Disaster alert! Complex weather events big drain on global economy

First came a dry spell that parched the land, then a spark, followed by some wind. Suddenly, swaths of South Carolina were consumed by voracious flames. More than 100 fires ignited in the state last weekend - an unusually high total even in the heart of fire season. It was the perfect combination of arid air, dry fuels and gusting winds that combined to spread the flames, said Doug Wood, a spokesman for the state's Forestry Commission.

The South Carolina disaster is the latest high-profile example of compound weather, or two or more concurrent events that collectively yield a result worse than if each had occurred on its own. It's a global phenomenon - and its prevalence portends the risks ahead. Malaysia recently struggled with floods that killed at least five people, sent thousands fleeing their homes, crimped palm oil production and caused mudslides. In January, a cascading series of weather disasters led to Los Angeles wildfires that killed 29.

As the planet heats up and weather whiplash spreads, compound weather events are poised to wreak greater havoc: A study published last year projected climate damages could cost the global economy $38 trillion (in 2005 dollars) per year by mid-century.