Grand Canyon dangers -- altitude

Dropping over the Rim of the Grand Canyon, you enter an entirely foreign world. Both the North and South Rims are relatively high, and quite cool, even in the summer months. The Kaibab National Forest, on the North Rim, is a high, between 7000 and 8000 foot mountain, known as Buckskin Mountain. The North Rim is traditionally closed to vehicular traffic during the winter months because of snow and difficult weather conditions. The South Rim is lower, but still about 7000 feet above sea level.


This combination of altitude, heat and dryness is a real danger to those who, without proper preparation, leave the cushions of civilization on the Rim and drop into the Canyon.

First, the vast majority of people live well below 7000 feet. Altitude sickness, also known as acute mountain sickness commonly occurs above 2400 meters or approximately 8000 feet. See Altitude Sickness. However, symptoms of the condition can appear as low as 6,500 feet about sea level (2000 meters). Symptoms include headache, fatigue, stomach illness, dizziness, and sleep disturbance. Exertion aggravates the symptoms. In extreme cases, altitude sickness can be fatal.

I have lived much of my life at altitude, but have had acute symptoms of altitude sickness strike randomly, without warning. I remember one episode on Humphrey's Peak, the highest mountain in Arizona. I got an acute headache and had to lay down several times coming down the mountain to recover. I spent a lot of my summers up on the Colorado Plateau, I finally realized that my symptoms of fatigue were probably altitude related, going from near sea level in the desert to almost 6000 feet.

The Grand Canyon is definitely within the range of altitudes that can cause acute altitude sickness. When planning any hike into the Canyon, you definitely need to be aware of this possibility. While hiking out of the Canyon from Phantom Ranch, on one occasion, I could not figure out why I was hiking so slowly near the Rim. I finally realized that I had to breathe. So I would stop every 50 steps or so and breathe deeply. I finally began to move up the trail.

With all the other issues about hiking in the Canyon, this is one that is often overlooked.