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The eruption of a volcano under the Eyjafjallajokull glacier of Iceland on Wednesday, April 14, sent ripple effects around the globe as it halted international flights to and from Northern Europe. Airborne volcanic ash posed a threat to jet engines, and to prevent disaster, air traffic controllers grounded planes.
From the earliest moments of the eruption, a global network of Volcanic Ash Advisory Centers began monitoring the ash plume and the appropriate centers issued advisories about flow of the ash through the atmosphere. There are nine such centers, each responsible for a defined geographic region.
NOAA operates two Volcanic Ash Advisory Centers that are poised to take action should a volcano spew ash into the atmosphere. One covers Alaska, and the other the rest of the United States, including U.S. Pacific territories, as well as the Caribbean, Mexico, Central America, and the northern part of South America.
NOAA’s U.S. Volcanic Ash Advisory Centers issued nearly 2,000 Advisories over the last year and a half. “That means volcanic ash is frequently in the air,” says Barbara Stunder, a NOAA Research meteorologist with the Air Resources Laboratory in Silver Spring, Md. “We have to be prepared.”
Although most eruptions effect limited local areas, the potential for one to suspend air traffic is always present. The Smithsonian’s Global Volcanism Program maintains a database of 1,585 named volcanoes around the world. In the United States, Mount St. Helens in Washington, Redoubt in Alaska, and Anatahan in the Northern Mariana Islands in the Pacific, have all threatened lives and property.
The Air Resources Laboratory developed a computer model for tracking where smoke, chemicals and other particulates — such as volcanic ash — travel and disperse with the winds. The model, known as HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) is one key component of NOAA’s volcano preparedness.
Another key ingredient is satellite imagery. NOAA’s National Environmental Satellite, Data, and Information Service provides snapshots of volcanic ash plumes from space. These images show the actual progress of ash over time.
When alerted to a large volcanic eruption threatening the U.S. Volcanic Ash Advisory Centers’ geographic areas of responsibility, experts with NOAA’s National Weather Service run the HYSPLIT model. Armed with satellite images and model data, the appropriate Volcanic Ash Advisory Center will issue advisories which describe the current ash location and project where the ash plume will be in 6, 12, and 18 hours.
NOAA’s role is part of a larger National Volcanic Ash Operations Plan for Aviation for the United States. The Federal Aviation Administration, the U.S. Air Force, the Smithsonian Institution, the U.S. Geological Survey, and NASA are also partners in protecting U.S. lives and property.