The risks associated with the wind are not common knowledge among the general public, and this is precisely why event planners must monitor the weather in outdoor events with crowds. Perception of wind risks is also subjective: we know by instinct that we should stay away from fire or falling objects, but evaluating wind hazards based on perception alone is not possible. The danger is obvious when storm-force winds are tearing away roof shingles and tree branches, but many accidents are caused by gusts that occur on days with mild or moderate weather.
In outdoor events, temporary structures such as tents and stages are especially vulnerable to strong winds. These structures lack the strength of a permanent building, and violent gusts or turbulent winds can cause their collapse. Note that there are two main ways in which collapse can occur:
- A very strong wind can exceed the loading capacity of a structure, causing its collapse.
- However, cyclical forces such as those caused by turbulence can also cause structural collapse due to fatigue failure, as explained in our previous article on turbulence.
A common misconception is that you can manage outdoor events based on weather forecasts or handheld sensors. However, both approaches come with severe limitations:
- Weather forecasts provide no information on gusts, and their data is for broad areas. For the simple reason that weather stations cannot measure the wind everywhere, a forecast does not reflect site-specific information, or the influence of obstacles like terrain features and constructions.
- Handheld sensors only allow ground-level measurements and require permanent attention by one of your staff members. In addition, getting reliable data is not possible close to the ground, since even short obstacles disrupt the wind.
Keep in mind that the wind can also cause less severe accidents – tent and stage collapses are a worst-case scenario. For example, wind gusts can fling objects at high speed, and there are normally many objects on the ground and in tables at outdoor events. We do not consider some of these objects dangerous until they are flying around at high speed: plastic cutlery and frying pans with hot cooking oil are two clear examples. Also consider that walking becomes more difficult when the wind is strong enough.
If there is an accident in an outdoor event, the last thing you would want is a scared crowd that is difficult to evacuate due to harsh weather. Ideally, you should measure the first warning signs of dangerous winds and take quick action.
Mitigating Wind Risks With Weather Monitoring
Countries normally have stringent building codes that are legally enforced, but lack of standardisation is evident when dealing with temporary structures and venues. This adds to wind-related risks, since you have many persons who are unaware of hazards close to structures of limited strength.
When it comes to wind safety in outdoor events, planning is extremely important – temporary structures should be properly designed, according to the wind conditions expected. Once the event has started, a top priority is to have a reliable monitoring system at the venue.
Three key requirements for wind monitoring are accurate measurement, connectivity to retrieve live data, and being able to notify hazards automatically in case the event staff are busy when dangerous wind conditions are imminent. The wind profile can change very quickly, but cancelling the event should be considered the last safety measure; however, with reliable monitoring, you can deploy preventive measures well in advance.
- Accurate measurement is important to avoid a false alarm. An outdoor event can be ruined by an unnecessary evacuation.
- Connectivity is vital for the event staff to check weather conditions as needed. A wind monitoring devices that can only hold information locally is useless if mounted on a tower nobody can access. A smartphone application provides the most effective way to share information – everyone with a smartphone is familiarised with apps, and their learning curve is very quick.
- Automatic alarms and notifications ensure a response to risks, by making staff members aware of them. The weather is very likely at the bottom of the priority list when an event is ongoing, so the monitoring system must be capable of drawing attention.
Weather monitoring also provides a data file that can be analysed if an incident occurs or the event is cancelled, to improve planning and decision-making in future events. Weather data is also useful as evidence if there are legal procedures after an accident or event cancellation, ensuring that liabilities are held by the party who is truly responsible. This is a drastic example, but it makes the point that weather data is useful even in the worst-case scenario.
WINDCRANE is a rugged and adaptable solution, with an enclosure that is impact-resistant and water-tight. This way, you can retrieve data even if the unit was mounted on a collapsing structure. In addition, WINDCRANE comes with GSM connectivity and automatic alarms, making sure all key staff members are informed about the weather at events.