The hidden, human cost of heat waves

ATLANTA, Georgia (CNN) -- Every year, natural disasters wreak havoc in the United States, producing dramatic scenes and billions of dollars in damages. But while major storms and earthquakes may garner more headlines and incur heavier financial losses, a less obvious weather phenomenon -- heat waves -- produce among the highest human costs of all such disasters.

Statistics gathered by the World Health Organization show that heat waves account for the two top deadliest weather-related disasters in the United States over the last decade -- and three of the top five.

While the financial damage from a heat wave may not be as high or as evident as that caused by a hurricane or earthquake, high temperatures do come at a cost. For instance, the WHO said government agencies spent $3.7 billion on a heat wave that struck pockets of the country in summer 1998.