Unless you're arriving from an area known to be suffering from an epidemic (particularly cholera or yellow fever), inoculations or vaccinations are not required for entry into the United States. During your visit to the Grand Canyon, it is helpful to keep the following in mind:
Bugs, Bites & Other Wildlife Concerns -- The Grand Canyon offers a spectacular range of flora and fauna. It's important to keep wildlife wild -- that means never approaching or feeding any animal and staying at least 300 yards away from larger animals. The National Park Service cautions that deer and elk can be aggressive and will defend their territory, and that even squirrels can bite, so don't feed them.
High-Altitude Hazards -- The Grand Canyon rim's high elevation (approximately 7,000 ft.) can lead to altitude sickness, shortness of breath, fatigue, and even nausea. Be sure to drink plenty of water and take it easy, particularly when you first arrive to this elevation. Remember when hiking that climbing back out of the canyon is far more difficult at these elevations than descending into it, so pace yourself.
Sun/Elements/Extreme Weather Exposure -- The Grand Canyon's intense sun, particularly in summer, can cause severe dehydration. Be sure to drink plenty of water, protect yourself from the sun, and avoid hiking into the canyon during the sweltering summer heat.
In 2001, two Arizona writers published a disconcertingly thick book detailing every known fatal accident within the canyon. Over the Edge: Death in Grand Canyon (Puma Press, Flagstaff, 2001) not only tells captivating stories but also serves as a handy reminder of what not to do here. (For starters, don't remove your hiking boots and run barefoot toward the river.) Below is a list of guidelines that will keep you from getting into Over the Edge: Volume II.
- Exercise caution on the rims. Every year, a handful of people fall to their deaths in the canyon. To minimize risk, don't blaze trails along the rim, where loose rocks make footing precarious. Use caution when taking photographs and when looking through your camcorder's viewfinder (unless you want your final footage aired on the nightly news). Be prepared for wind gusts, and keep an eye on your children.
- Move away from rim overlooks during thunderstorms. Get away from the rim during thunderstorms, where lightning frequently strikes and is extremely dangerous. On the rim, you may be the highest point -- and, therefore, the best lightning rod -- for miles around. Hair standing on end is a warning that an electric charge is building near you. If you hear thunder or see lighting, move as far away as possible from the rim and don't touch or cower under metal objects or tall trees. The safest place to be is inside a vehicle. If you are stuck out in the open, crouch down on the balls of your feet to minimize your contact with the ground until the lightning has passed.
- Wear sunscreen and protective clothing. Even during winter, the Arizona sun can singe unsuspecting tourists. To protect your skin and cool your body, wear long-sleeved white shirts, wide-brimmed hats, sunglasses, and high-SPF sunscreen.
- Choose a reasonable destination for day hikes. Although most park visitors quickly recognize the danger of falling into the canyon, they don't always perceive the danger of walking into it. Every year, the canyon's backcountry rangers respond to hundreds of emergency calls, most of them on the corridor trails (Bright Angel, North Kaibab, and South Kaibab). Day hikers are lured deep into the canyon by the ease of the descent, the sight of other hikers continuing downward, and, sometimes, the goal of reaching the river. As they descend into the canyon's hotter climes in late morning, temperatures climb doubly fast. By the time they turn around, it's too late. They are hot, fatigued, and literally in too deep. When hiking in the canyon, particularly during the summer months, pick a reasonable destination, and don't hesitate to turn back early.
- Don't hike midday during hot weather. Hiking when it is hotter than 100°F (38°C) will cause you to sweat out fluids faster than your body can absorb them, no matter how much you drink. For this reason, hiking in extreme heat is inherently dangerous. Think twice before you hike into the canyon during summer.
- Yield to mules -- If you encounter mules, step off the trail on the uphill side and wait for instructions from the wranglers. This protects you, the riders, and the mules.
- Drink and eat regularly when hiking -- During a full day of hiking, plan to drink more than 1 gallon of water; on the hottest days, make it more than 2. Consume both water and electrolyte-replacement drinks such as Gatorade. Also, remember that eating carbohydrate-rich, salty foods is as important as drinking. If you consume large amounts of water without food, you can quickly develop an electrolyte imbalance, which can result in unconsciousness or even death.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.