from the volcano. Eruption columns are not usually visible on weather radar and may be obscured by ordinary clouds or night. Because of the risks posed to aviation by eruption columns, there is a network of nine Volcanic Ash Advisory Centers around the world which continuously monitor for eruption columns using data from satellites, ground reports, pilot reports and meteorological models. See also Cryovolcano Enceladus – a volcanically active moon of planet Saturn Mount Pelée Pele (volcano) Peléan eruption Plinian eruption References Further reading External links USGS information Description of Galunggung eruption column Volcanoes Volcanic eruptions Explosive eruptions Volcanic degassing Tephra