Flash floods can spell enormous death tolls and unprecedented destruction to towns and infrastructure. But in some parts of the world they're annually welcomed.
There are two basic types of floods: river floods, when water climbs above the edges of a river and cover a floodplain with water, and flash floods, when a large quantity of water rapidly sweeps over an area.
Flash floods are caused by heavy intense rainfall, over saturated or frozen soil, high river, reservoir and stream levels, ice jams in rivers and urbanisation.
In the UK five million people are vulnerable to flooding each year. Cornwall’s Bocastle flood of 2004 was among the most extreme in British history. Incredibly, there were no human casualties but extensive damage was caused throughout the village.
In 1864, Sheffield saw one of the worst man-made disasters in British history. A crack appeared in the new Dale Dyke Dam and a large section of the dam collapsed unleashing 650 million gallons of water onto the unsuspecting population below. 250 people died and the scene was said to resemble an eight mile long battlefield.
Named after the highest hill on Bodmin Moor, the "Brown Willy Effect" is a meteorological phenomenon defined as heavy rainfall developing over high ground which then travels long distances downwind. On 27 March 2006, a continuous line of showers stretched from Brown Willy to Oxfordshire - a distance of 145 miles.
Just six inches of fast moving floodwater is enough to knock you off your feet and two feet of water will easily sweep a car away. Flash flooding in India resulted in scores of elephants being swept away from the Nameri game reserve.
In 2005 the US National Weather Service reported more people die each year in floods, than by lightning, tornados or hurricanes. More than half of these fatalities occur inside vehicles.
Even the driest regions on earth can experience flooding. In 2003 the Sahara desert experienced its heaviest rains in several years, causing wadis (temporal rivers) and temporal lakes to be created.
A flash flood in New Zealand swept a goldfish out of its pond and carried it for a mile before it was rescued from a roadside ditch and returned to its owners. They renamed it Nemo.
95% of those who were killed by the 1976 Big Thompson Canyon flood in Colorado, died trying to outrun the water along its path rather than climbing to higher ground.
One third of flooded roads and bridges are so damaged by water that any vehicle trying to cross stands only a 50% chance of making it to the other side.
A 2002 severe flood in Mozambique caused extensive damage to homes and crops. Villages in Caia witnessed a skinny dog emerging from the bush, with a tiny monkey clinging to its back - the pair, named Billy and Kiko by the villagers, have been inseparable ever since.
On arriving in Venice in the late 1930s on assignment for the New Yorker magazine, American writer and humourist Robert Benchley telegrammed his editor the words: "Streets flooded. Please advise."