"Extreme rainfall" refers to a very heavy and intense amount of rain that falls in a short period of time. It means there is a lot of rain coming down at once, causing potentially severe flooding and other related problems. Full definition
A warmer atmosphere can hold more moisture, for example, which raises the risk of extreme rainfall events and the flooding they cause. (realclimate.org)
The scientists found greenhouse gases in the atmosphere as a result of human activity have increased the risk of extreme rainfall in the southern part of the country by about 25 per cent. (carbonbrief.org)
Scientists show that devastating increases in extreme rainfall over the last 30 years fit in with global temperature rise caused by greenhouse gases. (climatenewsnetwork.net)