Storm and flood readiness (UK)

Storms and floods are the most likely reason a UK household loses power and communications for more than a few hours. This guide uses the official Storm Arwen reports to show what failed, summarises what government now asks of households, and is honest about the small part a LoRa mesh can play.

Storm Arwen in numbers

Storm Arwen hit on 26 and 27 November 2021. The Energy Emergencies Executive Committee (E3C) review for BEIS, whose final report was published on 9 June 2022, found electricity disruption to just over 1 million customers, with 83% restored within 24 hours. "A small but significant proportion" experienced disruption of up to 13 days. State both: most people were back within a day, and a minority waited much longer. The figures cover England, Scotland and Wales; Northern Ireland is separate.

On communications, the E3C final report said:

• rural and coastal communities "suffered disproportionately", with less overlap of mobile phone coverage from multiple cell sites;
• a minority of areas lose both electricity and telecoms, making it "harder or impossible to learn about available welfare";
• for people without telecoms it recommended considering local radio, leafletting and local resilience partners;
• where hardening networks is uneconomic, "it is necessary to ensure that enhanced contingency plans are in place instead";
• network operators' field staff were also affected: SSEN said teams "spent time attempting to locate a mobile signal".

The Electronic Communications Resilience and Response Group (EC-RRG) report of May 2022 reported three fatalities across the UK from the storms, almost 1 million properties without power, and thousands of mobile cell sites disrupted across all four mobile operators. Mobile battery resilience "was depleted after a number of hours". The core network ran on generators with fuel for up to 5 days, and tow-to-site generators and temporary cell sites were used. It also said the Met Office warnings "did not provide significant advance notice".

Other UK cases

• Storm Eunice, February 2022. The E3C report also took Eunice into account, and found inland and urban areas had more overlapping mobile cells and so fewer mobile impacts.
• Storm Eowyn, 24 January 2025. Trade press (ISPreview, citing Ookla analysis) reported large drops in mobile speeds in Scotland and Northern Ireland. We found no Ofcom or government review, and we have not confirmed the figures, so we give none.
• Winter 2025/26 storms and summer 2026 wildfires. The government's 22 October 2026 press release refers to these as having disrupted phone signal, water and internet. We read no incident-level detail.

What government asks households to do

The Be Ready campaign (first stage of a three-year campaign, announced 22 October 2026) advises being ready for three days of disruption, signing up to the Priority Services Register, and keeping non-perishable food and bottled water. It also invites people to volunteer and support their community. Scotland and Northern Ireland have their own sites, linked from the Be Ready page. We did not read the full checklist, so do not take this page as a list of what it recommends.

Other starting points:

• gov.uk publishes contact details for local resilience forums (page updated 11 February 2026 per gov.uk's index; we did not read the page body).
• For floods, read gov.uk's pages "What to do before or during a flood" and "Flood alerts and warnings: what they are and what to do". We have not summarised them here and we do not print a Floodline number, because we have not confirmed it.
• The Cabinet Office's telecoms resilience guidance (last updated 5 December 2019) lists five principles, including "Ensure diversity of your technical solutions" and "Adopt layered fall-back arrangements", and warns that "there is no silver bullet". Layering is the right way to think about a mesh: one extra layer, not the only one.

A community plan

The Arwen reports describe people with neither power nor telecoms and no way of reporting a fault or learning what help was available. A mesh does not fix the power, but it can cover part of the communication gap for a group that prepared in advance.

1. List who is vulnerable. E3C noted the Priority Services Register did not capture people who only became vulnerable because of how long they went without services, so know your neighbours.
2. Choose a hub. A village hall, church or a household with a generator or a reliable battery. Agree it in advance.
3. Keep a paper list of names, addresses and phone numbers. E3C points to leaflets and local radio because they work when phones do not.
4. Agree a check-in schedule for the hub and the street.
5. Know the fault routes. 105 reports a power cut (England, Scotland, Wales); see the power-cut plan. 999 or 112 are for emergencies.
6. Charge up power banks and phones when a warning is issued. See Power.

Where a mesh fits, and where it does not

It can help:

• neighbour-to-neighbour check-ins when masts are down and the street is dark;
• a pre-agreed group of equipped households, or a hub coordinating them.

It cannot:

• reach 999 or the network operator on 105, or give you internet access (some nodes can relay messages to the internet through an MQTT gateway if one has a working connection);
• bring back power;
• work without people who already have nodes within a few radio hops. See find a local mesh or start with no hardware;
• be promised to integrate with any emergency service. The response in the Arwen reports relied on utilities, local resilience partners, local radio and leafletting.

Floods are a hazard for the nodes themselves. These points are general advice, not sourced from a report: mount a node above likely water, use a sealed enclosure, and expect a ground-level node to be lost. We give no range or waterproofing figures because we have no sourced ones. Radio rules for UK use are on UK radio rules at a glance; the UK uses 868 MHz (EU_868) at up to 500 mW e.r.p. in 869.40 to 869.65 MHz with a 10% duty cycle under Ofcom IR 2030 v1.16 (published 7 April 2026). Do not use 915 MHz settings.

Do not copy US cases such as Hurricane Helene as UK evidence. Resilience in practice keeps them separate and says what was verified. What you can actually do sets out expectations.

FAQ

How long did power cuts last after Storm Arwen?

The E3C review found 83% of just over 1 million disrupted customers were restored within 24 hours, while a small but significant proportion were disrupted for up to 13 days.

Will my mobile work if the power is out?

Not necessarily. After Storm Arwen the EC-RRG said mobile site batteries were depleted after a number of hours. Ofcom says a 999 call will connect through another network if one is available.

What should I do to prepare for a storm or flood?

Government advice is to be ready for three days of disruption, join the Priority Services Register and keep food and water. For floods, read gov.uk's flood pages and know your local flood warnings.

Can a LoRa mesh work when the mobile network is down?

It can pass short text between people with nodes within radio reach, without masts or the internet. It cannot call 999 or anyone outside the mesh.