How long do power outages last? What happened elsewhere
Short accounts of real events, from official reviews and first-party statements. Each fact names its source. Each event shows one thing for a household plan.
The short answer
It depends on the cause and on where you live. This page holds large events that have an official review or a first-party statement, not everyday local faults, and we give no average.
The ENTSO-E expert panel says that after the blackout of April 2025 the Portuguese system was back within 12 hours and the Spanish system within 16 hours. The Government of Ireland review of Storm Éowyn says that the last customers had power again 18 days after the storm.
Most homes had power again much sooner than the last ones. Ofgem, Great Britain's energy regulator, says that after Storm Arwen 82% of customers were reconnected within 24 hours, and that for nearly 4,000 customers the supply stayed off for more than a week. The Irish review says that almost 70% of customers had power again within the first 72 hours.
A time that a company gives for the power to come back can be wrong. In its review of Storm Arwen, Ofgem found that the restoration time given to 28% of customers was wrong by more than 24 hours. That is one event in one country.
The reviews and statements also show what stops with the power: tap water, mobile networks and card payments. Each event below gives its sources' own figures, and lists the sources.
The Iberian blackout: Spain and Portugal
Spain and Portugal, 28 April 2025
ENTSO-E, the body of Europe's grid operators, says that the power systems of mainland Spain and Portugal had a total blackout at 12:33 CEST on 28 April 2025. The ENTSO-E expert panel says that the Spanish system was fully restored within 16 hours and the Portuguese system within 12 hours. A European Central Bank staff article says that over 50 million people were affected and that some areas had power again only about 22 hours after the start. The same European Central Bank article says that digital payment systems failed, and that many card terminals and cash machines (ATMs) did not work for hours, while banknotes still worked.
What it shows. When the power and the phone networks stop, cards and cash machines can stop too, so a little cash at home can let you pay for essentials.
Sources for this event
- European Central Bank (staff article by Francesca Faella and Alejandro Zamora-Pérez), Keep calm and carry cash: lessons on the unique role of physical currency across four crises, European Central Bank (opens in a new tab). Page date: ECB Economic Bulletin, Issue 6/2025. Read 12 November 2026.
- European Network of Transmission System Operators for Electricity (ENTSO-E), 28 April 2025 Blackout, ENTSO-E (opens in a new tab). Page date: last updated 20 March 2026. Read 12 November 2026.
- ENTSO-E Expert Panel, Grid Incident in Spain and Portugal on 28 April 2025: Final Report, ENTSO-E expert panel (opens in a new tab). Page date: 20 March 2026. Read 12 November 2026 in the official PDF.
Storm Éowyn: Ireland
Ireland, 24 January 2025
The Government of Ireland review says that at the peak approximately 768,000 customers lost their electricity supply. The review says that almost 70% of customers had power again within the first 72 hours, and that the last customers waited 18 days. The review also says that over 130,000 customers were without water at the peak, and that mobile service got worse after the first 24 hours without mains power, when the back-up batteries ran down. The review recommends a programme to help households prepare for the loss of essential services for 72 hours.
What it shows. A big storm can stop the power, the tap water and the mobile network at the same time. The Irish review's planning assumption for a household is 72 hours.
Sources for this event
- Government of Ireland, Department of Housing, Local Government and Heritage (National Directorate for Fire and Emergency Management), Review of Storm Éowyn, Government of Ireland review (opens in a new tab). Page date: 21 October 2025. Read 12 November 2026 in the official PDF.
Hurricane Helene: the Asheville water system
United States, 27 September 2024
The City of Asheville says that its water staff and their partners took 21 days after the storm to restore non-potable water, and 52 days to restore potable water. The United States Environmental Protection Agency says that the city lifted its boil water notice on 18 November 2024. The City of Asheville says that it gave out 3.9 million bottles and cartons of drinking water.
What it shows. After a storm, tap water can take weeks to be fit to drink again, so keep a first supply of drinking water at home.
Sources for this event
- City of Asheville, City of Asheville reflects on 2024 and looks ahead towards 2025, City of Asheville (opens in a new tab). Read 12 November 2026.
- United States Environmental Protection Agency, City of Asheville lifts systemwide boil water notice issued after Hurricane Helene, EPA (opens in a new tab). Page date: 18 November 2024. Read 12 November 2026.
The CrowdStrike software update outage: worldwide
Worldwide, 19 July 2024
CrowdStrike's own preliminary review says that the company released a content update for Windows computers on 19 July 2024 at 04:09 UTC, that the update resulted in a Windows system crash, and that the company reverted the defect at 05:27 UTC on the same day. Microsoft estimates that 8.5 million Windows devices were affected, which is less than one percent of all Windows machines. Microsoft says that the effects were wide because enterprises that run many critical services use the software.
What it shows. An outage can start with a software fault and no storm, so keep paper copies of the details that you would need if screens were down.
Sources for this event
- Microsoft, Helping our customers through the CrowdStrike outage, Microsoft (opens in a new tab). Page date: 20 July 2024. Read 12 November 2026.
- CrowdStrike, Preliminary Post Incident Review (PIR): Content Configuration Update Impacting the Falcon Sensor and the Windows Operating System (BSOD), CrowdStrike (opens in a new tab). Page date: July 2024. Read 12 November 2026.
The Optus network outage: Australia
Australia, 8 November 2023
The Senate committee report says that the outage began at 4.05am on 8 November 2023 and that services were back for 99 per cent of customers at 4.00pm. The Senate committee report says that an estimated 10.2 million Optus subscribers were affected, and that Optus advised that at least 2697 calls did not reach Triple Zero. The Senate committee report says that Optus told the committee that around 50 per cent of payment terminals had no way to move to another provider, so they took no payments during the outage.
What it shows. If your own network fails, an emergency call may not connect, so plan how else you would get help.
Sources for this event
- Parliament of Australia, Senate Environment and Communications References Committee, Optus Network Outage, Chapter 2 - The Optus network outage, Senate committee (opens in a new tab). Read 12 November 2026.
Cyclone Gabrielle: New Zealand
New Zealand, 12 February 2023
The Government Inquiry report says that over 225,000 homes lost electricity in Cyclone Gabrielle, and that some of them were without it for more than ten days. The Government Inquiry report says that power cuts were the main cause of the telecommunications faults, and that many people could not buy food or other necessities, because stores were closed or Eftpos was down. The Inquiry says that emergency provisions for at least one week are more appropriate in urban areas, and for two weeks in more remote or rural areas.
What it shows. The New Zealand Inquiry found that a few days of supplies were not always enough. It says that at least one week is more appropriate for urban areas.
Sources for this event
- Government Inquiry into the Response to the North Island Severe Weather Events (Department of Internal Affairs host), Report of the Government Inquiry into the Response to the North Island Severe Weather Events, Government Inquiry (opens in a new tab). Page date: 23 April 2024. Read 12 November 2026 in the official PDF.
The Rogers network outage: Canada
Canada, 8 July 2022
The federal minister told a House of Commons committee that more than 12 million Rogers clients were directly affected, and that millions of Canadians had no mobile or internet access for more than 15 hours. The minister said that businesses turned customers away because they could not use Interac, and that many people lost the ability to call 911. Interac's own statement says that the outage led to the unavailability of Interac services. The Rogers chief executive told the same committee that the cause was a system failure after an update in the core network.
What it shows. One network fault can stop phones, internet and debit payments on the same day, so keep a little cash and a written list of key numbers.
Sources for this event
- House of Commons of Canada, Standing Committee on Industry and Technology, Evidence, meeting 31, 25 July 2022 (the Rogers Communications service outages), House of Commons committee (opens in a new tab). Page date: 25 July 2022. Read 12 November 2026.
- Interac Corp., Rogers Outage - Interac status update, Interac (opens in a new tab). Page date: 12 July 2022, updated 7 July 2023. Read 12 November 2026.
- Rogers Communications, Opening remarks: Standing Committee on Industry and Technology (INDU) on July 25, 2022, Rogers (opens in a new tab). Page date: 25 July 2022. Read 12 November 2026.
Storm Arwen: United Kingdom
United Kingdom, 26 November 2021
Ofgem, the energy regulator, says that over one million customers lost power and that 82% of customers were reconnected within 24 hours. Ofgem also says that the supply was off for more than three days for around 40,000 customers, and for over a week for nearly 4,000, and a GOV.UK page says that some disruption lasted up to 13 days. Ofgem found that the restoration time given to 28% of customers was wrong by more than 24 hours. The Energy Emergencies Executive Committee review, published on GOV.UK, says that some areas are likely to lose both electricity and telecoms in a major incident.
What it shows. In Storm Arwen most homes had power back within a day, a few waited over a week, and some restoration times were wrong, so treat a restoration time as an estimate.
Sources for this event
- Ofgem (the energy regulator for Great Britain), Final report on the review into the networks' response to Storm Arwen, Ofgem (opens in a new tab). Page date: June 2022. Read 12 November 2026 in the official PDF.
- Department for Business, Energy and Industrial Strategy (GOV.UK), Storm Arwen electricity distribution disruption review, GOV.UK (opens in a new tab). Page date: 2022. Read 12 November 2026.
- Energy Emergencies Executive Committee (E3C), UK government, Energy Emergencies Executive Committee Storm Arwen Review: Final Report, E3C review (opens in a new tab). Page date: 2022. Read 12 November 2026 in the official PDF.
Winter Storm Uri: Texas
United States, 15 February 2021
The FERC and NERC staff report says that more than 4.5 million people in Texas lost power, and that for some of them the power was off for as long as four days. A Texas Comptroller article reports a University of Houston survey: 49 percent of Texans lost running water, and for them the average loss was 52 hours. The Texas Department of State Health Services says that the loss of electricity and of regular heating led many people to use alternate sources of heat.
What it shows. In Winter Storm Uri many homes lost running water as well as power, so store drinking water before winter.
Sources for this event
- Federal Energy Regulatory Commission, North American Electric Reliability Corporation and Regional Entity staff, The February 2021 Cold Weather Outages in Texas and the South Central United States, FERC and NERC (opens in a new tab). Page date: November 2021. Read 12 November 2026 in the official PDF.
- Texas Comptroller of Public Accounts, Winter Storm Uri 2021 (Fiscal Notes), Texas Comptroller (opens in a new tab). Page date: October 2021. Read 12 November 2026.
- Texas Department of State Health Services, February 2021 Winter Storm-Related Deaths - Texas, Texas DSHS (opens in a new tab). Page date: 31 December 2021. Read 12 November 2026 in the official PDF.
Cyclone Fani: Odisha, India
India, 3 May 2019
The Government of Odisha's assessment says that Cyclone Fani reached the coast of Odisha near Puri on 3 May 2019, and that it affected about 16.5 million people. The Government of Odisha's assessment says that the major towns of Puri and Bhubaneswar had their power supply back within two weeks, and that mobile and internet services were disrupted in eleven districts. The same assessment says that in Puri, the worst affected district, electricity restoration took more than a month. The same assessment says that the mobile service of the operator BSNL was disrupted less, because its tower stations had diesel generator sets and stored fuel.
What it shows. In Cyclone Fani mains power took up to two weeks to return in the main towns, and more than a month in the worst affected district, so plan light and phone charging that do not need the mains.
Sources for this event
- Government of Odisha, with the United Nations, the World Bank and the Asian Development Bank (Odisha State Disaster Management Authority host), Cyclone Fani: Damage, Loss and Needs Assessment, Odisha, Government of Odisha (opens in a new tab). Page date: 2019. Read 12 November 2026 in the official PDF.
The Lancaster floods and power cut: United Kingdom
United Kingdom, 5 December 2015
A Royal Academy of Engineering report (the academy is a charity, not a government body) says that electricity supplies to 61,000 properties in Lancaster were cut on Saturday, 5 December, after flooding. The report says that power came back in stages from Monday, was cut again to most areas that evening, and was back to normal by Friday, 11 December. The report says that most mobile phone coverage was lost within an hour, that electronic payment systems and most cash machines (ATMs) did not work, and that homes with gas central heating had no heating. The report also says that FM radio still worked, but many people had no battery radio to hear it.
What it shows. In a wide power cut the mobile phone, the internet and the television can all stop, so a battery or wind-up radio is a simple way to hear local news.
Sources for this event
- Royal Academy of Engineering (a national academy and registered charity, not a government body), Living without electricity: One city's experience of coping with loss of power, Royal Academy of Engineering (opens in a new tab). Page date: May 2016. Read 12 November 2026 in the official PDF.
Put it in your plan
The kit planner works out water, food and the other items for your household, from your own government's advice.
We add an event when an official review or a first-party statement on it is published. This page is not a news service. Spotted an error? Email hello@emergencykitplan.com