After nearly 200 years of inactivity, Mount St Helens in Washington state in the USA erupted in May 1980. The explosion, which was estimated to have the equivalent power of 500 atomic bombs, killed 57 people in this sparsely populated area and had a devastating effect on local wildlife, destroying thousands of deer, elk and bear as well as countless birds and small mammals. For further details on the eruption look at the following website.
Here is an informative video on the eruption and a useful animation about how volcanoes are formed.
