Ash

When a volcano erupts, it will eject a wide variety of material into the air above it. The large fragments of material travel a relatively short distance from the volcano, however fine material, which is made up of volcanic glass, rock, and crystal particles, can travel upwards and outwards over great distances. Its consistency may range from grains of sand to a powder similar to talcum. Clouds of ash can be thick enough to block sunlight, and can travel  for hundreds of kilometres on the wind. Ash clouds can also generate powerful electrical fields producing intense and frequent lightning discharges. ⁴⁷¹⁷

Windborne particles may have acid coatings that can irritate skin, ³⁸³⁰ lungs and eyes. Volcanic ash poses a threat to jet engines and may result in the closing of airports and disruption to travel and transport of goods. When it settles on land it may pose a significant hazard to lifelines such as roading, water and wastewater and electrical networks. Damage to nearby agriculture, crops and other industry can be considerable. Ash may pollute water supplies and thick deposits of ash on roofs may cause them to collapse.

Last updated at 10:50AM on February 8, 2018