Dubai floods: Exact cause of 'once in a generation' rainfall - links to cloud seeding fact-checked

Experts have had their say over claims that cloud seeding caused the ‘once in a generation’ rainfall in Dubai.

Heavy thunderstorms lashed the United Arab Emirates on Tuesday, submerging major highways and unleashing chaos at Dubai’s international airport. At least one person died in flash flooding. State-run media described the downpours as a “historic weather event” that surpassed “anything documented since the start of data collection in 1949”.

The flooding sparked speculation that cloud seeding, which involves flying small planes through clouds and spreading chemicals which triggers rainfall, may have contributed to the storms. The UAE is known to operate a cloud seeding programme – but experts have said this is not to blame for the downpours.

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Some people have said cloud seeding may have caused the downpours – but experts said this is not likely

Instead, it is attributed to the emergence of a mesoscale convective system (MCS), which occurs when storms become interconnected around a weather front. Professor Suzanne Gray, Professor of Meteorology at the University of Reading, said: “Satellite imagery suggests the flooding and rainstorms Dubai were caused by something called a mesoscale convective system. Mesoscale convective systems are what we get when lots of individual thunderstorms amalgamate to form a single large high-level cloud shield, typically hundreds of kilometres across, together with a large region of heavy rainfall.

“They are not rare events for the Middle East. A recent published study analysed 95 events that occurred over the southern Arabian Peninsula from 2000-2020 and found that they most often occur in March and April. A previous event in March 2016 caused more than 240mm of rain in Dubai in just a few hours, similar to the totals being reported for this event. This study also found that these MCSs have increased in longevity over the UAE over this 21-year period. MCSs do occur in the UK, but typically just a couple of times a year during the warmer months when they are usually associated with a plume of warm air coming from Spain.”

The rainfall was the heaviest to hit the UAE since records began in 1949

The storms caused major disruption at Dubai’s international airport

Another scientist said we should be talking about global warming, and not cloud seeding, in the aftermath of the dramatic storms. Prof John Marsham, Met Office Joint Chair at the University of Leeds, said people globally “must prepare for unprecedented extremes” as climate change continues to develop – and warned that this will worsen until we reach net zero.

He said: “We know that man-made climate increases extreme rainfall – this is well understood physics as warm air holds more water. A rainfall event such as the one that caused the Dubai floods, which covered a large area and where over Dubai a year’s worth of rain fell in one day, cannot happen without large-scale weather conditions driving enormous convergence of water vapour in the atmosphere and so extreme rainfall. Any possible effect of any cloud seeding in these circumstances would be tiny. This is consistent with the fact that weather models gave a warning of the risk of severe flooding days ahead.”