Ash clouds / Ashfall
Volcano Learning zone > Volcano Glossary
Volcanic ash consists of particles of rock less than 2mm in diameter. The ash comprises of violently disintegrated rock and magma during explosive eruptions. Although it may look like grey snow or flour it is essentially rock. Ash is abrasive and under the microscope has the same texture as crushed glass. It is abrasive and conducts electricity. When mxed with water it foms lahars or volcanic mudflows.Ash columns can rises 10 s thousands of feet into the atmosphere, blocking out the sun,causing aeroplanes to be grounded and eventually encircle the globe. Ash can cause global drops in temperature and spectacular sunsets.