TOKYO (AP) — At least 11 people were injured when a volcano erupted in central Japan today, catching mountain climbers by surprise and trapping more than 250 people.

Authorities say seven of the injured were unconscious.

With a sound likened to thunder, Mount Ontake spewed large white plumes of ash high into the sky and sending people on the mountainside fleeing, covering some in ash.

Authorities say more than 250 people were trapped on the mountain and a nearby peak in areas that were dangerous to approach, though some had decided to try making their way down as sunset approached.

In a YouTube video shown on Japanese TV, shocked climbers can be seen moving quickly away from the peak as an expanding plume of ash emerges above and then engulfs them.

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