Iceland's Grímsvötn volcano erupted on Saturday with an explosion that trumped last summer's Eyjafjallajökull eruption whose ash cloud shut down the airports of Europe. Dave McGarvie, a volcanologist at the Open University in Milton Keynes, UK, says that although Grímsvötn is spewing 10 to 100 times more ash into the atmosphere than Eyjafjallajökull, the ash particles are bigger and heavier and so more likely to fall back to earth quickly.
The prevailing winds are also helping to disperse the particles. Nevertheless, meteorologists say the ash cloud is due to reach the UK on Tuesday.
Image credit: http://earthobservatory.nasa.gov/images