American Alpine Jounrna and Accidents in North American Climbing

Missing Climbers — Assumed Fatal, Inadequate Equipment — Sleeping Bags and Fuel, Alaska, Mt. McKinley, Cassin Ridge

  • Accident Reports
  • Accident Year:
  • Publication Year: 2009


Alaska, Mt. McKinley, Cassin Ridge

Tatsuro Yamada (27) and Yuto Inoue (24,) both from Japan, were expected to return from a climb of the Cassin Ridge on May 22. With no sign of the men, the National Park Service began planning the search on May 23, although cloudy and windy weather initially kept all aircraft on standby. From May 24 to May 27, skilled observers flew a total of 33 hours of helicopter and fixed wing flight time in an aerial search effort. More than three thousand high-resolution photos of the search zone were captured during these flights. Analysis of the enlarged and enhanced images enabled a concentrated and effective search effort that continued at ground level after the conclusion of air operations on May 29.

On May 29, in light of the missing climbers limited supplies and the subzero temperatures, search managers concluded that the missing climbers survival was outside the window of possibility. Active field search operations were ceased with no pertinent clues being found to the whereabouts of Yamada and Inoue.


(The following was completed during operations by Daryl Miller, South District Ranger, Denali National Park & Preserve)

This Analysis addresses the practicability of suspending the ongoing Search and Rescue (SAR) activities currently being conducted on and in the vicinity of Mount McKinley from an active air search operation to a complete processing of digital photos. In lieu of the elapsed time since the commencement of SAR operations, the low possibility of survival at this time, and the risk of flying aviation support at high altitude attempting to press forward to increase the probability of detection of the search zone will only place additional personnel at an unwarranted risk.


1. Yuto Inoue and Tatsuro Yamada departed Kahiltna Base Camp on May 7 with approximately 5-6 days of food and fuel. They were last seen on May 9 at 7,800 feet on the junction of the North East fork by a French team and an Australian team camped near by intending to climb the West Rib. Since then, the only physical presence of the missing climbers has been tracks on the Kahiltna Peaks and high on the Cassin route. In addition, two sleeping bags and two journals, which were positively identified as belonging to both climbers, was found in their tent at 7,800 feet at the junction of the Northeast Fork.

Formal SAR activities then commenced on May 23, after the NPS was alerted on May 22 by the Japanese climbers Yusuke Satch, Fumitaka Ichimura, and Katsutaka “Jumbo” Yokoyama of the Giri-Giri #1 expedition. The three Giri-Giri #1 climbers were concerned about their situation on the Cassin, as they reported that Giri-Giri #2 had not returned to their base camp at 7,800 feet on the Northeast Fork of the Kahiltna.

On May 23, the NPS helicopter flew up the Cassin route and over the summit. Recent tracks that appeared to be fresh along with a campsite were seen by Giri-Giri #1 at 17,000 feet after they traversed from the Czech Direct to the Cassin Ridge at 16,000 feet. There were no other climbers that were registered to be on the Cassin Route before this team as well as during their climb time frame. The photos did reveal actual and probable footprints high on the mountain (up to 19,200 feet) and were very instrumental in allowing SAR forces to concentrate their efforts on key areas of the mountain. However, despite clear climatic conditions and two days of examining enhanced photos, no further discoveries of the climbers or their campsites were made.

The total elapsed time since the start of the climb also brings into question the issue of survivability. As stated, the two climbers had five to six days of food and fuel on the Cassin Route including four cylinders of compressed gas stove fuel for this route. Under optimum conditions one cylinder is good for up to six hours of use before becoming exhausted. On average, one cylinder would be used per day, but if managed correctly, it could be optimistically viewed that two cylinders could be stretched to three days. With this as the baseline, the four cylinders would have been used by the time both climbers reached high on the Cassin. This translates to eight to ten of days of fuel available allowing for the best-case scenario. Food supplies, as opposed to water, would not have as great a bearing on survivability for this short duration of time. Without an adequate fuel source to melt snow into water, climbers will rapidly become dehydrated. Also, with no sleeping bags and a high probability of debilitating frostbite, hypothermia, and fatigue, their chances of survivability will greatly be reduced. Generally a person cannot survive longer than three to four days without consuming fluids at these altitudes. This time period can be extended somewhat by eating snow, but this action hastens an individual’s drop into a hypothermic state and further depletes the store of calories available to maintain warmth. Based on these fuel consumption rates, both Climbers would now be on day-ten without being able to acquire the minimum quantity of water necessary to sustain life. The situation is further exacerbated by the extreme cold and dry conditions present on the top of the mountain (as well as not having sleeping bags). In a worst case scenario, fuel would have become exhausted five to six days into the climb, well after both climbers would have been high on the route and in a position where retreat would have been more difficult. In addition, the climbers had pre-positioned a cache at the 14,200-foot camp that was found on May 18 by Giri-Giri #2 with supplies undisturbed. The Giri-Giri#l team also found the Giri-Giri#2 sleeping bags at the 7,800- foot camp in their tent, suggesting that their situation was even worse and significantly lessens the probability of survival.

Continuing a high intensity search operation with multiple high-altitude sorties in the absence of any tangible clues as to the general whereabouts of the two climbers exposes rescue personnel to unwarranted risks. Multiple areas of the mountain have been searched by many different aerial resources without success. In addition, the poor prognosis of survival, coupled with the cold temperatures experienced during this period, further justifies that operations be scaled back.

The aerial search for live persons was officially suspended on May 30. If the bodies of Yuto Inoue and Tatsuro Yamada are discovered, a risk assessment will be conducted before an attempt is made to remove them. Limited search operations should be carried out only if by further examination significant clues are found either by digital photographs or by aviation methods, but only during a period of clear and calm weather.


The known facts make it difficult to comprehend how, after completing the difficult traverse of the Kahiltna Peaks and climbing the most difficult portions of the Cassin, these two talented climbers would run into difficulty on a considerably less technically demanding section of the route. Early May in the Alaska Range is no doubt cold; however, there were not any known significant weather systems that caused problems for any other climbing expeditions high on the mountain in this timeframe.

Though there are many different strategies and styles climbers can employ to undertake the more technically demanding routes, it is critical that all parties carefully consider what equipment can be left behind and what equipment is critical for sustaining the needed strength and stamina for the technically demanding, high altitude, arctic routes of the Alaska Range. (Source: John D. Leonard and Daryl Miller, Rangers, Denali National Park)

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