Wherever you’re walking in desert areas, particularly between April and October, keep a lookout for rattlesnakes. You’re likely not to have any problems if you maintain distance from snakes that you see—they can strike only half of their length, so a 6-foot clearance should allow you to remain unharmed, especially if you don’t provoke them. If you’re bitten by a rattler, don’t panic. Get to a hospital within two to three hours of the bite. Try to keep the area that has been bitten below heart level, and stay calm, as increased heart rate can spread venom more quickly. Keep in mind that 30% to 40% of bites are dry bites, where the snake uses no venom (still, get thee to a hospital). Avoid night hikes without rangers, when snakes are on the prowl and less visible.
Scorpions and Gila monsters are no less of a concern, though they strike only when provoked. To avoid scorpion encounters, look before touching: never place your hands where you can’t see, such as under rocks and in holes. Likewise, if you move a rock to sit down, make sure that scorpions haven’t been exposed. Campers should shake out shoes in the morning, since scorpions like warm, moist places. If you’re bitten, see a ranger about symptoms that may develop. Chances are good that you won’t need to go to a hospital. Children are a different case, however: scorpion stings can be fatal for them. Always try to keep an eye on what they may be getting their hands into to avoid the scorpion’s sting.
Gila monsters are relatively rare and bites are even rarer, but bear in mind that the reptiles are most active between April and June. Should a member of your party be bitten, it’s most important to release the Gila monster’s jaws as soon as possible to minimize the amount of venom released. This can usually be achieved with a stick, an open flame, or immersion of the animal in water.
This underestimated danger can be serious, especially considering that one of the first major symptoms is the inability to swallow. It may be the easiest hazard to avoid, however; simply drink every 10–15 minutes, up to a gallon of water per day when outside in summer, and keep well hydrated other times of year, too, as even cool winter days can be very dry.
Temperatures in Arizona can vary widely from day to night—as much as 40ºF. Be sure to bring enough warm clothing for hiking and camping, along with wet-weather gear. It’s always a good idea to pack an extra set of clothes in a large, waterproof plastic bag that would stay dry in any situation. Exposure to the degree that body temperature dips below 95ºF produces the following symptoms: chills, tiredness, then uncontrollable shivering and irrational behavior, with the victim not always recognizing that he or she is cold. If someone in your party is suffering from any of these symptoms, wrap him or her in blankets and/or a warm sleeping bag immediately and try to keep him or her awake. The fastest way to raise body temperature is through skin-to-skin contact in a sleeping bag. Drinking warm liquids also helps.
Wear a hat and sunglasses and put on sunblock to protect against the burning Arizona sun. Try to minimize your sun exposure during the peak hours of noon to 4 pm, and watch out for heatstroke. Symptoms include headache, dizziness, and fatigue, which can turn into convulsions and unconsciousness and can lead to death. If someone in your party develops any of these conditions, have one person seek emergency help while others move the victim into the shade and wrap him or her in wet clothing (is a stream nearby?) to cool down.