YOU wouldn鈥檛 want these raindrops falling on your head. Measuring up to 8.8 millimetres across, making them the largest ever recorded, they were discovered in clouds over a burning rainforest in Brazil and over the Marshall Islands in the Pacific.
Typically, raindrops never grow to more than 5 millimetres across. Beyond that size they break into smaller droplets when they crash into each other, or disintegrate during free-fall.
Peter Hobbs and Arthur Rangno at the University of Washington in Seattle discovered the record-breaking raindrops when they were trawling through atmospheric data collected by their research aircraft between 1995 and 1999 (Geophysical Research Letters, vol 31, p L13102). Some may even have been as much as a centimetre across.
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These giant drops must somehow have evaded multiple collisions inside the cloud. 鈥淧ossibly they followed a fortuitous path through the cloud and grew by gathering other droplets,鈥� Hobbs says. He also speculates that they may have had a head start, by forming around ash particles over the blazing forest in Brazil and around particles of sea salt in the air over the Marshall Islands. The massive raindrops must have been quite numerous, since they were found in sample volumes of less than one litre.