Why a unique US lightening law could stop the F1 Miami Grand Prix

This weekend’s Formula 1 Miami Grand Prix could be disrupted by thunderstorms.

Weather forecasts suggest rain will affect proceedings in Miami, with an 88 percent chance of rain on Sunday and a 53 percent chance of thunderstorms, according to AccuWeather, which is used by several F1 teams.

While heavy rain itself could cause complications and delays, the bigger concern surrounds the thunderstorm forecast.

That is because the United States has specific laws that require major outdoor public events to be halted if there is a risk of lightning strikes in the area.

These are backed by OSHA (Occupational Safety and Health Administration) obligations for on-site workers, which require organisers to suspend events whenever there is an imminent lightening risk.

Florida records more lightning strikes per square mile than any other US state.

Spectators and guests would be directed to shelter and the medical helicopter would not be able to fly due to conditions being considered too dangerous.

Due to the local public safety requirements, F1 would be powerless to overrule such obligations were they to be required.

Conditions are forecast to be at their worst during Sunday afternoon - right when the Miami Grand Prix is due to start.

If the race had already started, it could be stopped with a red flag. Under red flag conditions, drivers are required to return to the pit lane.

In such a scenario, teams would be permitted to bring their cars into the garages and work on them during a red flag, rather than doing so outdoors in the pit lane, as is normally the case.

Friday and Saturday are set to be unaffected by rain and thunderstorms, with practice, sprint qualifying, the sprint race and regular grand prix qualifying all currently forecast to be dry.

F1’s governing body the FIA says the situation is being closely monitored and a contingency plan has been put in place.

"We are closely monitoring the weather forecast for this weekend,” an FIA spokesperson told Crash.net.

“Having faced a similar situation last year in Miami with threats of thunderstorms, we have a contingency plan in place and will activate it if needed to minimise disruption to the on-track programme."