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What to do in a 72-hour power outage, hour by hour

This guide lays out three days without power, hour by hour: the safety checks to make at the start, then food and water, heat and cold, generators, phones and information. Each step comes from official guidance.

By The OffGridOne team Placeholder, waiting on the owner:founder names. Last updated

Keep the fridge and freezer shut, use battery flashlights instead of candles, and run any generator outdoors, at least 20 feet from the house. Then follow the clock below. Food is on the shortest timer: about four hours for a fridge, 48 hours for a full freezer.

Official pages do not use the phrase "72 hours". Ready.gov says you may need to get by on your own for "several days" (Ready.gov, Build A Kit). The Red Cross asks for a 3-day kit to carry and two weeks of supplies at home (Red Cross, Kit). This guide uses three days as its frame. A printable version is on the 72-hour power outage checklist page.

What should I do first when the power goes out?

Keep the fridge and freezer doors closed, switch to battery flashlights, and unplug sensitive electronics. If the weather is extreme or anyone relies on powered medical gear, decide early whether to stay or move to a place with power.

  1. Keep freezers and refrigerators closed. Every opening lets cold air out (Ready.gov, Power Outages).
  2. Disconnect appliances and electronics. This avoids damage from electrical surges (Ready.gov, Power Outages).
  3. Use battery-powered flashlights and lanterns, not candles. This lowers the fire risk (CDC, Power Outage).
  4. Tell your electric company and fire department if someone uses a medical device that needs power (FDA, Medical Devices).
  5. Ask local officials where heating or cooling locations are open (Ready.gov, Power Outages).

How long do power outages usually last?

Most are short. Without major events, the average U.S. customer lost power for about two hours a year. Big storms change that. In 2024 the average was about 11 hours, and major events caused 80% of those hours.

The U.S. Energy Information Administration (EIA) says interruptions not caused by major events "routinely average about two hours per year" (EIA). Its 2025 table shows 269.2 minutes (4.5 hours) per customer with major events counted, and 125.3 minutes without them (EIA, Electric Power Annual).

An average hides the long ones. In 2024, customers in South Carolina averaged nearly 53 hours without power (EIA). That is why a three-day plan makes sense even though most outages are brief.

What is the hour by hour plan?

Right away, close the doors and light the house safely. At 4 hours a fridge hits its limit. At 24 hours a half-full freezer does. At 48 hours a full freezer does. By day 3, water, medicine and warmth matter most.

WhenWhat to do
Right awayKeep fridge and freezer closed. Unplug electronics. Use flashlights, not candles. Generator outdoors only. (Ready.gov, Power Outages) (CDC, Power Outage)
4 hoursRefrigerated food reaches its limit. Move it to a cooler with ice, or throw it out. (CDC, Food Safety)
24 hoursA half-full freezer reaches its limit. Refrigerated medicine: discard unless the label says otherwise. (CDC, Food Safety) (CDC, Power Outage)
48 hoursA full freezer reaches its limit. (CDC, Food Safety)
Day 3Water is the limit to watch: the CDC says store at least 1 gallon per person per day for 3 days. Check your heat or cooling plan and phone power. (CDC, Water Supply)
Power returnsTurn off or disconnect appliances, because surges can follow. Check that medical device settings did not reset. (Ready.gov, Power Outages) (FDA, Medical Devices)

How long does food last without power?

A closed fridge keeps food safe for about 4 hours. A full freezer holds for about 48 hours, a half-full one for 24. After that, throw out perishable food. Never taste food to check it. When in doubt, throw it out.

The CDC says if doors stay closed, food stays safe up to 4 hours in a refrigerator, 48 hours in a full freezer and 24 hours in a half-full freezer (CDC, Food Safety). The FDA gives the same numbers (FDA, Food and Water).

  • At 4 hours, put meat, fish, cut fruits and vegetables, eggs, milk and leftovers in a cooler with ice or frozen gel packs. If you have no cold source, throw them out (CDC, Food Safety).
  • Frozen food that still has ice crystals, or is at 40°F or below, can be refrozen or cooked (CDC, Food Safety).
  • Eat fresh, perishable food first (Red Cross, Power Outage).

One note on a mismatch. Ready.gov says to discard food exposed to 40°F or higher for two hours or more (Ready.gov, Power Outages). The CDC counts four hours for a closed fridge. If unsure, use the shorter number.

How do I stay safe with heat, cold and a generator?

Never run a generator, grill or camp stove inside a home or garage. Keep a generator outdoors, at least 20 feet from windows, doors and vents. Do not heat a home with a gas oven. If it gets too hot or cold, go somewhere safer.

  • Place the generator outdoors, 20 feet or more from the house, with the exhaust pointed away (CPSC).
  • Put battery-powered or battery backup CO alarms on every level and outside sleeping areas (CPSC).
  • Know the signs: headache, dizziness, weakness, nausea, vomiting, sleepiness and confusion (CPSC).
  • Do not use a gas stove or oven to heat your home (Ready.gov, Power Outages).
  • Do not rely only on fans for heat. If conditions are too hot or too cold, stay with friends or go to a community shelter (CDC, Power Outage).

What about water, medicine and medical devices?

Store at least one gallon of water per person per day for three days. After a day without power, official guidance says to discard refrigerated medicine unless the label says otherwise. Ask your doctor or pharmacist ahead of time about medicine and powered devices.

  • Water. The CDC advises at least 1 gallon per person per day for 3 days, and a 2-week supply if possible (CDC, Water Supply). Water purification may not work fully when power is out (CDC, Power Outage).
  • If tap water is in doubt, use bottled water or boil clear water at a rolling boil for 1 minute (CDC, Safe Water). Above 5,000 feet, boil for 3 minutes (EPA, Water). Boiling does not remove fuel or toxic chemicals (CDC, Safe Water).
  • Medicine. The CDC says to throw away refrigerated medication after a day or more without power, unless the label says otherwise (CDC, Power Outage). The FDA says medicine that sustains life, such as insulin, may be used until you can get a new supply if no replacement is available. Call a pharmacist or provider (FDA, Medicine).
  • Powered devices. Read your device instructions to learn whether it can run on batteries or a generator. If a device keeps you alive, seek emergency services right away (FDA, Medical Devices).

How do I keep my phone and information going?

Charge devices before a storm, dim the screen and use low power mode. With no bars, turn the phone off or use airplane mode. Texts may go through when calls do not. Keep a battery or hand crank radio for news and alerts.

Ready.gov suggests a portable charger or power bank for outages (Ready.gov, Power Outages), and low power or airplane mode to save energy (Ready.gov, Get Tech Ready). The FCC says that with no signal bars, turning the phone off stops it draining while it hunts for a network (FCC, Emergency Tips). It also says texts may go through when a call does not (FCC, Emergency Tips).

There is a trade-off. A phone in airplane mode will not receive Wireless Emergency Alerts (FCC, Wireless Alerts). A battery or hand crank radio that gets NOAA Weather Radio is on the Ready.gov kit list (Ready.gov, Build A Kit).

Cell service can fade as an outage runs on. Two days after Hurricane Helene landfall, the FCC reported 1,079 of 1,452 cell sites out of service in the North Carolina disaster area. Power loss was the cause listed for 622 of them (FCC, Helene report). The FCC warns that a count of cell sites out does not always match what customers can use. Charging in a car? Keep it in a ventilated area, never a closed garage (FEMA, Communication Plan).

Sources

  1. Ready.gov (FEMA). Build A Kit. Published July 1, 2026. Checked November 9, 2026.
  2. American Red Cross. Survival Kit Supplies. Checked November 9, 2026.
  3. Ready.gov (FEMA). Power Outages. Published June 4, 2026. Checked November 9, 2026.
  4. Centers for Disease Control and Prevention. What to Do to Protect Yourself During a Power Outage. Published August 26, 2026. Checked November 9, 2026.
  5. U.S. Food and Drug Administration. FDA Offers Tips about Medical Devices and Natural Disasters. Published April 16, 2024. Checked November 9, 2026.
  6. U.S. Energy Information Administration. Hurricanes in 2024 led to the most hours without power in the United States in 10 years. Published December 1, 2025. Checked November 9, 2026.
  7. U.S. Energy Information Administration. Table 11.1: Reliability Metrics of U.S. Distribution System. Published October 21, 2026. Checked November 9, 2026.
  8. Centers for Disease Control and Prevention. Keep Food Safe After a Disaster or Emergency. Published November 24, 2025. Checked November 9, 2026.
  9. Centers for Disease Control and Prevention. How to Create an Emergency Water Supply. Published June 27, 2025. Checked November 9, 2026.
  10. U.S. Food and Drug Administration. Food and Water Safety During Power Outages and Floods. Published March 5, 2024. Checked November 9, 2026.
  11. American Red Cross. Power Outage Safety. Checked November 9, 2026.
  12. U.S. Consumer Product Safety Commission. Carbon Monoxide Information Center. Checked November 9, 2026.
  13. American Red Cross. Safe Generator Use. Checked November 9, 2026.
  14. Centers for Disease Control and Prevention. How to Make Water Safe in an Emergency. Published September 19, 2024. Checked November 9, 2026.
  15. U.S. Environmental Protection Agency. Emergency Disinfection of Drinking Water. Published February 24, 2026. Checked November 9, 2026.
  16. U.S. Food and Drug Administration. Safe Drug Use After a Natural Disaster. Published September 1, 2026. Checked November 9, 2026.
  17. Ready.gov (FEMA). Get Tech Ready. Published March 13, 2026. Checked November 9, 2026.
  18. Federal Communications Commission. Emergency Communications Tips. Published May 1, 2026. Checked November 9, 2026.
  19. Federal Communications Commission. Wireless Emergency Alerts (WEA). Checked November 9, 2026.
  20. Federal Communications Commission. Communications Status Report for Areas Impacted by Hurricane Helene, September 28, 2024. Published September 28, 2024. Checked November 9, 2026.
  21. FEMA. Create Your Family Emergency Communication Plan. Checked November 9, 2026.

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