Risk-assessment baseline packet (county-level sections from Chittenden County). Town FIPS 5000785150, Chittenden County. Release 2026-10, data as of 2026-09-30.
Summary
Plan status as of 2026-09-30: Approved, expires 2027-11-10. Plan: 2022 Chittenden County All Hazards Multi-Jurisdictional Hazard Mitigation Plan (FEMA plan 108641), approved 2022-11-11.
Sections B1-a, B1-b, B1-c, B1-d, B1-e, B2-a and B2-b use Chittenden County data (county FIPS 50007; each heading says so); the plan clock, B1-f and B2-c are for Winooski city.
Since the plan was approved on 2022-11-11: 6 new hazard declarations (5 incidents) and 89 NOAA Storm Events records (county-level); details under "What changed since your last plan".
Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Inland Flooding ($28,797,704 a year), Earthquake ($2,147,955) and Heat Wave ($1,797,421).
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.
What changed since your last plan (approved 2022-11-11)
- New federal declarations:
- 6 new hazard declarations (5 incidents): DR-4695-VT (Severe Storm and Flooding), EM-3595-VT (Flooding), DR-4720-VT (Severe Storms, Flooding, Landslides, and Mudslides), DR-4770-VT (Severe Winter Storm), EM-3609-VT (Tropical Depression Debby), DR-4810-VT (Severe Storm, Flooding, Landslides, and Mudslides)
- Storm Events records since approval (Chittenden County, county-level):
- 89 records (data through 2026-06-30)
- Repetitive loss now (this town):
- FMA RL 0, SRL 0 (44 CFR 77.2); any definition: 0
- Repetitive loss scope:
- This town's NFIP community only. The other participants of the town's plan (Bolton town; Buels gore; Burlington city; Charlotte town; Essex Junction village; Essex town; Hinesburg town; Huntington town; Jericho town; Milton town; Richmond town; Shelburne town; South Burlington city; St. George town; Underhill town; Westford town; Williston town) are not counted here; the B2-c county table lists a community only when FEMA's multiple-loss file has properties for it.
- Repeat-flood change:
- this release sets the baseline count.
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
County-level: Chittenden County.
15 of the 18 National Risk Index hazards apply here.
Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: coastal flooding, tsunami and volcanic activity. That is the evidence for leaving them out of the plan.
Highest expected annual loss (NRI, modeled): Inland Flooding, Earthquake and Heat Wave.
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
County-level: Chittenden County.
- Avalanche, Earthquake, Hurricane, Landslide, Tornado and Wildfire vary within the county; the packet lists the highest-rated census tracts for each.
- 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.
- 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.
Supports FEMA checklist item B1-c Hazard extent
County-level: Chittenden County.
Storm Events records for 11 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: 3.3 in hail, 2009-07-16
- Thunderstorm Wind: 70 kt (81 mph) estimated gust, Thunderstorm Wind, 2008-06-10; same speed and measurement basis also recorded on 2005-08-01
- Tornado: F2 tornado, 1983-08-08, 0.2 mi path length (whole path, pre-1996), 10 yd wide, $2,500,000 property; crops not recorded (1983 dollars)
Supports FEMA checklist item B1-d Previous occurrences
County-level: Chittenden County (federal declarations, statewide declarations and Storm Events history).
Federal declarations for this area: 32 declarations covering 27 separate hazard incidents counted in this packet; each with type, dates and county Public Assistance dollars.
New since the last plan (approved 2022-11-11): DR-4810-VT, EM-3609-VT, DR-4770-VT, DR-4720-VT, EM-3595-VT and DR-4695-VT.
2 statewide declarations listed separately.
Hazards with no Storm Events record and no federal declaration are stated as such (7 of 18).
Storm Events history: 1,008 records (notable ones in the PDF, all of them in the Excel file).
Supports FEMA checklist item B1-e Probability of future events
County-level: Chittenden County.
FEMA annualized frequency (modeled) for each hazard, with a descriptor from a scale defined in the packet.
- Highly likely: Hail, Lightning and Winter Weather
- Likely: Cold Wave, Heat Wave, Inland Flooding, Landslide and Strong Wind
- Possible: Avalanche, Hurricane, Ice Storm and Tornado
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 15 of the 18 hazards (41 tracts; rated tracts only).
1 jurisdiction: plan clock, repeat-flood count, Public Assistance dollars and event records naming the place (starting figures from federal data).
Supports FEMA checklist items B2-a and B2-b Vulnerability and potential impacts
County-level: Chittenden County (National Risk Index exposure and expected annual loss; since-plan counts use Winooski city's approval date).
The packet's table gives county-level starting figures; the plan describes impacts for each jurisdiction and its own assets.
Storm Events damage since 2022-11-11: $1,055,000 in county-coded records (34 records); $2,425,000 reported for the zone (55 zone records). Data through 2026-06-30; nominal dollars.
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
- Vermont Flood Ready Atlas and Agency of Natural Resources (ANR) river corridors for town flood and erosion locations.
- The Emergency Relief and Assistance Fund (ERAF) Flood Hazard Summary gives E911 building counts in the Special Flood Hazard Area (SFHA) per town.
- Vermont Dam Inventory for dams in and upstream of the town.
- Vermont Emergency Management (VEM) hazard mitigation planning resources and the 2023 Vermont State Hazard Mitigation Plan.
Supports FEMA checklist item B2-a Vulnerability (county context)
County-level: Chittenden County.
Population 168,162; building value $40,414,880,347 and agriculture value $56,100,811 (total, not at risk).
National Risk Index rating Relatively Low; social vulnerability Very Low; community resilience Very High.
Supports FEMA checklist item B2-c Repetitive loss properties
Repetitive-loss properties (Chittenden County, county-level), FMA definition (44 CFR 77.2): 1 repetitive loss, 2 severe repetitive loss. NFIP insurance definition: 14 and 1.
Mitigated 0; insured 8; NFIP data as of 2026-08-02. Counts by occupancy group and for each jurisdiction are in the packet.