Rising nearly 5,000 feet above Yosemite Valley and 8,800 feet above sea level, Half Dome is a Yosemite icon and a great challenge to many hikers. Despite an 1865 report declaring that it was "perfectly inaccessible, being probably the only one of the prominent points about the Yosemite which never has been, and never will be, trodden by human foot," George Anderson reached the summit in 1875, in the process laying the predecessor to today's cable route.

Today, thousands of people reach the summit. For most, it is an exciting, arduous hike; for a few, it becomes more of an adventure than they wanted. Indeed, park rangers assist hundreds of people on the Half Dome trail every summer. Most of these emergencies could have been prevented... read on to learn how.

Much of the hike to Half Dome is an adventure into Wilderness, and, while there is nothing you can do to guarantee your safety, below you will find some tips to reduce your risk and have a safer, more enjoyable hike.

Hiking

The approximately 15-mile round-trip hike to Half Dome is not for you if you're out of shape or unprepared. You will be gaining elevation (for a total of 4,800 feet) most of your way to the top of Half Dome. Most would say the reward is worth the effort. Along the way, you'll see outstanding views of Vernal and Nevada Falls, Liberty Cap, Half Dome, and--from the shoulder and summit--panoramic views of Yosemite Valley and the High Sierra.

Please be warned there is an increase in crowding and congestion on Saturdays and holiday weekends on Half Dome. Most visitors arriving at the cables during these periods will experience slow access to the summit, extended exposure to potentially uncomfortable conditions, and an increased likelihood of irresponsible behavior due to frustration with conditions. We strongly recommend planning your Half Dome visit for days other than Saturdays or holiday weekends.

Most hikers take 10 to 12 hours to hike to Half Dome and back; some take longer. If you plan on hiking during the day, it's smart to leave around sunrise (or earlier) and then have a non-negotiable turn-around time. For instance, if you haven't reached the top of Half Dome by 3:30 pm, you will turn around. Check for sunrise and sunset times before you hike. Regardless, each person should carry a flashlight or headlamp with good batteries (hikers commonly struggle down the trail after dark because they don't have a flashlight). Although the trail is well marked, you should be prepared with a good topographic map and compass and know how to use them.

Another easy way to make your hike enjoyable is to have well broken-in boots with good ankle support and good traction. Some of the most common injuries Half Dome hikers suffer are blisters and ankle injuries; good footwear is the best way to prevent these problems.

Half Dome Cables

The most famous--or infamous--part of the hike is the ascent up the cables. The two metal cables allow hikers to climb the last 400 feet to the summit without rock climbing equipment. Since 1919, only a few people have fallen and even fewer have died. However, injuries are not uncommon for those acting irresponsibly.

Tips while using the cables:

• Take your time and be patient with slower hikers
• Allow faster hikers to pass you (when possible)
• Remain on the inside of the cables
• Do not attempt the ascent if:
  • Storm clouds are in the area
  • The ground is wet (the cables and rock become very slick when wet; most accidents on the cables occur during wet conditions)
  • The cables are down for the winter (approximately early October to late May) (check conditions update for status)

Cutting Switchbacks

While hiking anywhere in Yosemite, do not take shortcuts off the trail or across switchbacks; this causes trail erosion and is illegal.

Gloves and Trash

Many people find gloves helpful on the cables. However, if you bring your gloves up, pack them out. Hundreds of pounds of rotting gloves otherwise accummulate.

There is no trash service on trails. While hiking in Yosemite, be sure to pack out all trash. When possible, you can help park rangers by picking up trash that you encounter on the trail. Bearproof trash cans are available at trailheads.

Wildlife

Black bears frequent Yosemite's Wilderness and are adept at grabbing backpacks from hikers and campers--during both day and night. Always keep your food within arm's reach (or on your back); never leave it unattended. If you see a bear, act immediately to scare it away: make as much noise as possible by yelling. If there is more than one person, stand together to present a more intimidating figure, but do not surround the bear.

Squirrels, Stellars jays, chipmunks, and other animals also live along the trail; never feed them or allow them to get your food. Do not leave your pack unattended (e.g., at the base of the cables or while you take a swim or nap). Keep wildlife wild: respect them from a distance.

Improper food storage and feeding of wildlife may result in a fine (up to $5,000).

Environmental Illness and Injury

The summit of Half Dome is a dangerous place during a lightning storm. Check the weather forecast before your hike and try to reach the summit early in the day to avoid afternoon thunderstorms. If a storm appears nearby, do not continue to the summit and, if in the summit area, leave the area (while still using caution when descending the cables and steps).

The summit is typically 15°F (8°C) to 20°F (11°C) cooler than Yosemite Valley and windy conditions are common. Be prepared for cool temperatures and rain showers.

A few visitors each summer have problems with altitude sickness. Symptoms may include severe headache and/or nausea. The only way to relieve altitude sickness is to descend immediately. Other environmental illnesses include heat exhaustion, dehydration, and hyponatremia (low electrolyte levels). In addition to drinking plenty of water, be sure to eat, and to take regular rest breaks in the shade.

Water

One of the easiest ways to ensure a safe, enjoyable hike is to be sure to have plenty of water. Weather conditions and personal preference affect the amount of water you need, but suggested minimum amounts per person are:

• 1 gallon (4 liters) if hiking to the top of Half Dome
• 2 quarts (2 liters) if hiking only to the top of Nevada Fall
• 1 quart (1 liter) if hiking only to the top of Vernal Fall

The only treated water on the trail is available (summer only) at a drinking fountain at the Vernal Fall Footbridge (less than a mile from the trailhead). Merced River water is available up to Little Yosemite Valley, however you should treat this water by boiling, using iodine, or using a giardia-rated water filter. Drinking untreated river water may cause significant illness.

Restrooms

Flush toilets are available at the Vernal Fall Footbridge (below Vernal Fall). Composting toilets are available near Emerald Pool (above Vernal Fall), near the top of Nevada Fall, and in Little Yosemite Valley.

At any other location, you are required to bury any solid human waste at least six inches (15 cm) deep and at least 100 feet (30 m) from water or trails. Pack out toilet paper.

Emerald Pool

Entering Emerald Pool, the Silver Apron, and the pools above Nevada Fall are strongly discouraged because of frequent injuries and fatalities.

Emergencies

Even if you plan properly and bring the correct equipment, you might still encounter problems. Some cell phones have coverage from Half Dome and from some locations on the trail. Little Yosemite Valley Ranger Station is staffed during summer. You can find the ranger station on the north side of the valley, near where the Half Dome Trail begins to climb out of the valley. Park rangers frequently patrol the trail, so the ranger station is not always staffed. You may need to send some members of your group to Yosemite Valley to get assistance.