America's National Parks and Road Trip Planning Find Your Park Road Trip Activities Nature

Grand Canyon National Park Smart Hiking

Smart Hiking in the Grand Canyon during the summer months presents unique hazards, the result of extreme heat and some of the steepest and most rugged terrain on Earth. Every year, scores of unprepared hikers, lured by initially easy downhill hiking, experience severe illness, injury and death from hiking in the canyon. Consequently, for both public and employee safety, the National Park Service urges SPECIAL CAUTION for all hikers during the summer months. Be aware that efforts to assist you may be delayed during the summer months due to limited staff, the number of rescue calls, employee safety requirements, and limited helicopter flying capability during periods of extreme heat.

Rangers take heat exhausted hikers to the hospital every day during the summer. One of the most common heat exhausted patients is male and in his twenties. Do not rely on physical strength to get you through the canyon. Hiking intelligently will take you much farther. For your safety, plan your trip to avoid hiking in the hottest part of the day. When inner canyon temperatures are extremely high, access to inner canyon trails may be restricted to early morning and evening. Information on trail restrictions and trail closures is available at (928) 638-7888 (press 1-3-1).

Note: Due to extreme cold water and swift currents, DO NOT attempt to swim in the Colorado River.

While many hikers have experience in the mountains, the inner canyon is a desert. The hot, dry environment and the hiker's exertion combine to complicate the effects of fatigue. During the summer season when inner canyon temperatures routinely exceed 100F (40C), dehydration is common and can lead to heat exhaustion. More serious illnesses associated with desert hiking are heat exhaustion, hyponatremia, heatstroke, and hypothermia: the hazardous H's!

HEAT EXHAUSTION Is the result of dehydration due to intense sweating. Hikers can lose one or two quarts (liters) of water per hour. Symptoms are pale face, nausea, cool and moist skin, headache, and cramps. To treat, drink water, eat high-energy foods, rest in the shade, and cool the body. HEATSTROKE Is a life-threatening emergency where the body's heat regulating mechanisms become overwhelmed by a combination of internal heat production and environmental demands. Symptoms include flushed face, dry skin, weak and rapid pulse, high body temperature, poor judgement or inability to cope, and unconsciousness. The heatstroke victim must be cooled immediately! Continuously pour water on the victim's head and torso, fan to create an evaporative cooling effect, move the victim to shade, and remove excess clothing. The victim needs evacuation to a hospital. Someone should go for help while attempts to cool the victim continue.

HYPONATREMIA (water intoxication) Is an illness that mimics the early symptoms of heat exhaustion. It is the result of low sodium in the blood caused by drinking too much water, not eating enough salty foods, and losing salt through sweating. Symptoms are nausea, vomiting, altered mental states, and frequent urination. To treat, have the victim eat salty foods. If mental alertness decreases, seek immediate help!

HYPOTHERMIA Is life-threatening emergency that can occur in any season. The body cannot keep itself warm, due to exhaustion and exposure to cold, wet, windy weather. Symptoms are uncontrolled shivering, poor muscle control, and careless attitude. To treat, put on dry clothing, drink warm liquids, warm victim by body contact with another person, protect from wind, rain, and cold. Avoid hypothermia by checking at Canyon View Information Plaza or Backcountry Information Center for latest weather and trail conditions, taking layered clothing for protection against cold and wet weather, eating frequently, replacing fluids and electrolytes by drinking before feeling thirsty, and avoiding exposure to wet weather. Drink (and eat) Often YOU SWEAT AROUND 1/2 TO 1 QUART OF WATER AND ELECTROLYTES FOR EVERY HOUR YOU WALK IN THE HEAT. This fluid/electrolyte loss can even exceed 2 quarts per hour if you hike uphill in the direct sunlight and during the hottest time of the day. Because inner canyon air is so dry and hot, sweat evaporates instantly, making its loss almost imperceptible.

Do not wait until you are feeling thirsty to start replacing these fluids and electrolytes. By the time you feel thirsty, you are already dehydrated. Even this mild level of dehydration can make you approximately 10% to 20% less efficient, and this makes hiking a lot less fun. The more dehydrated you become, the less efficient your body becomes at walking and cooling. Your body can only absorb about 1 quart of fluid per hour, so drink to 1 quart of some type of water or electrolyte replacement drink each and every hour that you are hiking in the heat. Carry your water bottle in your hand and drink small amounts often.

And remember if you do not balance your food intake with fluid consumption, you run the risk of becoming dangerously debilitated and severely ill. Balance your food and water intake. Eat a salty snack every time you take a drink.

Wait for the Shade


IF YOU HIKE UPHILL IN THE SUNSHINE - YOU WILL SUFFER! Even if you are eating and drinking correctly you still need to avoid hiking in direct sunlight. Sun temperatures are 15-F to 20-F (9C-11C) degrees higher than the posted shade temperatures. And remember, the lower you go the hotter it gets!

Plan your hike so you are not hiking on the trail between the hours of 10:00 am and 4:00 pm . Almost all of the people who need emergency medical help in the canyon due to heat illness were people who were hiking between 10am and 4pm. You will overheat if you hike uphill in direct sunshine. You will use up a lot of your energy trying to stay cool. You will sweat out much more water and electrolytes hiking in the sunshine, and your risk of heat-related illness will increase dramatically.

Take a break near shade and water between the hours of 10am until 4pm to avoid the worst heat of day. Enjoy a predawn start and a late afternoon finish. Always bring a lightweight flashlight to give yourself the option of hiking out after dark in the event that illness, injury, or enjoyment should slow you down. Stay Wet and Stay Cool KEEP YOURSELF SOAKING WET TO STAY COOL. This is one of the best things that you can do for yourself. Whenever you are near water, make sure that you wet (actually soak) yourself down. If you hike while soaking wet you will stay reasonably cool. This will make a wonderful difference in how well you feel, especially at the end of the day!

Featured Outdoor Gear

We escape the riff-raff of crowded campgrounds by backpacking with the light roomy Big Agnes Copper Spur HV UL2 Tent....
Price subject to change | Available through

National Park Spotlight
Bryce Canyon National Park
Bryce Canyon National Park
Featured Wildlife
Maine Puffins
Maine Puffins

Maine ocean islands provide the only nesting sites for Atlantic puffins in the United States. Eastern Egg Rock in the midcoast region, Seal Island and Matinicus Rock at the mouth of Penobscot Bay, and Machias Seal Island and Petit Manan Island off the downeast coast provide habitat for more than 4,000 puffins each summer.

Currently Viewing
Grand Canyon National Park Smart Hiking
Outdoor Gear
Featured National Parks
Popular Activities