What happens when a volcano erupts

Volcanoes release the pressure that builds up inside the Earth, when pressure builds up, eruptions occur. Magma shoots up through the volcano and flows down its sides. When magma flows out of a volcano we call it lava. Fresh lava can be as hot as 1,250° C, glowing red or white as it flows.
Eruptions can cause mudslides, avalanches, and floods, some volcano eruptions have even knocked down entire forests and triggered tsunamis and earthquakes.
largeAs they erupt, volcanoes spew huge clouds of volcanic ash into the atmosphere. Ash clouds can cover hundreds of miles, creating problems for aeroplanes and changing weather patterns. Volcanic ash can also damage the lungs and cause other problems for those who breathe it in.