The NOAA Coral Reef Watch program uses satellite data to provide current reef environmental conditions to quickly identify areas at risk for coral bleaching. Bleaching is the process by which corals lose the symbiotic algae that give them their distinctive colors. If a coral is severely bleached, disease and death become likely. Coral Reef Watch also offers a modeled Outlook that predicts the likelihood of coral bleaching heat stress on a week-by-week basis, up to four months in the future (the typical length of a bleaching season).
Secretariat of the Pacific Regional Environment Programme
A direct internet link to the NOAA Coral Reef Watch website