Meteorology Chief Mehmet Caglar described the downpour that hit Istanbul as "once in a century."

SHOOT: What happens when they happen twice?

clipped from news.yahoo.com ISTANBUL – Flash floods roared across a major highway and a commercial district in Istanbul on Wednesday, killing at least 20 people and forcing dozens to scramble onto the roofs of cars and trucks. Some of the dead drowned inside their vehicles. Fueled by the worst rain in 80 years, waters rose up to six feet (2 meters) high in the city's Ikitelli district, cutting off the route to Istanbul's main airport and the highway to Greece and Bulgaria on the European side of the sprawling city. The surging water flipped trucks, cars and buses over like matchsticks, crushing them into piles of debris. Trapped motorists desperately climbed out of their vehicles, hoping to be rescued. Helicopters lifted stranded people off rooftops, while inflatable boats fought the swirling waters to go from vehicle to vehicle, picking up survivors. A group of men were seen looting rifles from an overturned cargo truck on a highway, according to private NTV television.