Kahiltna Glacier Base Camp
Base Camp on the southeast fork of the Kahiltna Glacier is primarily where we fly climbers to climb the West Buttress, West Rib, South Buttress, Cassin Ridge along with Mt. Foraker, Mt. Hunter, Mt. Frances, Mt. Crosson and Kahiltna Dome.
During the climbing season there can be as many as 100 people at the Base Camp waiting to climb or fly out. It's quite a site to view dozens of colorful tents all set up and occupied by people from around the World.
The glacier landing area is about 2 miles long and 1/4 mile wide. There are several areas where crevasses open up into an abyss potentially thousands of feet deep.
A 3 degree down-slope is essential for take-off downhill. Snow, rock and icewalls tower 7000’ high and 1200’ wide from the landing area. More than once an avalanche has covered the landing area.
The Kahiltna Glacier is 7200’ above sea level and is a 36-mile-long glacier of the Alaska Range. It starts on the southwest slope of Mount McKinley near Kahiltna Pass - elevation 10,320 ft. Its main channel runs almost due south between Mount Foraker to the west and Mount Hunter to the east.
Denail - Mt. McKinley climb & weather information:
The West Buttress (63.06920°N / 151.0036°W) is the standard route climbers take to summit Denali and it provides access to the popular, but more technical, West Rib and Cassin Ridge routes. The most popular camps along the West Buttress are located at 7,200 ft (Base Camp); 7,800 ft; 9,500 ft; 11,000 ft; 14,200 ft; and 17,200 ft. Other camps are located at 12,500 ft and 16,000 ft, should only be used under ideal weather conditions as the 12,500 ft camp is vulnerable to avalanches and the 16,000 ft camp is very exposed to high winds. The 11,000 ft camp also experiences avalanches and serac fall, and care should be taken to avoid these two hazards when setting up camp. Above 14,200 ft, snow caves or igloos are usually constructed as a back up shelter in case bad weather moves in.
Total horizontal length of the West Buttress route is approximately 13 miles with about 13,500 ft of vertical gain. Between base camp and 11,000 ft, the route is relatively flat and the main hazards are crevasse falls. Above 11,000 ft, the route steepens to moderate slopes (35-45 degrees) alternating with flat benches and bowls. Equipment and supplies are typically carried by sled to 11,000 ft. Above 11,000 ft, gear and food are usually ferried between camps in two trips.
West Buttress expeditions average around 21 days. A 2-3 day supply of food and fuel should be left at base camp in case weather prevents planes from landing on the glacier (climbers have been stranded for as long as 2 weeks due to inclement weather). The following is a sample West Buttress itinerary during good weather:
Day 1: Land at Base Camp
Day 2: Rest day to organize gear and practice crevasse rescue
Day 3: Move to 7,800 ft camp
Day 4: Move to 9,500 ft camp
Day 5: Move to 11,000 ft camp
Day 6: Rest day
Day 7: Ferry loads to 14,200 ft camp, return to 11,000 ft camp
Day 8: Move to 14,200 ft camp
Day 9: Rest day
Day 10: Ferry loads to 17,200 ft camp, return to 14,200 ft
Day 11: Rest day
Day 12: Move to 17,200 ft camp
Day 13: Summit day
Day 14: Descend to 11,000 ft camp
Day 15: Descend to base camp, fly out
Mount McKinley is located in the subpolar low, a region where arctic air moving from the north converges with warmer air moving from the south at a latitude of 60 degrees (Denali is located at 63 degrees). This convergence creates a belt of unstable weather at this latitude. Associated with the subpolar low is a semi-permanent area of low pressure known as the Aleutian Low, located in the vicinity of the Aleutian Islands. Weather systems generated or passing through the Aleutian Low often take a straight path for the Alaska Ranges and hit Mt. McKinley with little warning. Mt. McKinley also has a reputation for streaky weather with long periods of either continuous bad weather or long periods of good weather. This explains why inexperienced climbers may reach the summit while veteran climbers don't make it back from their climb.
As a result of its proximity to the Aleutian Low, the weather on Denali is unlike the weather on any other major mountain in the world. Extreme cold is another hallmark of Denali’s weather and temperatures routinely fall to -40 F (-40 C). Unfamiliarity with McKinley’s weather is an underlying cause of many accidents. Weather patterns generally contain:
HIGH WINDS. Mt. McKinley undergoes long periods of clear skies and high winds, and these conditions are most often seen throughout the climbing season (April through June). Windstorms often come with little if any warning and are thus amongst the most feared weather patterns on the mountain. The first signs of increasing high winds are the appearance of lenticular cloud caps over the summit.
LOW PRESSURE SYSTEMS FROM THE GULF OF ALASKA. These are the cyclonic weather systems that sweep in from the southwest and vary in intensity, the strongest of which have been described as snow shedding hurricanes. During the more powerful storms, it is generally impossible to be above 14,000 feet.
LOW LEVEL MOISTURE. This occurs when warm, moist air migrates inland from the Pacific Ocean and creates a period of steady drizzle in the lowlands. During these periods, the top of the cloud layer occurs between 10,000 and 14,000 feet and conditions above these altitudes may be quite good. At other times, skies above 14,000 feet will be clear, but windy. Conditions on the lower mountain, however, tend to get sloppy and may even experience periods of rainfall and whiteout.
Sheldon Air Service pilots have over 34 years experience landing as the Kalhitna Glacier Base Camp.
Over the past several years we have noticed that the best time weather-wise to begin your climb of the West Buttress is the third week of May.