Deaths have been reduced because of early warning systems and other factors but the economic toll on a community's housing, health and infrastructure still is devastating, said UN deputy humanitarian coordinator Margareta Wahlstrom.

“The great risk is that large numbers of people are living in the most vulnerable areas in the world,” Mr Wahlstrom told a news conference, noting serious flooding was not restricted to South Asia, the heaviest hit, but had struck all continents.

He said that between 2004 and 2006, the number of natural disasters had increased from an average of 200 to 400 a year, including heat waves, droughts, wildfires and storms.

Floods increased from 60 to 100 per year in that time span and in 2007 some 70 serious floods have been registered, including in Sudan, Ethiopia, Myanmar, Philippines, Vietnam, Indonesia, China, India, Bangladesh, Nepal, Pakistan, Afghanistan and Colombia.

Changes in weather patterns were documented on August 8 by the Geneva-based World Meteorological Organization (WMO), which noted natural disasters hit the poor hardest.

Heat waves were above average in Africa, Asia, Europe and South America. And the Arabian sea near Oman had it first ever documented cyclone, WMO said.