Dozens of hikers were stranded Saturday on the slopes of an erupting Japanese volcano that has reportedly left more than 30 people seriously injured.
Ash, rocks and steam continued to spew from Mount Ontake more than nine hours after it sprang violently to life as around 250 people were trying to scale its peak.
“I first thought it was thunder as I heard a bang and another bang, two or three times,” a trekker told public broadcaster NHK. “Then volcanic dust fell noisily.”
Amateur cameraman Keiji Aoki told Jiji Press: “It was tremendous. I prepared for death when I got caught in the dust under a pine tree.”
A suffocating blanket of ash up to 20 centimetres (8 inches) deep covered a large area of the 3,067 metre (10,121-foot) volcano, trapping climbers and forcing up to 150 into mountaintop shelters at one point.
Around 230 people have now reached the bottom but around 40 are trapped at the summit where they will spend the night in shelters, local media reported.
Aerial footage of Mount Ontake showed several cabins smothered with the thick dust, some with windows that appear to have been shattered by the force of the eruption.
NHK said 32 people had been seriously injured, including more than 10 who were unconscious.
The eruption came on a busy autumn day on a mountain popular among hikers at this time of year.
The meteorological agency forecast further eruptions, warning that volcanic debris may settle within four kilometres of the peak.
The agency also placed restrictions on access to the mountain, while calling on local residents to remain on alert as an eruption could shatter windows miles away.
The last significant eruption of Mount Ontake, which straddles Nagano and Gifu prefectures in the centre of the country, was in 1979 when it expelled more than 200,000 tonnes of ash, according to local media.