High winds at outdoor events: when to go, hold, stop or evacuate

Operational Tactical Strategic By Kris Dailly, OTAS Insights. Published 20 October 2026. Correct as of 20 October 2026.

Published by OTAS Live Ltd

Storm Austen is the first named storm of the 2026 to 2027 season [2][5]. It brings a Met Office yellow warning for wind across southern England and south Wales from the early hours of Friday 23 October 2026 [1][3]. The Met Office storm naming season runs from early September to late August [5]. This Insight uses Austen as the case, but the core is a wind decision framework you can reuse at any outdoor event with temporary structures. All times are UK time, and every time is labelled British Summer Time (BST) or Greenwich Mean Time (GMT).

In short: do not make wind decisions on the warning colour alone. Get the wind limit for each structure in writing from the people who designed or supplied it. Measure the wind on site. Agree watch, hold, stop and evacuate triggers before the day, and name who makes each call. After the wind, inspect every structure before people go back in.

1. The case: Storm Austen

As published by the Met Office when we checked at 18:26 BST on 20 October 2026:

• Warning: a yellow warning for wind, valid from 00:00 BST to 12:00 BST on Friday 23 October 2026. It was issued at 11:04 BST on Monday 19 October 2026 [3].
• Area: southern parts of England and south Wales [1]. The warning lists local authorities in South West England, London and South East England, Wales and the West Midlands [3].
• Gusts: the Met Office says gusts of 50 to 60mph are likely more widely, and gusts over 70mph are possible on the most exposed coasts [1].
• Likelihood and impact: the Met Office rates the warning as low likelihood (10 to 25%) with significant impact [3].
• Possible impacts: a small chance of injuries and danger to life from flying debris, longer journeys or cancellations and some road and bridge closures. There is also a slight chance of power cuts that could affect mobile phone coverage [3].
• After Friday: further wind and rain are likely through the weekend and into the start of next week [1]. UK clocks go back at 02:00 BST on Sunday 25 October, so later times are in GMT [14].
• Status: the Met Office says warnings are under constant review and could be updated as confidence increases [1]. When we checked, the warnings page also showed a notice that the warnings may be out of date [3]. Always read the live page.

2. What it means for event operations

• A yellow warning is not a green light. The Met Office says a yellow warning can mean significant impacts are possible but less certain [2][15]. Read what the warning says, not just its colour. A storm is named when it could cause disruption or damage that could lead to an amber or red warning [5].
• The forecast is regional. Your site is local. Wind speed normally increases with height and is affected by the ground, buildings and trees [6]. HSE says wind can also funnel through trees, buildings and other structures [9]. It advises finding out the prevailing wind direction when planning where structures go [12].
• Mean wind and gusts are different numbers. The Met Office defines a gust as the highest 3-second average in a period. Mean wind is the average over the 10 minutes before the reading [6]. In its forecast tables, the speed is the mean and the gust is the highest speed expected before the next time shown [7]. Know which one each of your limits refers to.
• Units need to match. The Met Office measures wind in knots and gives 1 knot as 1.15 miles per hour (mph) or about 0.51 metres per second (m/s) [6]. Convert every limit into the unit of the forecast you are using, before the event.
• Damage builds up. The Met Office says structures weakened by an earlier storm can be damaged by gusts that are not particularly strong. It also says later windy spells can hamper recovery [4].

3. A wind decision framework

The framework below is OTAS Insights guidance built on the official sources cited. It does not set any wind speed. Every number in it comes from the people responsible for each structure.

Limits: get them from the people who designed the kit

Your thresholds come from the designer, supplier or manufacturer of each structure, not from a forecast or a rule of thumb. HSE refers to the design operating wind speeds of outdoor equipment [8]. For sealed inflatables, HSE says the manufacturer's maximum safe wind speed should be stated on the device and in the operations manual [9]. For each structure, ask in writing:

• the wind limit, whether it is a mean wind or a gust, its unit and the height it applies to
• what to do at each stage, for example removing banners, lowering or stopping use
• how long each action takes and how many trained people it needs

Research commissioned by HSE found that adding banners to structures can be a significant issue if the design did not allow for the extra wind loading [10]. HSE also says equipment made only for indoor use should not be used outdoors [8].

Monitoring: measure where the risk is

• Measure on site. HSE's guidance for inflatables says to use a suitable anemometer, placed clear of the structure, with readings taken in the direction of the wind. It says smartphone weather apps are not a substitute [9].
• Watch the warnings. Check the Met Office warnings and forecast at agreed times, and sign up for alerts [15].
• Write it down. Name who takes readings, how often, where and who they report to. Log every reading with the time.

Trigger points: agree them before the day

Agree four stages with each supplier, and write the readings that trigger each one:

• Watch: a warning or forecast gusts near your limits. Increase readings, brief crews, check ballast and fixings.
• Hold: readings approach an agreed level below the limit. Pause lifts, work at height and new builds. Hold people back from affected areas.
• Stop: the supplier's action level is reached. Stop use of the structure, carry out the supplier's actions and keep people clear.
• Evacuate: the limit is reached or a structure shows signs of distress. Clear the fall zone, or the site, using your emergency plan.

HSE's guidance for inflatables says to take them out of service before the limiting wind speed is reached [9]. Where there are no adverse weather arrangements for a tower, HSE says an exclusion zone of about 1.5 times the tower height may be prudent [8].

Decisions: who can say go, hold, stop or evacuate

Decide in advance who can make each call alone, and who needs to be told. The options are go, modify, hold, stop, evacuate, postpone or cancel. Decide early enough to carry out each action safely. HSE says build up and breakdown are likely to be when the highest-risk work happens [11]. Record each decision with the time, the readings and the reason.

Communications: plan for the worst signal

HSE lists weather forecast news among the information to give people at site inductions and briefings [11]. Agree short, ready-written messages for crew, contractors, audiences and partners. The Austen warning mentions possible power cuts affecting mobile phone coverage [3], so have a fallback such as radios. Plan ingress and egress around the warning times, because the Met Office warns of travel disruption [3].

Recovery: inspect before you reopen

• Research for HSE says structures need regular inspection by a competent person [10]. After high winds, check ballast, guys, anchors and the ground before use resumes. HSE says ballast should stay in place for as long as a structure is in use [8].
• Recheck before each further windy spell [4].
• Debrief and update the risk assessment. In England, Wales and Scotland, employers must review a risk assessment if it may no longer be valid or there has been a significant change [13].

4. Where the law applies

In England, Wales and Scotland, employers must make a suitable and sufficient assessment of the risks to their employees and to others affected by their work [13]. HSE guidance covers Great Britain. In Northern Ireland, health and safety at work is enforced by the Health and Safety Executive for Northern Ireland (HSENI) [16]. Met Office warnings cover the whole UK [15].

Checklist

• Before the event: wind limits in writing for every structure, with mean or gust, unit and height. Actions, timings and crew numbers agreed. Trigger readings for watch, hold, stop and evacuate agreed. Decision makers and deputies named
• On the day: Met Office warnings checked at agreed times. Anemometer in place and readings logged. Crew briefed on the forecast and the triggers. Messages ready. Radio fallback tested
• After the wind: competent inspection before reopening. Decisions and readings recorded. Debrief held. Risk assessment reviewed

Action box

Frequently asked questions

Does a yellow wind warning mean an outdoor event can go ahead?

Not on its own. The Met Office says a yellow warning can cover weather likely to cause some disruption, or much more significant impacts that are less certain [2][15]. Read the impacts and likelihood in the warning, then check the forecast against the limits for each of your structures.

What wind speed should an outdoor event stop at?

There is no single figure that suits every event. The limits come from the designer, supplier or manufacturer of each structure [8][9]. Ask for them in writing, with the unit, the height and whether they refer to a mean wind or a gust.

Should I use the mean wind speed or the gust?

Use whichever your supplier's limit refers to, and check both. The Met Office defines a gust as the highest 3-second average in a period, and mean wind as the average over 10 minutes [6]. Its forecast tables show both [7].

Can I use a weather app to monitor wind on site?

Not as your only measure. HSE's guidance for inflatables says smartphone weather applications are not a substitute for an anemometer, because they do not take local wind conditions into account [9]. Use a suitable anemometer on site and keep checking the Met Office warnings.

When should we decide to postpone or cancel?

Early enough to carry out every action safely. Lowering, emptying or taking down structures takes time and trained crew. HSE says build up and breakdown are likely to be when the highest-risk work happens [11].

What should happen before a site reopens after high winds?

Research for HSE says structures need regular inspection by a competent person [10]. After high winds, check ballast, guys, anchors and the ground before use resumes. Recheck before each further windy spell, because the Met Office says earlier storms can weaken structures [4].

Related OTAS Insights

These are links to other OTAS Insights pieces, not to any OTAS Live product or service.

• The new duty to prevent harassment of crew by the public, for briefing and supporting crew on site. https://otas.live/insights/employer-harassment-duty/
• Working in the Middle East, a travel safety briefing for event professionals, for planning crew travel and check-ins. https://otas.live/insights/middle-east-travel-safety/

This Insight is general information, not legal, engineering or weather advice. It does not replace your risk assessment, supplier instructions or current Met Office warnings. Check the live sources below before acting.

Interest: OTAS Live Ltd, which publishes EPGN, sells event operations services, handbooks and training related to this topic.

References

All web sources accessed 20 October 2026, between 18:26 and 18:31 BST. Sources 1 to 7 and 15 are Met Office pages. Sources 8 to 14 and 16 are not Met Office pages and are labelled with their publisher.

1. Met Office, 'Storm Austen named', news release, 10:45 BST, 20 October 2026. https://www.metoffice.gov.uk/about-us/news-and-media/media-centre/weather-and-climate-news/2026/storm-austen-named
2. Met Office, 'What does it take for a storm to be named?', Met Office blog, 20 October 2026. https://www.metoffice.gov.uk/blog/2026/what-does-it-take-for-a-storm-to-be-named
3. Met Office, 'UK weather warnings', yellow warning for wind issued 11:04 BST, 19 October 2026, viewed 18:26 BST, 20 October 2026. https://weather.metoffice.gov.uk/warnings-and-advice/uk-warnings
4. Met Office, 'What are the National Severe Weather Warning Service Impact tables?'. https://weather.metoffice.gov.uk/guides/severe-weather-advice
5. Met Office, 'UK Storm Centre'. https://www.metoffice.gov.uk/weather/warnings-and-advice/uk-storm-centre/index
6. Met Office, 'How we measure wind'. https://weather.metoffice.gov.uk/guides/observations/how-we-measure-wind
7. Met Office, 'What does this forecast mean?'. https://weather.metoffice.gov.uk/guides/what-does-this-forecast-mean
8. Not Met Office: HSE, 'Outdoor equipment to support speaker clusters, lights etc'. https://www.hse.gov.uk/event-safety/outdoor-equipment.htm
9. Not Met Office: HSE, 'Sealed inflatables: safe supply, inspection and operation. 6. The operator's responsibilities'. https://www.hse.gov.uk/entertainment/fairgrounds/inflatables/operators-responsibilities.htm
10. Not Met Office: Health and Safety Laboratory for HSE, 'Identification of safety good practice in the construction and deconstruction of temporary demountable structures', 7 December 2011. https://www.hse.gov.uk/event-safety/assets/docs/demountable-structures.pdf
11. Not Met Office: HSE, 'Managing an event'. https://www.hse.gov.uk/event-safety/managing-an-event.htm
12. Not Met Office: HSE, 'Venue and site design'. https://www.hse.gov.uk/event-safety/venue-site-design.htm
13. Not Met Office: 'The Management of Health and Safety at Work Regulations 1999', regulation 3 (risk assessment). https://www.legislation.gov.uk/uksi/1999/3242/regulation/3
14. Not Met Office: GOV.UK, 'When do the clocks change?'. https://www.gov.uk/when-do-the-clocks-change
15. Met Office, 'Weather warnings guide'. https://www.metoffice.gov.uk/weather/guides/warnings
16. Not Met Office: Health and Safety Executive for Northern Ireland (HSENI), home page. https://www.hseni.gov.uk/

OTAS Live Ltd. Registered in Scotland, company number SC755102.

Share this article on X (opens x.com) or follow @otaslive

Corrections to published Insights articles are listed in our corrections log.