Chittenden County, VT climate risk
FEMA rates none of the 7 reviewed hazards as Very High in Chittenden County, VT. Modeled losses from natural hazards (expected annual loss) average about $40 million a year, for a population of 168,162. These county figures come from the FEMA National Risk Index, December 2025 release. Observation windows vary by metric and sit beside the tables below.
Is Chittenden County at risk of flooding?
FEMA labels riverine flooding Relatively Moderate and coastal flooding Not Applicable. Modeled annual riverine flood loss is $28,797,704; coastal flood loss is Not Applicable. These are separate hazards and county totals. A rating describes relative county risk. It does not locate water at a building or establish a flood zone. Read missing statuses using the source documentation. Keep both source labels when comparing counties. Read the county rating versus flood-zone guide before requesting a location check.
What natural hazards affect Chittenden County most?
| Hazard | Source label | Observation window |
|---|---|---|
| Coastal flooding | Not Applicable | 1996-2023 |
| Riverine flooding | Relatively Moderate | 1996-2023 |
| Hurricane | Relatively Low | 1851-2024 |
| Wildfire | Very Low | 1996-2023 |
| Earthquake | Relatively Low | 1996-2023 |
| Tornado | Relatively Low | 1950-2023 |
| Heat wave | Relatively Low | 2005-2024 |
How have heat and rain changed in Chittenden County?
From 1991–2000 to 2016–2025, hot days near Chittenden County changed from 0.0 to 0.1 per year. Heavy-rain days changed from 0.2 to 0.2. The table retains humid heat, warm nights and maximum daily rain. Compare the periods alongside the source notes. These decade means describe past conditions; they do not predict a future year or establish a trend.
| Measure | 1991–2000 | 2016–2025 | Change |
|---|---|---|---|
| Hot days · ≥35°C (95°F) | 0.0 | 0.1 | +0.1 |
| Humid-heat days · heat index ≥103°F (39.4°C) | 0.1 | 0.3 | +0.2 |
| Warm nights · ≥24°C (75.2°F) | 0.0 | 0.0 | 0.0 |
| Heavy-rain days · ≥50 mm (≈2 in) | 0.2 | 0.2 | 0.0 |
| Annual maximum daily precipitation · mm | 37.9 | 38.8 | +0.9 |
- Counts are average days per year. A grid-cell zero does not mean the county had no such events.
- Warm nights count days whose daily minimum reaches 24°C (75.2°F). They do not count nighttime hours.
- Rain thresholds use daily precipitation, including snow water equivalent. The last row averages ten annual daily maxima, not the decade’s largest event.
- NASA days use local solar time.
- Humid-heat days reach a maximum hourly NOAA heat index of 103°F (39.4°C), the shade-based “Danger” band. Copernicus (ECMWF) reanalysis supplies hourly temperature and dew point; days use local clock time.
Hot-day cross-check: NOAA’s county-average daily maximum temperature gives 0.0 → 0.2 hot days a year (+0.2); NASA gives 0.0 → 0.1 (+0.1). Both series show an increase, with different counts and change sizes. The footprints differ, so agreement does not validate either count. Warm nights and precipitation were not cross-checked. Humid-heat row: Copernicus (ECMWF) reanalysis. It uses a different regional grid from the NASA measures.
No statistical significance, causal attribution or future trend is established. These two ten-year samples do not alter, explain or validate the FEMA ratings above.
Climate data: NASA · Population context: US Census Bureau · Hot-day cross-check: NOAA county climate records · Humid heat: Copernicus (ECMWF). Method, sources and limitations · Climate JSON · Data credits.
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direction"}}How does El Niño affect Chittenden County winters?
NOAA gives 100% El Niño odds for DJF 2026–27 (issued 2026-10-08); the supporting outlook issued 2026-10-19 gives 100%. These describe Pacific conditions, not local flood odds. In 6 of 9 past strong El Niño winters, Chittenden County was wetter than normal; median rainfall was 109% of normal.
| Winter | ONI | Rain | Temp. | Heavy days | Claims |
|---|---|---|---|---|---|
| 1957–58 | 1.7 | 138% | +2.2°F | 0 | — |
| 1965–66 | 1.6 | 80% | +1.7°F | 1 | — |
| 1972–73 | 1.8 | 109% | +0.3°F | 0 | — |
| 1982–83 | 2.1 | 89% | +3.6°F | 1 | 0 |
| 1991–92 | 1.5 | 89% | −1.5°F | 0 | 0 |
| 1997–98 | 2.4 | 131% | +3.3°F | 2 | 1 (#4) |
| 2009–10 | 1.5 | 108% | +1.1°F | 2 | 0 |
| 2015–16 | 2.6 | 122% | +5.7°F | 1 | 0 |
| 2023–24 | 2.0 | 115% | +5.8°F | 2 | 7 (#2) |
Rain is the winter total as a percent of the average of the 30 winters from 1990–91 to 2019–20 (8.1 inches). Temperature is compared with this county’s own straight-line winter trend from 1951–52 to 2024–25 (+0.7°F per decade), so long-term warming is not counted as an El Niño effect. Heavy days have 1 inch (25.4 mm) or more of county-average rain; the 1990–91 to 2019–20 winter normal is 0.7 days. A strong El Niño winter has an ONI (Oceanic Niño Index) peak of at least 1.5°C, taken as the largest of the NDJ, DJF and JFM values around the winter.
Flood claims are National Flood Insurance Program claims with a date of loss from December to February. The program’s open data start in 1978, so earlier winters show —. The rank compares each winter with all 47 winters from 1978–79 to 2024–25 (#1 is the most claims; no rank is shown for 0 claims). The median winter had 0 claims; 2 of 6 strong winters in the data were above it. Insured exposure grew over time, so counts are not comparable across decades.
Four checks for property teams
- Check flood deductibles and sub-limits. Read how the policy words “Flood” and “Named Storm”; one law firm reports insurers applying lower flood sub-limits and higher flood deductibles to hurricane losses. Source: Pillsbury Winthrop, 2013.
- Buy early. There is typically a 30-day waiting period for a National Flood Insurance Program policy to go into effect, with exceptions such as a policy required by a government-backed lender. Source: FEMA.
- Raise critical equipment. FEMA advises raising mechanical, electrical and plumbing systems to avoid flood damage, and moving critical equipment to a floor above the flood level. Source: FEMA.
- Ask tenants to move valuables up. FEMA emergency guidance lists moving valuables to higher levels as a step before a flood. Source: FEMA.
Past tendency is not a forecast. Each winter is one event, county averages hide local differences, and a strong El Niño does not guarantee a wet or dry winter. This is not a property-level finding.
Sources: NOAA county climate records and Pacific climate assessments; FEMA National Flood Insurance Program claims. Method and limits · El Niño 2026–27.
What are the modeled losses by hazard?
Among the reviewed hazards, riverine flood has the largest modeled annual loss at $28,797,704. Rating categories and dollar totals answer different questions.
Chittenden County’s modeled loss across all hazards is $40,136,955 per year. The FEMA National Risk Index ranks the hazards below by modeled loss, not rating category.
| Hazard | Total loss ($/yr) | Of which buildings ($/yr) | Observation window |
|---|---|---|---|
| All hazards (composite) | $40,136,955 | $32,558,646 | 1996-2023 |
| Riverine flooding | $28,797,704 | $28,508,887 | 1996-2023 |
| Earthquake | $2,147,955 | $1,833,011 | 1996-2023 |
| Heat wave | $1,797,421 | Not published | 2005-2024 |
| Tornado | $846,921 | $232,690 | 1950-2023 |
| Hurricane | $661,061 | $606,338 | 1851-2024 |
| Wildfire | $18,585 | $16,249 | 1996-2023 |
| Coastal flooding | Not available | Not available | 1996-2023 |
These modeled county totals do not estimate property losses, insurance inputs or forecasts. Do not multiply them by location counts.
What is exposed in Chittenden County?
Population and asset values show the scale behind county losses. These county totals are exposure measures, not loss figures.
| Measure | Value | Observation window |
|---|---|---|
| Resident population | 168,162 | 2020-2020 |
| Building replacement value | $40,414,880,347 | 2020-2020 |
| Agricultural market value | $56,100,811 | 2022-2022 |
What do vulnerability and resilience show?
These relative rankings describe susceptibility to hazard impacts and capacity to recover. They measure no individual asset or outcome.
| Measure | Score | Observation window |
|---|---|---|
| Social vulnerability index | 10.6 | 2020-2020 |
| Community resilience index | 94.3 | 2020-2020 |
How do I keep this comparison in my working file?
Download the county records as Excel or CSV. The proposed six-sheet report organizes a supplied shortlist, county evidence and unresolved rows after coverage confirmation.
How should I use this page?
Compare county hazards and loss amounts to form a research shortlist. Check exposure and resilience to judge a market’s loss scale. Building flood zones, condition, insurance, future loss and suitability need separate evidence. Keep the FIPS, metric name, unit and observation window in your workbook.
What needs another source?
A map question needs a verified location and official map evidence. Read the county rating versus flood-zone guide before making a location request.
What else should I know about Chittenden County?
Is this a property report?
No. These 27 reviewed FEMA metrics describe the county; property screening remains a separate, unbuilt workflow.
Why is a field not a number?
Riverine flooding in Chittenden County is Relatively Moderate. Hazard ratings are categories; loss and exposure are numbers. We preserve both without averaging categories into a score.
What do the dollar loss figures show?
FEMA models $40,136,955 in Expected Annual Loss (EAL) for Chittenden County. The figures show financial scale; see the limits beside the loss table.
What does “Not Applicable” or “No Rating” mean?
Neither is an ordered rating for that county and hazard. Neither means low risk or becomes zero.
How can I keep this record?
Use the FIPS 50007, the metric name, its unit and its observation window in the downloadable sample.
How does Chittenden County compare?
Compare the pilot counties using the same source fields in the comparison tool. County size and exposure affect loss totals. No state rank is available from this pilot sample. Open the interactive comparison to inspect individual measures.
How can I use this data?
Download the sample to keep the source fields in your workbook.
See pricing to review the scope of paid work.
Review data access for coverage and format discussions.
Read the El Niño hub for the shared winter method and outlook context.
What are the sources and limits?
FEMA supplies county hazard ratings and modeled loss. NOAA supplies winter climate context. NASA supplies regional climate measures; Copernicus/ECMWF supplies humid heat. The US Census Bureau supplies geographic context. Each table retains periods and units. Read the methodology. County evidence cannot establish building condition, insurance cost, flood-zone status or future damage.