REYKJAVIK, Iceland - An Icelandic volcano was flinging ash, smoke and steam miles into the air yesterday, dropping a thick layer of gray soot in an eruption far more forceful - but likely to make far less of an impact - than the one that grounded planes across Europe last year.

The country's main airport was closed and pilots were warned to steer clear of Iceland as areas close to the Grimsvotn volcano were plunged into darkness. But scientists said another widespread aviation shutdown was unlikely, partly because the ash from this eruption is coarser and falling to Earth more quickly.

The volcano, which lies beneath the ice of the uninhabited Vatnajokull glacier in southeast Iceland, began erupting Saturday for the first time since 2004. It was the volcano's largest eruption in 100 years.

The ash from Grimsvotn - about 120 miles east of the capital, Reykjavik - turned the sky black yesterday and rained down on nearby buildings, cars and fields. Civil protection workers helped farmers get their animals into shelter and urged residents to wear masks and stay indoors. No ash fell on the capital.

Scientists said the eruption was unlikely to have the same global impact as last year's eruption 80 miles away at the Eyjafjallajokull volcano, which left 10 million travelers stranded around the world.

"That was an unusual volcano, an unusual ash-size distribution and unusual weather pattern, which all conspired together to make life difficult in Europe," said

University of Iceland geophysicist Pall Einarsson.