Automated baseline from FEMA and NOAA data, release 2026-10.

Napa County, CA

Risk-assessment baseline packet. County FIPS 06055. Release 2026-10, data as of 2026-09-30.

Summary

Plan status as of 2026-09-30: No approved plan on record.

Update: FEMA tracker shows a plan in review.

Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Inland Flooding ($89,760,025 a year), Earthquake ($66,769,665) and Drought ($21,364,139).

The packet's tables are organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B (B1-a to B2-c); the summaries below follow the same order.

Download the packet

Full packet as a web page. File manifest (checksums, source versions).

Plan clock

No approved plan on record

Plan:
none
Approved:
none
Expires:
none
Update underway:
FEMA tracker shows a plan in review

FEMA's plan status data lists no approved plan for this jurisdiction.

What changed since your last plan

No approved plan on record, so there is no approval date to count from.

Plan status for every jurisdiction listed in this county

12 jurisdictions. Each row is that jurisdiction's own plan clock. Notes include other approved plans FEMA lists for the same jurisdiction.

JurisdictionTypeStatusPlanApprovedExpiresDays to expirynegative = days since expiryUpdate underwayNotes
Napa CountyCountyNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review
American Canyon cityCityNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review
Calistoga cityCityNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review
Napa cityCityApproved, expires 2027-06-14Napa, City of (FEMA plan 108089)2022-06-152027-06-14257
St. Helena cityCityNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review
Yountville cityCityNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review
American Canyon Fire Protection DistrictFire/EMS DistrictNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review
Howell Mountain Mutual Water CoWater/Sewer AuthorityNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review
Napa County flood Control and Water Conservation DistrictFlood Control DistrictNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review
Napa County Office of EducationSchool/School DistrictNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review
Napa Valley CollegeCollege/UniversityNo approved plan on recordnonenonenoneFEMA tracker shows a plan in review
Napa Valley Transportation AuthorityTransit/AirportApproved, expires 2027-11-09Metropolitan Transportation Commission (FEMA plan 110161)2022-11-102027-11-09405FEMA tracker shows a plan in reviewthis jurisdiction approved 2022-11-16

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

What the packet contains

Sections in FEMA checklist order; each heading names the review item its tables support. Full tables are in the downloads above.

Supports FEMA checklist item B1-a Hazard identification

16 of the 18 National Risk Index hazards apply here.

Highest expected annual loss (NRI, modeled): Inland Flooding, Earthquake and Drought.

Not covered by NRI (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 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

  • Avalanche, Earthquake, Hurricane, Landslide, Tornado, Tsunami, Volcanic Activity and Wildfire vary within the county; the packet lists the highest-rated census tracts for each.
  • 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.
  • Cold Wave, Drought, Hail, Heat Wave, Ice Storm, Lightning, Strong Wind and Winter Weather: affects the whole county; national data give no location within it.

Supports FEMA checklist item B1-c Hazard extent

Storm Events records for 13 of the 20 NOAA event-type groups mapped to the 18 hazards, with the scale, observed range and worst recorded event for each; the others say which local data are needed.

Worst recorded tornado, hail and thunderstorm wind (the three event types on record since the 1950s; the packet has every group):

  • Hail: 1.75 in hail, 1983-08-19
  • Thunderstorm Wind: 57 kt (66 mph) measured gust, Thunderstorm Wind, 2020-08-16
  • Tornado: EF0 tornado, 2016-04-27, 0.19 mi within this county, 10 yd wide, damage not reported

Supports FEMA checklist item B1-d Previous occurrences

Federal declarations for this area: 39 declarations covering 29 separate hazard incidents counted in this packet; each with type, dates and county Public Assistance dollars.

No approved plan on record, so there is no approval date to count from.

10 statewide declarations listed separately.

Hazards with no Storm Events record and no federal declaration are stated as such (4 of 18).

Storm Events history: 327 records (notable ones in the PDF, all of them in the Excel file).

Supports FEMA checklist item B1-e Probability of future events

FEMA annualized frequency (modeled) for each hazard, with a descriptor from a scale defined in the packet.

  • Highly likely: Coastal Flooding, Landslide and Lightning
  • Likely: Heat Wave, Inland Flooding and Wildfire
  • Possible: Avalanche, Cold Wave, Hail, Strong Wind, Tornado and Winter Weather
  • Unlikely: Volcanic Activity

Historical frequency by intensity band (tornado, hail, wind): 9 bands from Storm Events.

Supports FEMA checklist item B1-f Hazards that vary across jurisdictions

Range of census tract risk scores within the area for 18 hazards (40 tracts; rated tracts only).

6 jurisdictions: plan clock, repeat-flood count, Public Assistance dollars and event records naming the place (starting figures from federal data).

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

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

No approved plan on record, so there is no approval date to count from.

Local data needed

To gather:

  • 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

Supports FEMA checklist item B2-a Vulnerability (county context)

Population 137,956; building value $37,677,326,480 and agriculture value $738,062,122 (total, not at risk).

National Risk Index rating Relatively High; social vulnerability Relatively Low; community resilience Relatively High.

Supports FEMA checklist item B2-c Repetitive loss properties

Repetitive-loss properties, FMA definition (44 CFR 77.2): 9 repetitive loss, 36 severe repetitive loss. NFIP insurance definition: 94 and 20.

Mitigated 11; insured 48; NFIP data as of 2026-08-02. Counts by occupancy group and for each jurisdiction are in the packet.

Releases

Each release is dated; this is release 2026-10. It was first published 2026-09-30; its files do not change. Later releases will be listed here with what changed between them. All releases.

Cite this

Hazard Plain (2026). Napa County, CA: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 06055). Automated baseline. https://hazardplain.org/ca/06055/ Built from FEMA OpenFEMA, the FEMA National Risk Index and NOAA NCEI Storm Events; source versions in the packet's Sources list.

Source citations for the plan's bibliography (8)

How this packet is built: methods and sources