Terrain-driven flooding and winter conditions can isolate rural households even after utility restoration begins.
In Vermont, the grid can recover before the roads do, so backup planning is about staying self-sufficient for several days until isolated towns can be reached again.
Lower Composite Risk, High Consequence Events
Vermont's outage risk is defined less by the grid itself than by the geography surrounding it. Green Mountain Power, the state's largest utility, serves roughly three-quarters of Vermont's customers. When Tropical Storm Irene hit in August 2011, the storm produced up to 11 inches of rain in 24 hours across the Green Mountains.
Rivers turned into floodways that destroyed over 500 miles of roadway and damaged or destroyed approximately 1,200 bridges and culverts. Thirteen communities were completely cut off, with no passable roads in or out. The National Weather Service documented nearly 50,000 power outages statewide. But the electrical grid was not the primary failure point. The real crisis was physical isolation: fuel deliveries, supply trucks, and utility crews could not reach stranded towns for days. Total costs from that single storm reached roughly 603 million dollars in federal outlays, 153 million in state and local expenses, and 63 million in insurance claims.
For backup sizing, Vermont's pattern inverts the usual calculus. The grid tends to recover fast, but road access does not. A portable station in a Vermont river valley needs enough stored capacity to operate independently until roads reopen, because resupply may not arrive for days.
Federal disaster declaration for severe storms and flooding across Vermont, the most significant flooding event since Tropical Storm Irene.
Source: FEMA DR-4720Evidence trail
These notes trace the editorial claims above back to FEMA, DOE, utility, or other cited records.
FEMA declaration count (17) from OpenFEMA API, deduplicated by disaster number, DR/EM/FM types, 2014-2023.
NRI composite score (47.8) from FEMA NRI county layer, population-weighted to state level.
July 2023 Flooding DR-4720 from FEMA disaster declaration records.
Tropical Storm Irene VT impact (11 in. rain/24h, 500 mi road, 1,200 bridges/culverts, 50K outages): NWS Flooding in Vermont, Irene section (2011-09).
Community isolation (13 towns cut off) and costs ($603M federal, $153M state/local, $63M insurance): Flood Ready Vermont, Rising Danger — The Cost of Flooding (2014-10).
Structured FEMA NRI, HHS emPOWER, NOAA Storm Events, and EIA methodology is documented separately on the methodology page.
FEMA National Risk Index (NRI) composite score of 47.8 sits alongside documented flood and winter-storm outage history.
NOAA storm-event records filtered to outage-relevant event types for Vermont. Counts reflect historical storm-event assignments, not confirmed utility outages.
Analysis window
2005-01 to 2024-12
Included storm-event records
4,346
Source as of
2026-03
Included exact NOAA event types for Vermont: Hurricane (Typhoon), Tropical Storm, Tropical Depression, Thunderstorm Wind, Tornado, High Wind, Strong Wind, Flash Flood, Flood, Winter Storm, Ice Storm, Freezing Rain, Heavy Snow, Blizzard.
In this filtered NOAA record set for Vermont, Jul has the highest monthly count (732 records) , and Thunderstorm Wind is the leading event type. This chart shows frequency in NOAA records, not how severe a specific outage may be.
82 events were not mapped to a county ranking.
24 events were not mapped to a county ranking.
3 events were not mapped to a county ranking.
3 events were not mapped to a county ranking.
51.2% of listed records were matched directly to this county.
45.2% of listed records were matched directly to this county.
44.4% of listed records were matched directly to this county.
43.0% of listed records were matched directly to this county.
32.0% of listed records were matched directly to this county.
47.1% of listed records were matched directly to this county.
With the current Vermont NWS county crosswalk, mapped forecast zones are effectively 1:1 with counties; a small number of unresolved inland forecast zones remain excluded from county rankings.
Direct county match
46.0%
Mapped from forecast zone
51.3%
Not assigned to county ranking
2.7%
Unresolved forecast zones
1
County-level HHS emPOWER counts for electricity-dependent Medicare beneficiaries in Vermont.
5,750 Medicare beneficiaries in Vermont have claims associated with electricity-dependent medical equipment. (HHS emPOWER, 2026-03)
County-level HHS emPOWER records for this state. Medicare enrollment data only. 14 counties are included in this state snapshot.
Counties with higher concentrations may face elevated community-level demand for backup power during outages. This does not indicate individual medical necessity.
Limitations: Reflects Medicare beneficiaries with claims associated with electricity-dependent medical equipment. Does not capture non-Medicare or uninsured populations. HHS masks cells from 1 to 10 as 11.
The GeneratorChecker Backup Priority Index is a county shortlist for backup planning, combining historically frequent outage-relevant storm activity with larger county counts of electricity-dependent Medicare beneficiaries. It is planning context, not a forecast or an outage guarantee.
BPI version
v1.0
Analysis window
2005-01 to 2024-12
Matched counties
14
Counties qualify for the public BPI only when both signals land at or above the 80th percentile within the state. The shortlist excludes low-base medical counties and counties with less than 30% direct NOAA county matching.
Qualifying counties shown on the page: 2.
Percentiles are computed within Vermont only and are not comparable across states.
1. CHITTENDEN
County FIPS 50007
At-risk Medicare count
962
Storm-event records
492
Direct NOAA county match
51.2%
2. RUTLAND
County FIPS 50021
At-risk Medicare count
767
Storm-event records
435
Direct NOAA county match
44.4%
State-level utility structure from official EIA Form 861 data, shown as planning context alongside the weather and medical layers.
Data year
2024
Utilities in scope
3
Residential customers represented
280,500
93.6% of in-scope residential customers in Vermont are served by utilities that report complete annual SAIDI and SAIFI pairs to EIA for 2024, excluding major event days.
GeneratorChecker does not blend statewide SAIDI or SAIFI values across IEEE and Other Standard reporters in this public layer.
This block identifies the utility structure behind the state, but it does not score your local grid reliability.
IOU
Cooperative
Municipal
Even in lower-risk states, size for essentials first and keep a realistic winter outage reserve.
Heating-system support, communications, and medical continuity during a winter outage.
Load
1189W
Target
24h
Minimum
46,900 Wh
This scenario assumes your home uses a gas furnace or boiler that still depends on blower power. Portable power stations are not a substitute for electric resistance heating.
Size this scenario in calculatorAdd refrigeration to preserve food during a multi-day grid outage while keeping heating-system support online.
Load
1396W
Target
48h
Minimum
110,100 Wh
Consider expandable systems or solar for events beyond 48 hours.
Size this scenario in calculatorCritical Note: No single portable power station in our database covers the full 24-hour baseline at this load (46,900 Wh target vs. 6,144 Wh max in our current database). Use solar recharge, load rotation, or expandable systems for longer events.
Treating lower statewide risk as no-need for backup while winter and terrain-driven disruptions remain possible.
Ignoring cold-weather runtime losses and increased essential-load importance.
Failing to plan for communication continuity in rural or low-density service areas.
A 1,500W space heater drains a power station in 1-2 hours. Here's the honest math on battery-powered heating, plus smarter alternatives that actually work.
For home backup, you need surge capacity for fridge compressors and enough Wh for multi-day outages. Here are the best options from our database of 33 stations.
From CPAP to oxygen concentrators, here is a practical checklist for keeping medical equipment running during power outages. Includes sizing math and emergency contacts.
Composite score: 47.8 / 100
Rating: Relatively Low
Top modeled hazards: Landslide, Winter Weather, Hurricane
Hurricane score: 67.3
Winter Weather score: 68.3
Wildfire score: 21.0
Total (2014-2023): 17
Most recent: 2023-10-06 Flood
| Type | Count |
|---|---|
| Severe Storm | 7 |
| Flood | 6 |
| Biological | 2 |
| Hurricane | 1 |
| Severe Ice Storm | 1 |
Required Wh = (Total Load W × Target Hours / Inverter Derate) × Safety Factor
Inverter derate: 0.70 (30% real-world loss)
Safety factor: 1.15
Rounding: Up to nearest 100 Wh
Vermont has an NRI composite risk score of 47.8 (Relatively Low), with 17 federal declarations from 2014 to 2023. FEMA National Risk Index (NRI) composite score of 47.8 sits alongside documented flood and winter-storm outage history.
For the primary scenario on this page (24-hour heating-support essential), the estimated minimum is 46,900 Wh for a 24-hour target. Refine this in the calculator with your actual devices.
NRI is a modeled risk index based on hazard exposure, vulnerability, and expected loss. FEMA declarations reflect federally declared incidents. They answer different questions — use both signals together for planning.
Skipping preparedness entirely because risk appears lower, instead of matching capacity to critical needs. See the common mistakes section above for more state-specific pitfalls.
