Chittenden County, VT climate risk

Chittenden County in the state and national rankings

National placement for Chittenden County is #652 of 3,232, with an expected annual loss estimate of about $40.1 million. The county ranks #1 of 14 in Vermont and accounts for 18.1% of state loss. This $40.1 million estimate is a long-run modeled annual average, not a forecast for a particular year. Lancaster County, SC ranks immediately above it, with about $40.1 million in modeled annual loss. The next lower national total is about $40.1 million, in Alexandria City, VA. The nearest lower state total is about $25.1 million, recorded for Windsor County, VT. The dollar gap is about $15.0 million; that county accounts for 11.4% of statewide modeled loss.

Vermont county comparisons

Chittenden County hazard estimates

Riverine Flood

FEMA models about $28.8 million in expected annual loss from riverine flooding, placing the county #419 of 3,232 nationally. At 71.7% of the county’s modeled loss, the hazard places #1 of 14 statewide; FEMA assigns a Relatively Moderate rating; the same rating for riverine flooding covers 2 Vermont counties and 639 across the US.

Earthquake

The national loss rank for earthquakes is #611 of 3,232, based on about $2.1 million in modeled expected annual loss. In Vermont, this estimate ranks #1 of 14 and represents 5.4% of the county’s modeled loss; FEMA assigns a Relatively Low rating; the same rating for earthquakes covers 2 Vermont counties and 962 across the US.

Heat Wave

FEMA models about $1.8 million in expected annual loss from heat waves, placing the county #495 of 3,202 nationally. This hazard makes up 4.5% of the total; FEMA assigns a Relatively Low rating, and its loss ranks #1 of 14 in Vermont; for heat waves, 5 state counties and 1,246 US counties share that label.

Cold Wave

With about $1.6 million in modeled expected annual loss from cold waves, the county ranks #1,109 of 3,232 in the national comparison. Its 4.0% share of total loss comes with a state loss rank of #3 of 14; FEMA assigns a Relatively Low rating; the Relatively Low label covers 11 state counties and 1,307 nationally for cold waves.

Lightning

The national loss rank for lightning is #248 of 3,222, based on about $1.4 million in modeled expected annual loss. At 3.5% of the county’s modeled loss, the hazard places #1 of 14 statewide; FEMA assigns a Relatively High rating, matching 461 US counties, including 1 in Vermont, for this hazard.

Strong Wind

With about $1.2 million in modeled expected annual loss from strong wind, the county ranks #683 of 3,225 in the national comparison. At 3.0% of the county’s modeled loss, the hazard places #1 of 14 statewide; FEMA assigns a Relatively Moderate rating, matching 1,011 US counties, including 2 in Vermont, for this hazard.

Between riverine flooding and earthquakes, the modeled dollar gap is about $26.6 million; their shares differ by 66.4 percentage points. The loss estimate for earthquakes exceeds heat waves by about $351,000, equivalent to 0.9 percentage points of total loss. About $210,000 separates heat waves from cold waves in the local estimates, equivalent to 0.5 percentage points of county loss. The loss estimate for cold waves exceeds lightning by about $169,000, equivalent to 0.4 percentage points of total loss. The loss estimate for lightning exceeds strong wind by about $195,000, equivalent to 0.5 percentage points of total loss.

Population and recorded values

Chittenden County covers about 626 square miles, with 168,162 residents in FEMA data. For building value, the source records about $40.41 billion. The recorded agricultural value is about $56.1 million. Total modeled loss averages about $239 per resident annually, compared with about $344 statewide. The county holds 26.2% of the state population, compared with 18.1% of modeled loss. Buildings account for 23.2% of recorded Vermont building value. The county holds density position 1 of 14 in Vermont, using FEMA’s recorded population and area. The population-to-area ratio is about 269 residents per square mile; statewide it is about 66. At 168,162 residents, the county compares with the Vermont county median of about 37,330. Of FEMA’s US population, 0.1% lives here, alongside 0.0% of national modeled annual loss. The county’s about $239 per resident compares with about $459 nationally in modeled annual loss. About $37.0 million of annual loss falls within the six leading hazards, accounting for 92.1% of the total. Other hazards account for the remaining 7.9% of modeled loss, about $3.2 million. The county’s number 7 hazard by dollar loss is tornadoes: about $847,000, with a state rank of #2 of 14. Its national loss rank is #1,824 of 3,225, and it represents 2.1% of the county’s modeled loss. The county’s number 8 hazard by dollar loss is hurricanes: about $661,000, with a state rank of #6 of 14. With 1.6% of county loss, this hazard has national placement #735 of 2,485.

FEMA labels and risk score

Chittenden County has a FEMA risk index score of about 63.9, ranking #1,136 of 3,144 nationally. FEMA labels risk index as Relatively Low, matching 6 county records across Vermont. For expected annual loss, FEMA assigns Relatively Low; 6 counties in Vermont have that label. The social vulnerability rating is Very Low, a label shared by 8 of 14 Vermont counties. The community resilience rating is Very High, a label shared by 6 of 14 Vermont counties. Within Vermont, the risk score places #1 of 14 and the dollar loss places #1 of 14. Within Vermont, 6 counties share both labels: Very Low vulnerability and Very High resilience. This county accounts for 39.6% of that group’s annual loss, while the group accounts for 45.8% across Vermont. On the state risk-score list, Windsor County, VT sits immediately below, scoring about 61.6 and ranking #2 of 14. For that neighboring score, the risk index category is Relatively Low, and the county’s state loss share is 11.4%. Nationally, 625 counties carry the same Very Low social vulnerability label, covering 23.7% of FEMA’s recorded population. FEMA lists 629 county records with Very High community resilience; together they contain 27.2% of its US population total. Across the county’s hazard ratings, 1 carry Relatively High: lightning. FEMA assigns Relatively Moderate to 5 hazards here, covering avalanches, ice storms, riverine flooding, strong wind, winter weather. The county’s Relatively Low group contains 6 hazards: cold waves, earthquakes, heat waves, hurricanes, landslides, tornadoes. Across the county’s hazard ratings, 2 carry Very Low: hail, wildfires.