At 10 A.M. on Tuesday, May 28, climbing guides Keith Sidle and Chad Ray stood at 18,400 feet, near a striated rocky outcrop called Zebra Rocks on Denali. The two were leading an expedition of four clients up the famed West Buttress route with the Alaska Mountaineering School, and they marveled at the clear skies and favorable conditions.

　　That day was about as good as conditions get on Denali, Sidle told Outside.

　　Up ahead, the two saw a figure walking towards. The man was Muhammad Illaham Pak Am Ishak, 47, one of three members of a climbing team from Malaysia. Sidle quickly noticed that something was wrong with Ishak.

　　His right hand was ungloved, with what appeared to be full-thickness frostbite, Sidle said. He was carrying a dead SAT phone.

　　Ishak asked the two to call rangers and request a helicopter rescue, and he then described a harrowing scene unfolding further up the mountain. His two climbing partners were hunkered just below the summit on a section of the mountain called the Football Field, he said, and both were exhausted, hypothermic, and unable to descend. After a brief conversation, Ishak continued downward. Sidle and Ray got on a radio and communicated the SOS. Then they and their clients continued their ascent, eyes peeled for Ishak’s two partners.

　　The interaction marked the beginning of a dramatic stretch on Denali during which rangers and guides attempted to rescue the trapped Malaysian climbers.

　　A Series of Miscalculations

　　Every spring, Denalis West Buttress route attracts hundreds of mountaineers from around the globe. Some are chasing the Seven Summits challenge—ascending the highest mountains on each of the continents. Denali is among of the toughest of the seven, due to its vertical rise from base camp and position on the 63rd parallel, just a few degrees shy of the Arctic Circle. Temperatures near the 20,310-foot summit can plunge well below zero, and it’s often buffeted by extreme winds.

　　Ishak was climbing Denali alongside Zulkifili Ajoy Bin Yusof, 37, and Zainudin Deeno Lot, 47. The three were members of Alpine Club Malaysia, a climbing organization based outside of Kuala Lumpur, with a focus on helping its members ascend the Seven Summits, in addition to reaching the North and South Pole, a challenge collectively known as the Explorer’s Grand Slam. A club spokesperson told Outside that the organization is dedicated to aspiring climbers in general, but obviously the biggest prize is the Seven Summits.”

　　After the Denali mission, Lot and Ishak planned to ascend 16,050-foot Mount Vinson in Antarctica to complete the seven. Both Lot and Ishak had been to Denali twice before, once guided and once unguided, but neither had reached the top. Lot told Outside that he has been a mountaineer for 30 years and has coached climbing since 2012, and he believes the group had enough experience for the expedition.

　　“My training in Malaysia also climbing many other peaks like the Seven Summits gave me confidence to survive on Denali, he said. “I used all my knowledge and experience to stay alive.”

　　But rangers and guides say the Malaysians made several errors that led to their dire situation. According to Tucker Chenoweth, Denali National Parks South District ranger, the trio pushed for the summit from a campsite on a ridge at 16,000 feet. Normally, groups stay in high camp at 17,200 feet before climbing to the summit. Its uncommon to leave from this camp for a summit push because it makes for a very long, tiring day, Chenoweth said.

　　Lot told Outside that his party left their high camp at 5:00 A.M. and reached the summit shortly before midnight on Monday, May 27—a summit push of 19 hours. Shortly after reaching the top, Bin Yusof became hypothermic, he said, and his two companions attempted to warm him up, hugging the man and wrapping him in emergency blankets. The trio spent nearly an hour on the summit ridge, before Bin Yusof asked the others to call for an evacuation.

　　NPS received an SOS from the team at 1 A.M. on Tuesday. Two hours later, another SOS message came in: the trio would descend to a section of the mountain called the Football Field—a relatively flat swathe of glacier at 19,600 feet—and await an air rescue.

　　At noon on Tuesday, the Alaska Air National Guard flew a HC-130 airplane over the area, and spotters saw two figures in the snow.

　　A Bad Scene at 19,000 Feet Sidle and Ray found the two stricken climbers on Pig Hill, a steep incline just below the summit, at 1:30 P.M. The scene looked grim: Lot was laying face down on his pack, with his head pointed uphill. He wasnt moving. A rope was attached to him extending for about 50 feet, ending in a figure-eight, Sidle said.

　　Further uphill was Bin Yusof, who was standing, but appeared to be in worse shape. Bin Yusof was disoriented and acting erratically. Sidle believes he was suffering from high-altitude cerebral edema—brain swelling due to lack of oxygen—which can be fatal. He was stumbling around, and his hands were very frostbitten, Sidle said. He was just in his liner gloves with his mittens dangling from his wrists.”

　　As the party approached, Lot sat up and was coherent, rattling off basic information on request: the date, his name, nationality, and location on the mountain. Sidle and Ray carried several doses of the corticosteroid dexamethasone, and they administered the drug to both men—it is a common treatment for altitude sickness. They radioed rangers down the mountain, and then placed the two Malaysians in a two-man bivouac sack. They gave them hot water and food.

　　Ray and Sidle, who have 15 years of collective guiding experience, believed that if the men were incapable of descending under their own power. The downward climb from Denali includes a sheer and icy slope called the Autobahn, where fatal falls are common.

　　Trying to move non-ambulatory patients in semi-technical terrain when you have clients, at that elevation, it’s not really an option, Sidle said.

　　Lot told Outside that Ray and Sidle did everything within their power to help him and Bin Yusof. “Above 5,000 meters [16,404ft], you’re on your own,” he said

　　After staying with the Malaysian climbers for approximately an hour, Sidle and Ray knew they had to move. One client was suffering from the altitude—Sidle took the climber and another in their party back down. Ray proceeded to the summit with the others. They stopped with the Malaysians again on their way down, giving the men a puffy parka.

　　As Ray departed around 5:00 P.M. another party approached. Matt Park of Mountain Trip Guides, one of two guides helping a solo climber, stopped with the Malaysians to care for them. Down below, rangers attempted to get a helicopter into the air. But as evening grew late and temperatures began to drop, Park knew that he was also going to have to leave them. He dug a snow trench to provide them with shelter from the wind, and then climbed back down to the high camp.

　　“He said, ‘You wait here, tomorrow morning the rescue will come and fetch you guys, Lot said. Take care and hold on until then.’”

　　Three Days of Wind

　　Conditions on the top of the peak were ideal on Tuesday, May 28, but further down, a dense layer of clouds kept helicopters from punching through to higher elevations. Chenoweth said NPS rangers launched multiple attempts to fly above high camp that afternoon, but failed each time. The upper mountain was in good shape, Chenoweth said. But everything below was socked in with a solid cloud ceiling.” Eventually, the rescue helicopter flew off the mountain to evacuate two frostbitten climbers—members of a different party—from Camp IV at 14,200 feet.

　　On Wednesday, rescuers awoke to dense clouds and violent winds—conditions that again grounded helicopters. Attempts to contact the Malaysians failed until 10 P.M. that night, when five messages came to rangers in rapid succession. The communications said both men were fighting for their lives, and their inReach battery was nearly dead.

　　Another day of foul weather grounded flights, but late on Thursday night, a helicopter was able to fly to the Football Field at 10:30 P.M. It was too windy to stage a rescue, but the crew dropped a duffel bag of gear and provisions 100 yards from the trench Park had dug. The pilot saw a lone person—later identified as Lot—waving.

　　Finally, after three days attempting to reach them, a rescue helicopter was able to fly to the Football Field at 7 A.M. on Friday, May 31. Rangers plucked Lot from the mountain with a short-haul rope. But by then Bin Yusof was dead. Rangers believe he succumbed to the elements on Wednesday, May 29. Officials have yet to reveal his cause of death, but officials told Outside that it was likely a combination of high-altitude cerebral edema and hypothermia.

　　“I used all my knowledge and experiences for the past 30 years to survive,” Lot said. “But to be honest, if the rescue did not come on Friday, I would have followed Bin Yusof into death.”

　　Lessons to be Learned

　　Lot and Ishak were both treated for frostbite and released from a hospital in Anchorage. When Outside spoke with Lot on Tuesday, June 11, he was still in the United States, preparing Bin Yusof’s body for transport home.

　　Sidle told Outside that he helped Lot from the helicopter on Friday morning after his rescue, and that Lot replayed scenes from the ordeal and answered questions with ease.

　　“The fact that he survived at 19,600 feet for four nights and was still all there, coherent, that’s pretty incredible,” Sidle said.

　　Lot said he was still proud of his teams achievement on the peak.

　　“We are the first team from Malaysia to do a self-guided climb on Denali,” he said. “Doing this remarkable adventure, we can proudly say Malaysia also has potential climbers that can stand tall with other world class mountaineers.

　　He still plans to take on Mount Vinson to complete his Seven Summits, and believes that his ordeal on Denali should count toward his goal. “I consider staying for five days and four nights up there as replacement for my descent,” he said.

　　In the wake of the incident, both rangers and guides believe there are lessons climbers can learn from the rescue. Sidle said the gear the Malaysians had was below standards for the extreme environment. Their pants and jackets were pockmarked with duct tape to fix tears. Their boots, he said, were totally fubar, with one sole delaminating entirely when the guides removed their crampons to bundle them into the bivy sack. One climber had a pair of crampons with a homemade toe-bail. They didnt have any contingency gear between them either, like a sleeping bag or bivy sack, Sidle said.

　　The Malaysians were climbing without a guide, which would have earned them an accolade in the Malaysian Book of Records. This was a key motivation for the team, Alpine Club Malaysia’s spokesperson said. But guides often push climbers to adhere to strict timetables on ascents, to limit their exposure to extreme altitude and cold.

　　Lot acknowledged the teams mistakes, but also attributed the tragedy to elements beyond his control—luck and weather. “As a Muslim, I believe in God,” he said. “Nothing can change His plans for us.”

　　On Denali, small miscalculations can quickly add up to a disaster, Sidle said. Whether you woke up a little later, you moved a little slower, the weather was a little worse, your equipment wasn’t as good as you thought. You can almost never trace an accident to a one-off mistake, he said.

　　Chenoweth said the tragedy and rescue is another reminder of the dangers on Denali. Rescues on the peak place the lives of others in danger, and climbers hoping to reach the summit should not be driven by that singular goal. Getting up and down safely is more important. “Climbing a mountain like Denali, you’re spending 15 to 22 days in this amazing, remote wilderness,” Chenoweth said. “If you’re not here for that, and you just want to get to the top, it really shows in your decision-making.”