Japan Versus the Volcano
Hunt for survivors ends on ash-covered Mount Ontake
The major rescue operation on Mount Ontake—the 10,062-foot volcano that erupted in Japan last month—is now over.
It was a quick response and an example of Japanese disaster relief work at its best. But it wasn’t easy—far from it. The troops and civilian responders had to move fast and light, while risking injury or death in the hope of reaching trapped climbers before time ran out.
The Japan Self-Defense Forces dispatched 600 troops, 130 vehicles and 17 aircraft to search for mountaineers lost in the ash, rubble and poisonous gases. But after weeks of searching, and with snow on the ground amid thick layers of volcanic debris, the military had no choice but to end the mission.
The Sept. 27 eruption claimed 56 lives—similar to the Mount St. Helens eruption of 1980, which inflicted 57 deaths. Seven individuals remain missing on Mount Ontake, but the search for them is over until spring.
The mission began on the day of the eruption when Nagano Gov. Shuichi Abe requested assistance from the local 13th Infantry Regiment based out of Matsumoto. Within 45 minutes, a Blackhawk helicopter from the 12th Helicopter Regiment was in the air, scouting the conditions around the volcano.
The first troops on the ground were a 40-member “FAST Force.” They left Camp Matsumoto within hours of the eruption.
Japan’s Ministry of Defense unveiled the FAST Force concept a year ago. The full title is quite a mouthful in Japanese, but its catchier official name stands for First Action Support Force.
Previously, Japan’s military would wait for a request from local governments before dispatching troops. Under the FAST Force concept, rapid reaction teams can leave for affected areas within an hour of a disaster prior to receiving a formal request.
This allows them to get to work immediately. The FAST Force was more than two hours away, and every moment mattered to those trapped on the mountain.
By the end of the first day, 180 troops were in position on the mountain as reinforcements gathered at the nearby Camp Matsumoto. The initial response force also received dedicated air support from four helicopters—two Blackhawks, a Cayuse and a Chinook.
Golden 72 hours
It was a beautiful morning for climbing. It was Saturday, Sept. 27—and climbers reported sunshine, a cool mountain breeze and blue skies.
A few minutes before noon, magma within the volcano’s cone suddenly flash-heated ground water mixed with the mountain’s porous rocks and soil. The reaction sparked a steam explosion that propelled rocks, ash and gases onto the mountainside.
For the climbers close to the summit, the greatest danger came from the flying debris. But hard cover was no guarantee of safety, as volcanic gases threatened to suffocate those in otherwise sensible shelters.
Local police and firefighters led the initial rescue efforts, concentrating on the 230 climbers who headed down from the summit to safety. Climbers who survived the initial eruption tweeted updates, photos and videos of their descent to safety. Many climbers took shelter from the falling debris and ash clouds in cabins dotted along the mountain paths.
Shortly before 5:00 a.m. the following day, 170 troops set out along two trails—risking injury or death—to find survivors trapped at the summit.
Dressed in green fatigues, the military’s rescue teams were immediately identifiable on the mountainside, now painted in matte-grey from the ashes.
Fortunately, good news came quickly. An hour into the operation, a Black Hawk helicopter hoisted two survivors from a small cottage on the rim of the caldera.
Troops arrived at the summit at 10:40 a.m. and began searching cabins where survivors might have holed up. Conditions were terrible. Ash piled 20 inches deep in some places. The volcano was still spewing out smoke, steam and gas. At two o’clock in the afternoon, volcanic gases forced the rescue teams to stop. They descended the mountain—taking four dead climbers down with them.
Helicopters winched away the last survivor at 5:25 p.m., bringing the total to 23 survivors in the first 30 hours. Search and rescue missions operate on the assumption that the first 72 hours are critical for saving lives.
The troops didn’t know it yet, but they wouldn’t rescue anyone else for the remaining 17 days.
The initial deployment on Sept. 28 chose speed over utility. Civilian firefighters told Asahi Shimbun they moved so fast, they had to leave their shovels behind. Instead, they used their hands to dig through the ash.
The responders prioritized survivors first. There was only enough time to tag bodies and press on. They’d collect the dead later.
The next day was little different. As far as the troops on the ground knew, there could still be survivors on the mountain, as they were still within the golden 72-hour period when survival chances were high.
Around 270 troops searched along three mountain trails and called in Black Hawks to transport eight bodies from near the Ichinoike depression in Ontake’s crater. Ichinoike is 9,777 feet above sea level. When water fills this depression, it becomes a pond—the highest lake in the country. It was now a muddy swamp of ash.
Volcanic gases were a constant threat, repeatedly forcing search parties back down the mountain. Constant exposure to even low levels of hydrogen sulfide—which smells like rotten eggs—can cause headaches and nausea.
Gases weren’t all the rescue teams had to contend with. “The area of operations is at high-altitude so it’s difficult to breathe, and the muddy volcanic ash saps away your strength,” Maj. Hidefumi Terada of the 30th Infantry Regiment told Yomiuri Shimbun.
At Mount Ontake’s summit, over 10,000 feet above sea level, the body’s blood oxygen saturation level reaches about 90 percent. This creates conditions ripe for hypoxia—otherwise known as altitude sickness.
The hypoxia threat multiplied with heavy physical work. The rescue teams found bodies buried in rubble and ashy mud, which required strenuous digging and lifting.
With the fumes and ash, rescue workers had to work while wearing protective respirators—which were in short supply. These tough conditions put more strain on their lungs.
The search teams also ascended the mountain quickly to make the most of the daylight and good conditions. This left little time to acclimate to the lower oxygen levels at such high altitudes.
Volcanic seismic activity complicated the search effort. On Sept. 30, the Self-Defense Force team ended their search because of near-continuous tremors. The golden 72-hour period had already passed. The rescue teams now became undertakers.
On Oct. 1, helicopters transported 35 tagged bodies from the mountain—the most bodies recovered on a single day. That brought the tally to 47 fatalities. Two days later, the Nagano Prefecture Police announced that all but one of died from falling debris striking their heads, necks, backs and hips. The other died from burns to the respiratory tract.
Search teams found more than 30 bodies at a shrine and hut near the mountain’s summit. Another 10 people died while walking along a trail that offered no protection from the rocks that would have rained down on them.
The recovery mission also faced inclement weather. Heavy rain and wind severely limited the number of days available to the search efforts. Incoming Typhoon Phanfone caused further delays, as did Typhoon Vongfong a week later.
But then came the cold snap. When relief efforts restarted on Oct. 15, snow covered the summit of Mount Ontake. The forecast predicted even more rain. This string of bad weather made it difficult to get helicopters up the mountain, and made it dangerous to climb.
On Oct. 16, the military ceased its operations around Mount Ontake.
Local authorities confirmed the identities of the 56 bodies retrieved during the 19-day civilian and military relief effort. Seven people are still missing and are presumed dead.
The Ground Self-Defense Force took 19 family members of these missing individuals aboard a Chinook helicopter for a final look at the snow-covered peak. If their loved ones are still on the mountain, they will have to wait until spring next year.