 (Pacific)see B1-fNot Applicable in NRI for this county; no descriptor.
Ice Storm0.0149event-days per yearabout 0.0149 days per yearLikelyStorm Events event-days in 3 of 30 years, 1996 to 2025 (10%)01946-12-31 to 2014-02-12 (67 years)countywide
Inland Flooding1event-day per yearabout 1 day per yearLikelyStorm Events event-days in 17 of 30 years, 1996 to 2025 (56.7%)281996 to 2023 (28 years)see B1-f
Landslide3.97events per year (modeled)about 3.97 per yearHighly likelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning18.2days per year with a strikeabout 18.2 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind0.154events per yearabout 1 in 7 yearsLikelyFEMA annualized frequency (modeled)61986 to 2023 (38 years)countywide
Tornado0.0651events per yearabout 1 in 15 yearsPossibleFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Volcanic Activity0.0007annual probabilityabout 1 in 1,429 yearsUnlikelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Wildfire0.00533annual probability at a locationchance a given location in the county burns in a year: 0.533%LikelyStorm Events records in 10 of 30 years, 1996 to 2025 (33.3%)not shownmodeledsee B1-f
Winter Weather6.51event-days per yearabout 6.51 days per yearHighly likelyStorm Events event-days in 30 of 30 years, 1996 to 2025 (100%)1242005-11-12 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 20255300.167
Hail2.00 in+1996 to 20250300
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 202514300.467
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 20254300.133
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 20253300.1
TornadoEF0-11996 to 20253300.1
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
Avalanche10 of 188.710.812.8Very Low 10, Not Applicable 8
Cold Wave0 of 18No Rating 18
Drought16 of 1870.483.897.8Relatively High 1, Relatively Moderate 2, Relatively Low 8, Very Low 5, No Rating 2
Earthquake18 of 1880.886.595.2Relatively High 7, Relatively Moderate 11
Hail18 of 1841.749.867.3Relatively Low 18
Heat Wave18 of 1833.458.770.1Relatively Moderate 11, Relatively Low 7
Hurricane0 of 18Not Applicable 18
Ice Storm18 of 1820.430.647.9Relatively Low 6, Very Low 12
Inland Flooding18 of 1813.951.188.4Relatively High 1, Relatively Moderate 10, Relatively Low 6, Very Low 1
Landslide15 of 189.062.885.0Relatively Low 3, Very Low 12, No Rating 3
Lightning18 of 1850.461.183.3Relatively High 2, Relatively Moderate 16
Strong Wind18 of 1835.045.861.6Relatively Moderate 2, Relatively Low 16
Tornado18 of 180.91.52.0Very Low 18
Volcanic Activity18 of 1845.455.570.7Very Low 18
Wildfire18 of 1830.694.399.7Very High 2, Relatively High 4, Relatively Moderate 5, Relatively Low 3, Very Low 4
Winter Weather18 of 1887.893.099.2Very High 3, Relatively High 15

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 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
Lyon CountyCountyApproved, expires 2029-09-12FMA RL 0, SRL 1; any 1$1,357,274.400 total; 0 since its planIncludes $33,980.48 for declarations not counted as hazard incidents (DR-4523-NV).
Fernley cityCityApproved, expires 2029-09-12FMA RL 0, SRL 0; any 0$616,843.5313 total; 0 since its plan
Yerington cityCityApproved, expires 2029-09-12FMA RL 0, SRL 0; any 0no Public Assistance recorded6 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).

School districts and special districts get a plan clock row only.

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

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 2024-09-13county-coded records, property plus crops, nominal dollarsZone-level damage since planproperty plus crops, reported for the zonePublic Assistance since plannominal dollars; see noteNote
Avalanche$45,705n/aunder 1under $1n/a$48under 0.0001%
Cold Wave$0$00$0$0$0building exposure is 0 in NRI
Droughtn/a$27,405,233n/an/a$570,317n/a2.08% (agriculture)NRI has no building exposure for this hazard; agriculture shown
Earthquake$21,444,014,252n/a59,235$8,545,581n/a$3,169,6680.0399%
Hail$11,960,473,816$132,240,72559,117$588$8,704$141,574under 0.0001%
Heat Wave$11,960,473,816$132,240,72559,117$245$26,869$866,283under 0.0001%
HurricaneNot Applicable in NRI for this county
Ice Storm$11,960,473,816n/a59,117$623n/a$43,161under 0.0001%
Inland Flooding$11,955,105,695$34,282,8072,713$10,429,478$511,126$167,594n/a (see note)$0NRI 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$140,929,419n/a325$241n/a$2320.000171%
Lightning$11,960,473,816n/a59,117$9,758n/a$302,921under 0.0001%
Strong Wind$11,960,473,816$132,240,72559,117$49,488$712$213,3830.000414%$0$100,000Storm Events damage since the plan includes 1 zone-level High Wind record ($100,000): a NOAA non-thunderstorm wind type, outside NRI's Strong Wind definition.
Tornado$11,960,473,816$132,240,72559,117$2,996$328$749under 0.0001%
Volcanic Activity$11,960,473,816n/a59,117under $1n/a$15under 0.0001%
Wildfire$2,735,570,267$50,362,29218,539$7,020,587$867$355,8570.257%$0
Winter Weather$11,960,473,816$132,240,72559,117$19,978under $1$455,8820.000167%$0

Totals since 2024-09-13 (Storm Events through 2026-06-30): 5 county-coded records, 5 with a damage value recorded (including $0), $0; 60 zone-level records, 52 with a damage value recorded (including $0), $100,000 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)

County context

Source: 5

MeasureValue
Population59,117
Building value (total, not at risk)$11,960,473,816
Agriculture value (total, not at risk)$132,240,725
NRI risk rating (all hazards)Relatively Low
Expected annual loss, buildings and agriculture, all hazards$27,198,487
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)$5,717,367
Social vulnerability ratingRelatively Low
Community resilience ratingVery Low
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)0Severe repetitive loss, FMA definition (44 CFR 77.2)1
Repetitive loss, NFIP insurance definition1Severe 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 and state-level rows

Sources: 1, 4

ScopeRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
County total0111100
of which: Lyon County (unincorporated area)0111100
Statewide, no county in FEMA's file0010100

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
Lyon County3200290111100
Fernley city3200380000000
Yerington city3200160000000

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 residential0111100
2 to 4 unit residential0000000
other residential0000000
non-residential0000000
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 1 property is 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). Lyon County, NV: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 32019). Automated baseline. https://hazardplain.org/nv/32019/ 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]