Risk-assessment baseline packet. County area 42101. Release 2026-10, data as of 2026-09-28.
Plan clock
Approved, expires 2031-06-03
- Plan
- City of Philadelphia Hazard Mitigation Plan (FEMA plan 110755)
- Approved
- 2026-06-04
- Expires
- 2031-06-03
- As of
- 2026-09-28
- Days
- 1,709 days to expiry
Also approved under plan 108236 (City of Philadelphia Hazard Mitigation Plan, expires 2027-05-18). FEMA's plan status map shows one plan per jurisdiction and may show one of these; this packet uses the approved plan that expires last.
Plan clock from the consolidated city-county government plan (Philadelphia city). FEMA plan data has no separate county-level row for this county.
Map group: Covered beyond 24 months.
What the packet contains
Sections in FEMA checklist order. Each heading names the review item its tables support; whether the item is satisfied is decided by the plan and its reviewers. Full tables are in the downloads above.
Supports B1-a Hazards
16 of the 18 National Risk Index hazards apply here; omission evidence is shown only where NRI rates a hazard "Not Applicable", no federal declaration names it and Storm Events has no record of it since 1996.
Highest expected annual loss (NRI, modeled): Inland Flooding, Heat Wave and Cold Wave.
Also check locally (not covered by NRI): 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 and expansive soils.
Check your state hazard mitigation plan's hazard list for this county; explain any hazard you drop.
Supports B1-b Location
- Avalanche, Earthquake, Hurricane, Landslide, Tornado, Tsunami, Volcanic Activity and Wildfire: Census tract rating counts from the National Risk Index tract table (see B1-f). Tract maps and place names are not in this packet.
- 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 planning area; national data do not distinguish locations within the county. Confirm locally.
Supports B1-c Extent
Storm Events records for 15 of 20 hazard groups, with the scale, observed range and worst recorded event for each; the others say local data required.
- Hail: 1.75 in hail, 2009-03-29; same size also recorded on 1978-08-11, 1994-06-29, 1995-05-29, 2006-08-25
- Thunderstorm Wind: 87 kt (100 mph), measurement type not recorded, Thunderstorm Wind, 1992-08-11
- Tornado: EF3 tornado, 2021-07-29, 0.62 mi within this county, 530 yd wide, property not reported; $0 crops (2021 dollars)
Supports B1-d Previous occurrences
25 federal declaration rows for this area (18 counted incidents), each with type, dates and county Public Assistance dollars.
New since the last plan (approved 2026-06-04): none.
6 statewide declarations listed separately.
Hazards with no recorded events are stated as such (4 of 18).
Storm Events history: 1,285 records (notable ones in the PDF, all of them in the Excel file).
Supports B1-e Probability
FEMA annualized frequency (modeled) for each hazard, with a descriptor from a scale defined in the packet.
- Highly likely: Coastal Flooding, Hail, Heat Wave, Inland Flooding, Lightning, Strong Wind and Winter Weather
- Likely: Cold Wave and Drought
- Possible: Hurricane, Ice Storm, Landslide, Tornado and Wildfire
Historical frequency by intensity band (tornado, hail, wind): 9 bands from Storm Events.
Supports B1-f Variation across the planning area
Range of census tract risk scores within the area for 18 hazards (408 tracts; rated tracts only).
1 member jurisdiction: plan clock, repeat-flood count, Public Assistance dollars and event records naming the place (starter, confirm locally).
Supports B2-a, B2-b Assets and impacts
Local data required
County-level starter. The plan must describe impacts for each participant and its own assets.
Storm Events damage since 2026-06-04: $85,000 in county-coded records (16 records); none reported reported for the zone (1 zone record). Data through 2026-06-30; nominal dollars.
Checklist of what to gather locally: Critical facilities and lifelines per hazard; A problem statement per participant per hazard; Changes in development in hazard-prone areas since the last approval, or a statement of none (E1-a); Future assets.
Supports B2-a Context
Population 1,602,305; building value $291,673,614,404 and agriculture value $421,121 (total, not at risk).
National Risk Index rating Very High; social vulnerability Very High; community resilience Relatively Moderate.
Supports B2-c Repetitive loss
Repetitive-loss properties, FMA definition (44 CFR 77.2): 4 repetitive loss, 35 severe repetitive loss. NFIP insurance definition: 141 and 34.
Mitigated 0; insured 69; NFIP data as of 2026-08-02. Counts by occupancy and for each member community are in the packet.