The Denali climbing season is imminent. The peak’s high latitude, extreme altitude, and arctic climate present hazards that challenge even the most experienced climbers.

Our April “Prescription” is a Denali National Park accident summary, accompanied by an altitude illness report from the peak’s most popular route. While mishaps involving crevasses, avalanches, and falls plague climbers every year, altitude illness is the most preventable cause of incidents on Denali.

This following summary and report will be published in the upcoming 2024 Accidents in North American Climbing. The book will also include a special feature titled Acclimatization and High Altitude Illness, written by Dr. Peter Hackett and ANAC Senior Editor, Dave Weber.

Denali National Park Accident Summary

Denali mountaineering rangers treated a total of 33 patients during the 2023 climbing season in the Alaska Range. The following list provides a breakdown of the diagnoses* from this past rescue season:

• Traumatic Injury – 11 cases (includes one facial laceration, three shoulder injuries, one traumatic brain injury, one case of fractured ribs, one neck injury, and four patients with various musculoskeletal injuries)

• Frostbite - 11 cases

• Medical - Six cases (includes two hypothermia, one diverticulitis, one spontaneous pneumothorax, one possible case of anxiety, and one case of anaphylaxis)

• High Altitude Cerebral Edema – Three cases

• High Altitude Pulmonary Edema – Three cases

*Some patients had multiple diagnoses resulting in a higher number of diagnoses than the total number of patients.

Twenty-one patients required helicopter evacuation from Denali National Park. Three patients were evacuated by NPS Rangers on the ground and nine patients self-evacuated after receiving treatment.

There were three mountaineering-related deaths in the Alaska Range during the 2023 climbing season, with an additional post-evacuation fatality. One occurred when a solo skier was caught in an avalanche. Two fatalities occurred due to a fall from the Moose’s Tooth in the Ruth Gorge. On Denali’s West Buttress, one climber suffering from severe altitude illness was treated and evacuated, but subsequently died in hospital (see below).

While some accidents are difficult to predict and prevent, many of these medical illnesses and traumatic injuries are preventable with prudent decision-making and a reasonable ascent profile during climbing expeditions. Additional information regarding the prevention, recognition, and treatment of common mountain medicine maladies can be found online in the Denali mountaineering handbook: https://www.nps.gov/dena/planyourvisit/part2medicalissues.htm

(Source: Denali Mountaineering Rangers.)

Alaska | High Altitude Cerebral Edema

Denali, West Buttress

On May 31, an independent expedition camped at 14,200-foot camp notified rangers via radio that one team member, a twenty-four-year-old Coloradan, had an altered mental status. The team stated that they had been dropped off by fixed wing aircraft at Base Camp (7,200 feet) on May 27. Immediately upon landing, they embarked on the West Buttress route, reaching 14,200-foot camp a day and a half later on the evening of May 28. The team stated that upon reaching camp, all members were feeling “ok.” On the afternoon of May 30, teammates alerted NPS rangers that the Coloradan—after reportedly feeling “groggy” with a slight headache—began exhibiting severe symptoms of high-altitude cerebral edema (HACE) and pulmonary edema (HAPE). A second team member was experiencing moderate symptoms of HAPE.

Weather conditions were not flyable on the night of May 30. A team of NPS rangers and volunteer patrol members performed 18 hours of advanced life support on the unresponsive HACE/HAPE patient throughout the night. Treatment included a hyperbaric chamber, medications, supplemental oxygen, and mechanical breathing assistance.

On the morning of May 31, the patient was evacuated by helicopter. An Air National Guard Pararescue Specialist from the 212th Rescue Unit served as the medical attendant. The patient was flown to Talkeetna and was then transferred to a LifeMed air ambulance for advanced care. Unfortunately, the patient succumbed to the effects of HACE/HAPE in the hospital.

ANALYSIS

As many do, this team made the assumption that living at a relatively high altitude (5,000 feet) and maintaining a high level of fitness would prepare them adequately for rapid elevation gain. This incident is an extreme example of the inaccuracy of this assumption. Even those who live at elevations far higher than 5000 feet may not be adequately acclimatized for a climb up Denali. The human body begins losing its altitude adaptions in a matter of days, an interval that many climbers spend while traveling to Alaska and Base Camp.

The Wilderness Medicine Society recommends that while ascending above an altitude of 9,000 feet, climbers should limit their daily elevation gain to no more than 500 meters (~1,650 feet) between sleeping locations. They also recommend spending an extra night at the same elevation for every 3,300 feet of elevation gained.

Every season, many extremely fit climbers attempt Denali. While physical conditioning is an important factor in risk management and success, the overestimation of fitness as a determinant factor gets many of these same climbers into trouble.

Unfortunately, an individual’s degree of fitness does not determine whether or not they will suffer altitude illness. Only a conservative ascent profile and proper acclimatization will prevent this.

(Source: Denali Mountaineering Rangers.)

THIN AIR ON DENALI: THE EDITOR’S STORY

I climbed the West Buttress in 2003 as an intended acclimatization for another route. Looking back, I fit the profile of the individual involved in the above accident—I lived in Colorado at above 5,000 feet, I was fit, and I trained consistently prior to the trip. While I knew that the West Buttress was technically moderate, I also knew that the relative atmospheric pressure of the 6,190 meter (20,310 feet) summit was the equivalent of over 7,000 meters in the Himalayas.

We made fairly rapid progress and my fitness served me well on the way up to14,200-foot camp. When we arrived, I felt “off.” Having spent considerable time in the Himalayas climbing above 6,000 meters, experience told me that I could use a few restful days and nights to acclimatize. My partner however, was feeling spry and was eager to carry on to the next higher camp at 17,200 feet. He wanted an advantageous position for a summit bid.

Sometimes you get lucky—the ongoing debate on whether to immediately go higher or stay put, ended when a storm rolled in. By the time the weather cleared, we were rested and acclimatized enough to skip 17,200-foot camp and successfully dash to the summit and back. The forced delay had paid off, as did the solid path beaten into the fresh snow by the dozens of summiteers, whose ranks had swollen during the days of bad weather. Had we pushed higher sooner, I may have gotten altitude illness. This would have negated a summit attempt and/or endangered myself and my partner. This episode was a reminder that mountains do not care how hard you trained, nor how tight your schedule is.

—Pete Takeda

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