- Volcanic ash clouds are a serious hazard to aviation, reducing visibility, damaging flight controls and ultimately causing jet engines to fail.
- Heffter, J.L., B.J.B. Stunder, and G.D. Rolph, 1990: Long-range forecast trajectories of volcanic ash from Redoubt volcano eruptions.
- Volcanic ash is a significant hazard to aviation, causing engine failure, damage to avionics systems and abrasion to exposed airframe parts.
- Inhalation of volcanic ash can be very detrimental to human health, due to the harmful aerosols and poisonous gases the ash is made up of.
- The the International Civil Aviation Organization has records for 83 "encounters" between aircraft and volcanic ash between 1935 and 2008.
- Volcanic ash consists of fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions, less than 2 mm (0.079 inches) in diameter.
- The movement, spread and dispersion of volcanic ash clouds depends upon: • The altitude reached by the ash cloud (of primary importance).
- Exposure to volcanic ash can trigger asthma attacks and cause wheezing, coughing, and respiratory irritation in individuals with sensitive airways.
- These occur when a volcanic eruption creates an "avalanche" of hot ash, gases, and rocks that flow at high speed down the flanks of the volcano.
- A volcanic eruption as seen from space. Volcanic ash is the name given to the fine particles of igneous rock produced by a volcano.