OTAKI, NAGANO PREF. - Police confirmed Sunday night the deaths of four of the 31 people found unconscious near the peak of Mount Ontake earlier in the day, one day after the eruption on the Nagano-Gifu prefectural border.
The remaining 27 are all feared to be dead, though officials have yet formally confirmed the deaths of any of them.
The 31 were found in a state of cardiopulmonary arrest when rescue operations resumed Sunday morning. At least another 40 people were injured during Saturday’s sudden eruption.
Facing poisonous gases and fearing another eruption, rescue workers were able to transport just four of the 31 victims to the foot of the mountain by Sunday night. The four were officially pronounced dead when they arrived at the bottom of the mountain.
About 10 of the 31 victims were found lying near the spot where smoke was billowing out of the side of the volcano and could not be rescued.
Additional search and rescue operations will be resumed Monday morning.
The victims had been climbing the volcano when it erupted just before midday Saturday.
Hundreds of people, including children, were stranded on the mountain after it erupted without warning, sending ash cascading down its slope for more than 3 km. Most of them made their way down the mountain on Saturday evening.
According to the Meteorological Agency, the eruption was still continuing as of Sunday night. The government the same day maintained the alert level at 3 on a scale to five, meaning climbers were prohibited from approaching the mountain.
When the 3,067-meter Mount Ontake erupted, it sent smoke plumes extending up to 10 km high, and smaller eruptions continued overnight.
While data had shown evidence of volcanic quakes in the area in mid-September, there were few other indications that an eruption might be in the offing, making it difficult to predict, according to the Meteorological Agency.
Japan is habituated to periodic volcanic eruptions, being one of the world’s most seismically active nations, but they have caused no fatalities since 1991, when 43 people were killed by a pyroclastic flow at Mount Unzen in Nagasaki Prefecture.
When rescue efforts resumed Sunday, 24 people were evacuated off the mountain. Of the 24, some were picked up by a Self-Defense Forces helicopter.
TV footage showed one soldier descending from a helicopter onto an ash-covered slope and hoisting a stranded mountaineer to safety. The SDF has deployed seven helicopters and 250 troops to the area. Police and fire departments are also taking part in the rescue effort.
Late Saturday, domestic media said one woman had been killed on the mountain but those reports were later withdrawn.
More than 40 climbers were forced to shelter in lodges overnight due to poor visibility from the volcanic ash. Some began to descend the mountain on their own Sunday morning.
With a sound likened to thunder, the volcano erupted on a clear autumn day, spewing large white plumes of gas and ash high into the sky and blanketing the surrounding area in ash.
One witness told NHK that the eruption started with large booms. In a video posted on YouTube, shocked climbers can be seen fleeing from the peak as an expanding plume of ash emerges above and then engulfs them as it churns down the mountainside.
Many of those who made it down emerged with clothes and backpacks covered in ash. They reported being engulfed in total darkness for several minutes.
Mikio Oguro, an NHK journalist who was on the slope on an unrelated assignment, told the station that he saw massive smoke coming out of the crater, blocking sunlight and reducing visibility to zero. Oguro said he and his crew had to use headlamps to find a lodge.
“Massive ash suddenly fell and the entire area was totally covered by it,” he said by phone. “My colleagues later told me that they thought they might die.”
The mountain, which is popular with tourists, particularly in the fall, last experienced a major eruption in 1979, when it expelled over 200,000 tons of ash. It also underwent a minor eruption in 1991 and caused multiple volcanic quakes in 2007.