Power Outage Risk in Hawaii

Hawaii's outage planning is shaped by island continuity: refrigeration, communications, medical support, and portable cooling matter quickly once a local outage stretches beyond the first day.

Honolulu County alone accounts for 4,497 electricity-dependent Medicare beneficiaries, while Hawaii County leads the state's NOAA event record, which makes Hawaii's practical outage case broader than either wildfire alone or hurricane season alone.

22 federal declarations in 10 years, with Hawaii and Honolulu as the strongest BPI intersections of storm frequency and medical-device density (2014-2023)

FEMA National Risk Index (NRI)

97.4 / 100

Relatively High

FEMA Declarations (2014-2023)

22 Major incidents

Highest Risk Window

Multi-season

Mixed Island Storm, Flood, and Wildfire Outage Risk

JanJunDec

What drives outage risk in Hawaii

Wildfire 98.2

FEMA Decl. 8

Hurricane 71.7

FEMA Decl. 4

Winter Weather 0.4

FEMA Decl. —

Severe Storm Not scored by NRI

FEMA Decl. 3

Why Hawaii is different

A hurricane-only description is too narrow for Hawaii's actual statewide data. The National Risk Index is led by riverine flooding, wildfire, and lightning, while NOAA's statewide event record is led by flash flood, high wind, and strong wind rather than only tropical systems.

The county layer supports that broader outage picture. Hawaii and Honolulu are the top public BPI counties, and HHS emPOWER counts 6,748 electricity-dependent Medicare beneficiaries statewide with Honolulu (4,497) far ahead of Hawaii (1,193), Maui (756), and Kauai (302). That creates a very practical refrigeration, communications, medical-support, and air-circulation case for both the urban and island-wide continuity problem.

The federal declaration mix is diverse: fire, hurricane, severe storm, flood, volcanic eruption, and landslide declarations all appear in the 2014-2023 window. One of the verified severe-storm or flood declarations fits Hawaii's practical outage problem better because it reflects island continuity across multiple hazards and counties.

Notable Recent Events

Hawaii Severe Storms, Flooding, and Landslides (2022)

FEMA DR-4639 — severe storms, flooding, and landslides in Hawaii from December 2021, declared in February 2022; the most recent verified severe-storm or flood declaration in the 2014-2023 window and a strong fit for Hawaii's practical outage mix across counties and hazard types.

Source: FEMA DR-4639

Evidence trail

State source notes

These notes trace the editorial claims above back to FEMA, DOE, utility, or other cited records.

5 notes

1 OpenFEMA API

FEMA declaration count (22) from OpenFEMA API, deduplicated by disaster number, DR/EM/FM types, 2014-2023; Hawaii's mix in this window includes Fire (8), Hurricane (4), Severe Storm (3), Flood (2), Volcanic Eruption (2), Mud/Landslide (1), and Biological (2).
2 FEMA NRI county layer

NRI composite score (97.4) from FEMA NRI county layer, population-weighted to state level; top modeled hazards are Riverine Flooding, Wildfire, and Lightning.
3 NOAA Storm Events 2005-2024

NOAA outage-relevant event mix is led by Flash Flood (444), High Wind (190), Strong Wind (162), Flood (32), and Thunderstorm Wind (20), with Hawaii, Honolulu, Kauai, and Maui leading county counts.
4 HHS emPOWER + GeneratorChecker BPI review

HHS emPOWER counts 6,748 electricity-dependent Medicare beneficiaries statewide; Honolulu (4,497), Hawaii (1,193), Maui (756), and Kauai (302) are the largest county totals. Hawaii and Honolulu are the top BPI counties in the GeneratorChecker cross-signal layer.
5 FEMA disaster records

Verified non-fire Hawaii options in the 2014-2023 window include DR-4365, DR-4549, DR-4604, and DR-4639. DR-4639 is used here as the most recent severe-storm or flood declaration and a better statewide fit than a hurricane, wildfire, or volcanic anchor.

Structured FEMA NRI, HHS emPOWER, NOAA Storm Events, and EIA methodology is documented separately on the methodology page.

NRI's top modeled hazards are Riverine Flooding, Wildfire, and Lightning, while NOAA's outage-relevant record is led by Flash Flood, High Wind, Strong Wind, Flood, and Thunderstorm Wind events..

Historical Storm Patterns in Hawaii

NOAA storm-event records filtered to outage-relevant event types for Hawaii. Counts reflect historical storm-event assignments, not confirmed utility outages.

Official data GeneratorChecker analysis

Analysis window

2005-01 to 2024-12

Included storm-event records

883

Source as of

2026-03

Included exact NOAA event types for Hawaii: Thunderstorm Wind, Tornado, High Wind, Strong Wind, Flash Flood, Flood, Hurricane (Typhoon), Tropical Storm, Tropical Depression, Storm Surge/Tide.

Hazard seasonality

In this filtered NOAA record set for Hawaii, Feb has the highest monthly count (162 records) , and Flash Flood is the leading event type. This chart shows frequency in NOAA records, not how severe a specific outage may be.

Sorted Jan–Dec

Jan 101

Feb 162

Mar 150

Apr 43

May 35

Jun 9

Jul 26

Aug 68

Sep 38

Oct 37

Nov 61

Dec 153

Top outage-relevant event types

1. Flash Flood 444
2. High Wind 190

18 events were not mapped to a county ranking.
3. Strong Wind 162

86 events were not mapped to a county ranking.
4. Flood 32
5. Thunderstorm Wind 20
6. Tropical Storm 13

8 events were not mapped to a county ranking.

Counties with highest historical outage-relevant storm event frequency

1. HAWAII 241

44.0% of listed records were matched directly to this county.
2. HONOLULU 219

64.8% of listed records were matched directly to this county.
3. KAUAI 160

92.5% of listed records were matched directly to this county.
4. MAUI 141

78.0% of listed records were matched directly to this county.

Coverage and limitations

With the current Hawaii NWS county crosswalk, mapped forecast zones are effectively 1:1 with counties; unresolved legacy or coastal forecast zones fall into the excluded bucket.

Source notes NOAA Storm Events ↗

Direct county match

57.3%

Mapped from forecast zone

28.9%

Not assigned to county ranking

13.8%

Unresolved forecast zones

Forecast-zone events with no current NWS county crosswalk entry are excluded from county-level rankings.
Forecast-zone events are mapped with the current NWS county crosswalk, which may not exactly match historical zone boundaries across the full analysis window.
Counts reflect historical NOAA storm event records, not confirmed utility outage counts.
Marine event types remain excluded from this state contract even when coastal impacts may be operationally relevant.

Medical Outage Sensitivity in Hawaii

County-level HHS emPOWER counts for electricity-dependent Medicare beneficiaries in Hawaii.

Official data

6,748 Medicare beneficiaries in Hawaii have claims associated with electricity-dependent medical equipment. (HHS emPOWER, 2026-03)

County-level HHS emPOWER records for this state. Medicare enrollment data only. 5 counties are included in this state snapshot.

Counties by total count

1. Honolulu 4,497
2. Hawaii 1,193
3. Maui 756
4. Kauai 302
5. Kalawao 0

Counties by share of Medicare beneficiaries

Counties with at least 1,000 Medicare beneficiaries

1. Hawaii 2.2%
2. Honolulu 2.2%
3. Maui 2.1%
4. Kauai 1.7%

GeneratorChecker analysis

Source notes HHS emPOWER Map ↗

Counties with higher concentrations may face elevated community-level demand for backup power during outages. This does not indicate individual medical necessity.

CPAP battery backup guide Oxygen concentrator backup guide

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.

GeneratorChecker BPI BPI v1.0 · NOAA 2005-2024 · HHS emPOWER 2026-03

Backup Priority Index in Hawaii

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.

Official data GeneratorChecker analysis

BPI version

v1.0

Analysis window

2005-01 to 2024-12

Matched counties

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.

Top BPI counties in this state

Percentiles are computed within Hawaii only and are not comparable across states.

Source notes

1. HAWAII

County FIPS 15001

Storm frequency · Top 1% statewide Medical exposure · Top 20% statewide

At-risk Medicare count

1,193

Storm-event records

241

Direct NOAA county match

44.0%
2. HONOLULU

County FIPS 15003

Storm frequency · Top 20% statewide Medical exposure · Top 1% statewide

At-risk Medicare count

4,497

Storm-event records

219

Direct NOAA county match

64.8%

How to read the BPI

BPI qualifies a county only when both the NOAA outage-relevant storm signal and the HHS emPOWER medical-count signal are at or above the 80th percentile within the state.
The medical signal uses total county count of electricity-dependent Medicare beneficiaries, not the share of beneficiaries within each county.
Counties with weak direct NOAA county matching stay out of the public BPI list even when their storm percentile is high.
Percentiles are computed within each state only and are not comparable across states.
The BPI is a planning layer. It does not claim a forecast, a utility reliability score, or an individualized medical-risk assessment.

Size your backup for Hawaii

Use a 24-hour island continuity bundle as the baseline, then extend to 48 hours if the household needs to bridge a longer local outage without assuming a hurricane-shelter loadout.

24-hour island continuity

Primary Hawaii scenario: local storm, flood, or wildfire disruption interrupts power while refrigeration, communications, medical support, and portable air circulation remain critical.

French Door Refrigerator Box Fan (20-inch) CPAP Machine WiFi Router

Load

421W

Target

24h

Minimum

16,700 Wh

Built for the core household continuity case across the islands. This models portable cooling support, not whole-home air conditioning.

Size this scenario in calculator

48-hour island continuity

Extended Hawaii scenario: a longer local outage stretches into a second day while the same core household loads stay online.

French Door Refrigerator Box Fan (20-inch) CPAP Machine WiFi Router

Load

421W

Target

48h

Minimum

33,300 Wh

Extends duration rather than adding more devices. This intentionally avoids a Gulf-style hurricane-shelter bundle.

Size this scenario in calculator

Critical Note: No single portable power station in our database covers the full 24-hour baseline at this load (16,700 Wh target vs. 6,144 Wh max in our current database). Use solar recharge, load rotation, or expandable systems for longer events.

Common mistakes in Hawaii

Treating Hawaii like a Gulf-style hurricane problem when flood, wind, and wildfire all appear in the statewide record.
Treating Hawaii as a wildfire-only state when Honolulu and Hawaii counties still need refrigeration and medical continuity through a broader set of outages.
Choosing a dramatic single-hazard anchor that does not fit Hawaii's broader statewide outage mix.

Top mistake: Sizing around a single hazard narrative instead of the practical refrigerator, fan, router, and medical-device loads that matter across the islands.

Go Deeper

Best Portable Power Stations for Home Backup (2026): Outage-Ready Picks

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.

Battery Backup for Medical Devices: Power Outage Planning Checklist

From CPAP to oxygen concentrators, here is a practical checklist for keeping medical equipment running during power outages. Includes sizing math and emergency contacts.

Solar Panels for Portable Power Stations: The Complete Compatibility Guide

Not all solar panels work with all power stations. MPPT voltage ranges, connector types, and real-world charge times from our database of 20 panels and 33 stations.

Data Sources & Methodology

NRI risk details

Composite score: 97.4 / 100

Rating: Relatively High

Top modeled hazards: Riverine Flooding, Wildfire, Lightning

Hurricane score: 71.7

Winter Weather score: 0.4

Wildfire score: 98.2

FEMA declaration breakdown

Total (2014-2023): 22

Most recent: 2023-08-10 Fire

Type	Count
Fire	8
Hurricane	4
Severe Storm	3
Biological	2
Flood	2
Volcanic Eruption	2
Mud/Landslide	1

Sizing formula

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

Historical utility-reported and modeled data. Your experience may vary.

Frequently Asked Questions

How high is outage risk in Hawaii?

Hawaii has an NRI composite risk score of 97.4 (Relatively High), with 22 federal declarations from 2014 to 2023. NRI's top modeled hazards are Riverine Flooding, Wildfire, and Lightning, while NOAA's outage-relevant record is led by Flash Flood, High Wind, Strong Wind, Flood, and Thunderstorm Wind events..

What backup size should I target in Hawaii?

For the primary scenario on this page (24-hour island continuity), the estimated minimum is 16,700 Wh for a 24-hour target. Refine this in the calculator with your actual devices.

Why do modeled risk and declaration history sometimes differ?

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.

What are the most common outage-planning mistakes in Hawaii?

Sizing around a single hazard narrative instead of the practical refrigerator, fan, router, and medical-device loads that matter across the islands. See the common mistakes section above for more state-specific pitfalls.

Why do Hawaii outages require different planning than mainland outages?

Hawaii outages can be harder to bridge because recovery is not backed by simple overland resupply, and county-level disruption is already geographically isolated. Once a local outage stretches beyond the first day, refrigeration, communications, medical support, and recharge planning tighten quickly.