Credit: KHIN MAUNG WIN/AFP/Getty Images

As the death toll from Cyclone Nargis climbs to an estimated 100,000 or even higher in Myanmar, researchers are working to identify the factors that made it so deadly.

The category-4 Nargis, which struck Myanmar on 2 May, has far surpassed the death toll of Cyclone Sidr, which killed at least 3,500 people in Bangladesh last November, and is approaching that of the 1991 Bangladesh cyclone, which killed some 138,000.

Mangroves and coastal forests in Myanmar's Irrawaddy Delta have been extensively cleared in the past decade, mainly to make way for shrimp farms and rice paddies. The loss of that natural protective barrier intensified the destruction, conservation experts say. Areas where mangroves had been conserved saw less destruction than other regions in the 2004 Indian Ocean tsunami.