Mount St. Helens blows off more steam

Seismologists watching Mount St. Helens in Washington state say the latest eruptions are just a lot of hot air.

On Wednesday morning, wisps of steam were rising from the volcano, which is found in the southwest region of the state.

The volcano released a white ash plume 7,600 metres into the air at 5:25 p.m. local time on Tuesday. It happened about one hour after scientists registered an earthquake of magnitude 2.0 beneath the mountain.

Jon Major, a U.S. Geological Survey researcher, said there was no danger to most people in the area.

Last October, the volcano sent up a 3,000-metre plume of steam and ash, lasting 24 minutes.

• FROM DEC. 24, 2004: Mount St. Helens regrows odd shaped top

Mount St. Helens grew a dome top the size of an 80-storey building in December, expanding at a rate never seen before by scientists studying the volcano. Infrared images showed fresh lava was rising at temperatures of almost 800 C.

Bill Steele of the Pacific Northwest Seismograph Network said a partial collapse of the dome in the crater may have triggered Tuesday's ash burst. He said he did not believe the explosion had increased the risk of a significant eruption.

When the dome formed, scientists said it would take 11 years before the volcano would erupt the way it did back in 1980, killing 57 people and covering towns more than 400 kilometres away with ash.

That eruption ejected more than a cubic kilometre of steam, ash, lava and rock, and reduced the height of the mountain by some 400 metres.

The explosion flattened every tree in an area the size of Toronto, and killed 57 people, 1,500 elk, 5,000 deer and an estimated 11 million fish. It also destroyed 200 homes, 47 bridges and 300 kilometres of highway.