English: The MISR data indicate that, on May 6, the top of the plume was injected to roughly 1.5 kilometers (1 mile) above sea level, but then descended several hundred meters as it moved 140 kilometers (90 miles) downwind. Winds blew the plume southwest along the coast, but over the ocean, away from people. Low plumes like this are closely watched because they can pose health hazards if harmful gases and particles move toward population centers. If plumes are particularly long-lived or intense, they can also cause damage to ecosystems.