Jan. 23 (UPI) -- One person was killed and at least 11 were injured after a volcano eruption possibly triggered an avalanche at a ski resort north of Tokyo, Japanese authorities said Tuesday.
One member of the Ground Self-Defense Force died and five others sustained injuries after being hit by the avalanche.
Several people were hit by volcanic rocks coming from the sky. Four were injured after stones from the eruption of Mount Kusatsu-Shirane hit a gondola lift, smashing the glass. The stones also hit the roof of a house where 100 people had already evacuated.
Experts said rocks can be thrown up to one mile away from the peak of the volcano and that there's a risk of further avalanches.
One person was reported missing but was eventually rescued from the snow, Japan Today reported.
Tokyo Electric Power Company said the ski resort lost power following the eruption, and the volcanic alert status was raised to a level 3, on a scale of 1 to 5.
"It's very difficult to predict smaller eruptions such as the one that occurred today," Yasuto Kuwahara, director of the Research Institute of Earthquake and Volcano Geology, said to the Guardian.
Kuwahara said the cause of the eruption was still unclear, as it wasn't yet evident if the blast was caused it by the interaction of magma or lava with water, or if it had been a phreatic eruption, which occurs when magma heats ground or surface water.
"There are many phenomena that precede a huge earthquake or volcanic eruption," Kuwahara said. "We are able to identify some of the precursors, but there will always be cases when eruptions happen very abruptly. That was the case this morning. It would have been very difficult to predict and order an evacuation."
The volcano, Mount Kusatsu-Shirane, towering at 7,900 ft, erupted at 9:59 a.m., the Japan Times reported.
Witnesses said black smoke filled the air as rocks fell from the sky. Moments later, the avalanche occurred.