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What causes power outages, and how long do they usually last?

Updated

General information, not a substitute for the advice of an attorney.

Short answer: Storms cause most of the hours Americans spend without power. In 2024, the latest year EIA has reported, the average US customer experienced about 11 hours of interruptions, roughly twice the prior decade's average; nearly nine of those hours came from major events, and three hurricanes alone (Beryl, Helene, and Milton) accounted for 80% of the hours lost. Strip out major events and routine outages run about two hours a year (EIA, December 1, 2025).

How EIA measures it

Utilities report reliability data to EIA on form EIA-861. The two figures that matter most are total minutes (or hours) of interruption per customer and the number of interruptions per customer, each reported with and without "major events" such as hurricanes or other storms. In 2024 the US average was 1.5 interruptions per customer (EIA).

The 2024 numbers

  • Average total interruption time: about 11 hours per customer in 2024, versus an average of nearly four hours per year from major events in 2014 through 2023 (EIA).
  • Major events: nearly nine hours in 2024. Hurricanes Beryl, Helene, and Milton accounted for 80% of hours without electricity (EIA).
  • Without major events: interruptions routinely average about two hours per year (EIA).
  • Worst state: South Carolina, nearly 53 hours in 2024. Best: Arizona, South Dakota, North Dakota, and Massachusetts, each under two hours (EIA).
  • Most frequent: Hawaii, 4.4 interruptions per customer. South Dakota, Maryland, Illinois, and Massachusetts had fewer than one (EIA).

What this means for a typical outage

The averages blend two very different things: short, frequent interruptions from equipment faults, vehicles, animals, and local weather, which add up to about two hours a year, and rare, long outages after major storms, which can run for days and dominate the yearly total. EIA's article names only hurricanes and other storms as 2024's major-event causes; it does not break out wildfires, heat, or cold, so this page does not either (EIA).

National averages hide a lot. The same storm season produced 53 hours in South Carolina and under two in Arizona. For your own area, the outage history by county and ZIP page on this site is built from the same EIA-861 reliability file (2013 through 2024) and shows the local averages with and without major events.

See outage history by county and ZIP, what ERCOT is, and substation vs. transmission line.

General information from the sources linked above, not legal, tax, or financial advice.

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