Methods, sources and limits

What a packet does, and does not do

FEMA's National Risk Index fact sheet says the dataset does not generate the risk assessment portion of the plan. Neither does this packet. It gathers the federal data a risk assessment starts from, so the planning team can spend its time on local knowledge and review.

It does

• Show the plan clock for every jurisdiction FEMA lists in the county's plan: status, approval date, expiry, days to or since expiry, and whether an update is underway.
• List the 18 National Risk Index hazards, which apply and which NRI marks "Not applicable", ranked by modeled expected annual loss, with a list of hazards NRI does not cover to check locally.
• List federal disaster and emergency declarations with county Public Assistance dollars, flag those new since the last plan's approval, and state "no recorded events" for hazards with neither a Storm Events record nor a federal declaration.
• Summarize NOAA Storm Events records: the scale, observed range and worst recorded event per hazard, and historical frequency by intensity (tornado rating, hail size, wind speed).
• Give FEMA's modeled annual frequency per hazard, with a probability descriptor from a scale defined in the packet. For earthquake, wildfire, coastal flooding and tsunami, FEMA's value is the chance at a location in the county, not how often the hazard affects the county, so it is labeled that way, gets no "1 in N years", and the descriptor comes from Storm Events (none for earthquake).
• Count repetitive-loss and severe repetitive-loss flood properties for the county and each member community (counts only).
• Offer a county-level starter table for assets and impacts, and a checklist of what to gather locally.
• Carry a citation line on every table for the plan's bibliography, and a "What changed since your last plan" box.

It does not

• Write the plan, its narrative, its mitigation strategy or its goals.
• Replace local data, local knowledge, the state plan or FEMA review. Items marked "Local data required" need information only the community has.
• Decide whether a plan satisfies any FEMA review element. Headings say which item a table supports; the plan and its reviewers decide the rest.
• Adjust dollars for inflation, estimate losses for individual buildings, or model future conditions.
• Include state-declared emergencies (there is no national source; each packet points to the state).

FEMA's own guidance leaves the format to the plan:

• There is no prescribed method for how to present this information (FEMA Local Mitigation Planning Policy Guide (2025), p. 18)
• FEMA does not require any specific format (FEMA Local Mitigation Planning Policy Guide (2025), p. 13)
• does not generate the risk assessment portion of the plan (FEMA National Risk Index fact sheet)

FEMA's Local Mitigation Planning Handbook names the same federal sources used here: NOAA Storm Events, OpenFEMA declarations and the National Risk Index.

How to read the labels

Preview: automated baseline

The packet was built automatically and passed the pipeline's quality checks, but has not been checked by hand. Most packets in this release carry this label.

Preview release, hand-checked on (date)

The packet was also checked line by line against the FEMA and NOAA sources on that date, and every issue found was fixed or explained. Its page and every file say so: "This packet was hand-checked against FEMA and NOAA sources on (date); other packets are automated and not yet checked by hand." It is still a preview release: check every figure against your own records.

Supports B1-a (and the other items)

The FEMA review item the section's tables are evidence for. It never means the item is satisfied.

Local data required

Federal data cannot fill this item. The packet gives a starter table and a checklist.

Modeled

A National Risk Index value from FEMA's model, not a count of events. "FEMA annualized frequency (modeled)" is not events divided by years.

Zone-level

A Storm Events record filed for a National Weather Service forecast zone, not a county. The zone may cover more than one county, so the event may have happened elsewhere in the zone. Zone damage is never added up across counties.

County-level (Vermont towns)

Town packets have their own plan clock and repeat-flood counts; hazard, probability and declaration tables come from the county and say so.

New since last plan and during plan review, check

A declaration after the current plan's approval date is new; one in the 12 months before approval may or may not be in the plan, so check.

Nominal dollars

Dollars as reported, labeled with their year; not adjusted for inflation.

How the plan clock is set

• Each jurisdiction is keyed by its type and Census code, so a school district and a city with the same number stay apart.
• The current plan is the Approved or Amending plan with the latest expiration date. A past expiration date wins over an "Approved" label (the packet notes "FEMA status not yet updated"). Without an approved plan, the latest expired plan is shown; without either, "no approved plan on record".
• A plan that is Approvable Pending Adoption is not yet approved and is never the current plan.
• A newer plan FEMA's tracker shows as in progress, in review, awaiting revisions or pending adoption is shown as "update underway". That comes from FEMA's tracker, which can be out of date.
• When a jurisdiction is in more than one approved plan, the packet uses the one that expires last and names the others. FEMA's plan status map shows one plan per jurisdiction and may show a different one.
• An expired plan: Generally not eligible for FEMA mitigation project grants (HMGP, FMA) until a new plan is approved, barring a 44 CFR 201.6(a)(3) exception. Planning grants are not affected.
• The home map groups county areas by their own plan row: lapsed, not yet adopted or never covered (a plan FEMA approved or found approvable but not adopted here counts in this group), expiring within 12 months, 12 to 24 months, beyond 24 months, or absent from FEMA plan data (common in New England, where towns hold the plans).

Data-error screens

A few source values are clearly wrong. The packet leaves such a value out and says so; it never replaces it with a corrected figure, and the record still counts as an occurrence unless it is an exact duplicate.

• Thunderstorm wind above 130 knots is not treated as a speed (likely a data entry error, such as a hail size typed into the wind field). It is left out of the worst event, the observed range and the intensity bands, and the county's wind line says a value was left out. One Oklahoma record (Canadian County, 2011-05-24) is a real gust measured as the El Reno tornado passed; it is left out as a tornado wind, with that reason.
• Tornado path length and width. Lengths above 220 miles, 200 miles or more from 1996 on, or (from 1996 on) 50 miles or more when that is over three times the straight-line distance between the recorded start and end points plus 20 miles, print as "length not shown: implausible value in source". Widths above 4,600 yards likewise. A length of 0 is not printed. Lengths never rank tornadoes.
• Duplicate tornado records (same county coding, rating, date, time, places and coordinates, with length and width identical or swapped) count once.
• Zone records cannot be a county's worst. For tornado, hail and thunderstorm wind, a record that reached a county only through a forecast zone covering more than one county is counted, but cannot be the county's worst event or set its observed range, because it may have happened in another county. When no other record exists, the packet says so.
• Hail size. Sizes under 0.20 inch are treated as not measured; the placeholder 9.99 is dropped; sizes of 8 inches or more stay as recorded with a note to verify (8 inches is about the U.S. record).
• Blank fields stored as zero. Before 1996 the Storm Events file stores 0 for tornado length and width on wind and hail rows; they are read as blank. Damage entered as "0T" or "0?" is read as not reported, not zero.
• County codes that are zones. A record coded to a county whose place name is really a forecast zone name is placed as a zone record. A county-coded record whose name names a different county, or whose code is not a county, is left out of county counts (mostly Puerto Rico records from 2000 to 2008).
• Impossible plan dates (such as the years 1025 and 3025) are not shown. A member approval date more than 5 years from the plan's approval is shown with a note that it may belong to an earlier plan.

Source quirks shown as recorded

• Tornadoes before 1996 are listed once, under the county where they began, with the whole path's rating and length. Counties farther along the path may not list them, and lengths from those years can be the whole path.
• Tornado records printed as published: two Brazos County, Texas records of 1995-05-18 (both count; their begin locations differ), and a Berkshire County, Massachusetts F4 of 1995-05-29 whose damage is published as $250 although the event's documented loss was far larger. No value is substituted.
• Zone records from 1996 to 2019 whose zone is in no known National Weather Service zone file cannot be placed in a county and are left out of counts, so counts for those years can be low. An older record is placed by its zone number only when its zone name matches the zone file; records from zones the Weather Service later renumbered (Hawaii, Alaska, Colorado, Oregon, Washington, Wyoming and others) are placed by name from a reviewed list, or left out. Zone files are matched by date from 2020 on.
• Guam, the Northern Mariana Islands and American Samoa records are placed by island name, not by zone number. Records for Palau, the Federated States of Micronesia, the Marshall Islands and Wake Island, which Storm Events files under Guam, are left out. The 33 records Storm Events files for the "Northern Marianas" area (the Commonwealth outside Saipan and Rota; typhoons including Super Typhoon Yutu of 2018-10-24, a volcanic ash fall and two rip currents) are placed in the Northern Islands Municipality only, because a record for the whole area cannot be told apart from one about the northern islands. The Northern Islands Municipality is not a National Risk Index county area, so these records appear in no packet, and Tinian has no Storm Events record.
• Older zone names that list several counties ("Sedgwick and Phillips Counties", Colorado; "Stillwater/Carbon", Montana; "Catalina and Santa Barbara Islands", California; and 48 other older names in the West, Virginia and Puerto Rico) are placed in every county the name lists, not only in the county of the zone that now carries the number.
• Augusta and Albemarle counties, Virginia are missing from the Weather Service zones named after them; Hazard Plain adds them back (and Indiana County, Pennsylvania, which two zone files list under a mistyped code). Every zone file lists the Colorado zone "Saguache County East of Continental Divide" with Rio Grande County under the correct spelling and Saguache County under a misspelling ("Saquache"); Hazard Plain places it in Saguache County only.
• Kalawao County, Hawaii has no Storm Events record at all; its "no recorded events" lines say why.
• Lightning in the island territories: NRI publishes no lightning frequency for American Samoa, Guam, the Northern Mariana Islands and the U.S. Virgin Islands, so no descriptor is given.
• Connecticut: plans and declarations use the former counties; NRI uses the nine planning regions. Declarations are listed on every overlapping region, labeled "former county". A few Connecticut flood properties match no town and are reported at state level.
• FEMA plan labels that lag: some plans still labeled Approved have passed their expiration date; the date is used.

Limitations

• The packet is a starting point. Assets, impacts and vulnerability for each participant (B2-a, B2-b) need local data; the county-level starter table does not describe individual jurisdictions.
• National Risk Index values are modeled and fixed at version 1.20 (December 2025). They describe the county as a whole; the tract range shows spread, not location.
• Storm Events is not a complete record of every event. Before 1996 it holds only tornado, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service and are often estimates or blank.
• Drought extent uses National Weather Service drought reports, not U.S. Drought Monitor county statistics. Earthquake and other hazards without a Storm Events measure say "local data required".
• FEMA's plan tracker can lag, and some "plan in progress" records have no date and may be stale.
• State-declared emergencies are not included; each packet points to the state.
• Member-level Public Assistance dollars depend on matching applicant names to jurisdictions and may miss some.
• State plans, tribal plans, statewide Public Assistance applicants and tribal declarations are on each state page and in the state files (state.xlsx and state.json in the state folder and the state ZIP), not on county pages. Public Assistance that FEMA files under a county field that is not a county of the state (for example an Alaska school area) is placed by applicant where the name identifies one place; the rest is listed on the state page and in every packet of the state. Public Assistance rows that FEMA files under a tribal government in place of a state (for example Fort Mojave Indian Tribe) have no state and are on no page yet.
• Packets, tables and pages are CC BY 4.0 (reuse with credit to Hazard Plain and the release); the federal source data are public domain, and OpenFEMA data are also subject to the OpenFEMA terms. Each packet, state file and bulk file carries the reuse line, a "Cite this" line and the corrections contact.
• A place that spans counties appears on every county page FEMA lists it under.
• Repeat-flood data are counts for the county and each community. No property detail (addresses, dates or dollars) is published.
• The map leaves out American Samoa, Guam, the Northern Mariana Islands and the U.S. Virgin Islands (not in the Census map file used); their state pages list every unit.

Known edge cases in this release

Two independent rebuilds of every packet's core figures from the same public files agreed with the packets on more than 99.8% of values. The cases below are where they did not agree and the right reading is not settled. They are left as described here; check them against your own records.

• Vermont Public Assistance filed under a bare name. A Vermont applicant filed with no "Town of", "City of" or "Village of" (for example "Colchester" or "Williamstown") is not credited to any town, because in Vermont the same name can belong to a town, a village, a fire district or another body. Those dollars still count in the county's Public Assistance, so a town page can show less than FEMA paid the town, or "none found" (Colchester, for example).
• Other Vermont town Public Assistance. In a few towns (Barton, Bethel, Brandon, Sharon, Washington, West Fairlee, Weston and Winhall) the town total or the part since the town's plan differs from another reading of which applicant names and disasters belong to the town. Vermont towns with no row in FEMA plan data show no town Public Assistance figure (a blank, not zero).
• Michigan, May 2020 Midland dam failures (DR-4547). FEMA's incident type is Dam/Levee Break, but the title names severe storms and flooding, so it is counted as an Inland Flooding declaration in Arenac, Gladwin, Iosco, Midland and Saginaw counties. Another reading would not count it.
• Alaska forecast zones. Chugach and Copper River census areas (split from Valdez-Cordova in 2019) receive zone records for the whole former area, so their Storm Events counts are higher than a reading that places each zone in one area. Anchorage, Bethel, Fairbanks North Star, Matanuska-Susitna and Yukon-Koyukuk differ by a few records.
• Puerto Rico forecast zones. Flood and wind counts in Dorado, Guayama, Humacao and Vieques depend on how zone records are placed in municipios and can differ from another reading in either direction.
• Southeastern Connecticut Planning Region. The member Public Assistance total includes $115,589.80 that another reading places outside the region's towns.
• Bedford County, Virginia. Records filed under the former city of Bedford, which joined the county in 2013, are counted in the county, so its hail, flood, lightning and wind counts are a little higher than a county-only reading.
• Wakulla County, Florida. The worst hail is 2.75 inches on 1995-06-10, as NOAA records it for the county; another reading leaves that record out and gives 1.75 inches on 2010-01-21.
• One-record differences. Perry County, Illinois (hail) and Washington County, Virginia (wind) count one Storm Events record fewer than another reading.
• Rules that can be read two ways. The two rebuilds also differed where the rule itself allows two readings: an area whose only plan is waiting for local adoption (shown here as an update, not as the current plan); which Vermont and Connecticut applicant name forms belong to which town; whether a town with no flood community on record shows a blank or zero repeat-flood count; which older zone names in western states match a county; county-coded records in "City" units (Baltimore city, Carson City, Charles City County); and one Davidson County, North Carolina tornado pair counted once as a duplicate. The packets follow the reading described on this page.

How to cite

Each jurisdiction page has a "Cite this" line with the exact text. The pattern is:

Hazard Plain (year). Jurisdiction, ST: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-28; unit type and code). Preview: automated baseline.

On a hand-checked packet the label in that line reads "Preview release, hand-checked on (date)", as on its page.

For the plan's bibliography (FEMA element A4-a), cite the federal sources themselves. Every table in a packet carries its source line; the sources of this release are:

• FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-26T121003Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
• FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-27T010817Z, pulled 2026-09-28, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
• FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-26T151157Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
• FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-28, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
• FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-28, 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)
• NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-28, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
• NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-28, https://www.weather.gov/gis/ZoneCounty
• U.S. Census Bureau, Census 2024 Gazetteer, 2020 place by county, CT county-to-cousub crosswalk, version 2024-gazetteer, pulled 2026-09-28, 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

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).

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.