Lightning safety for workplaces, schools and outdoor events

01

Why does an event need a written policy?[1]

Because the decision to stop is made under pressure. A referee, site manager or teacher deciding in the moment faces a crowd that wants to continue, and a written trigger removes the judgement call from someone who is being argued with.

The failure mode is predictable: everyone can see the sky, nobody wants to be the one who cancels, and the decision slides until rain forces it. That delay covers exactly the window when strikes arrive ahead of the rain.

Naming a single person with authority solves half the problem. Naming an objective trigger solves the other half, because it converts a debate about risk into an observation anyone can make.

02

What should the trigger be?[1]

Thunder heard is the baseline, since it means you are already within striking distance. Larger venues that need lead time to move crowds commonly add a detection-based trigger, such as any strike inside a set radius, typically 8 to 16 kilometers.

Evacuation time is the reason big venues cannot rely on thunder alone. Clearing a stadium takes far longer than clearing a school field, so the trigger has to fire while the storm is still distant enough to allow the movement to finish.

Work backwards from how long your site takes to clear. If moving everyone to shelter takes 20 minutes, a trigger that gives you 10 is not a policy, it is a hope.

03

What counts as shelter for a crowd?[1][2]

Substantial buildings with wiring and plumbing, or hard-topped vehicles. Tents, marquees, grandstands, dugouts and open-sided structures do not qualify. Capacity has to be identified in advance, because a plan that shelters a third of the crowd is not a plan.

Named buildings

Specific structures with capacity figures, not 'the nearest building'

Vehicles

Cars and buses with metal roofs and closed windows count

Marquees and tents

No protection. Often the worst place, being tall and metal-framed

Grandstands

Open structures. Usually shelter from rain only

Restart authority

One named person, one 30-minute clock, no exceptions for schedules

04

What do outdoor workers need?[1]

The same triggers, plus a way to receive warnings in the field and a realistic path to shelter. Construction, roofing, landscaping, agriculture and utility work all put people in exposed positions with equipment they cannot abandon instantly.

Elevated work is the sharpest case. Getting off a roof, a scaffold or a lift takes time, and it has to start before the storm is overhead rather than when the first thunder sounds.

Vehicles usually solve the shelter problem on work sites, since most crews have a van or truck nearby. That is a genuine advantage over sports venues, where the parking is often far from the field.