University of Hawaii

Information Bulletin 31

Mauna Kea Hazards

Please read before traveling above Hale Pohaku.

Altitude Hazards

Altitude Sickness

At the summit elevation of 13,796 feet (4,200 m), the atmospheric pressure is 40 percent less than at sea level. Less oxygen is available to the lungs, and acute mountain sickness is common. Symptoms include headaches, drowsiness, nausea, shortness of breath, and poor judgment. The intensity of these symptoms may be lessened by spending at least a half hour at the Visitor Information Station (altitude 9,200 feet or 3,000 m) before traveling to the summit. If symptoms of mountain sickness persist or become severe, descend to a lower altitude immediately.

High altitude exposure is particularly hazardous for people in poor physical condition, for those with heart or respiratory problems, for pregnant women and their unborn children, and for children and teenagers under 16. It is strongly recommended that people in these categories not travel above the Visitor Information Station. Extended exposure to high altitude can cause permanent damage to young people whose bodies are still developing.

Children under the age of 16, pregnant women, people in poor physical condition, and those with heart or respiratory problems should not travel above the Visitor Information Station.

High altitudes can also cause the life-threatening conditions pulmonary edema (fluid in the lungs) and cerebral edema (fluid on the brain). Symptoms include severe headaches, vomiting, breathing difficulties, coughing, blue lips or fingernails, disorientation, and extreme drowsiness that may lead to coma. Descend immediately if any of these symptoms appears.

People experiencing any severe symptoms must be taken to lower altitudes immediately. It can be a matter of life or death.

Sunburn and Eye Damage

The summit is above much of the atmosphere that blocks the sun's ultraviolet radiation. This presents a risk of serious sunburn and eye damage, particularly when there is snow on the ground.

Use sunscreen, sunglasses, and protective clothing.

Impaired Judgment

High altitude causes impaired reasoning and drowsiness. Alcohol will further impair judgment and driving abilities.

Do not drink alcoholic beverages on Mauna Kea.

Driving Hazards

The summit access road is approximately 10 miles long and has an altitude change of nearly 5,000 feet (1,510 m). There are many sections with a grade of 15 percent. The steep grades can result in brake overheating while driving downhill. Driving slowly, and in low gear, will reduce the chances of brake failure.

Always use low gear.
Four-wheel-drive vehicles are strongly recommended.

The first five miles of road are unpaved, have poor traction, narrow sections, blind curves, and rocks on the road. In some places, there may not be enough room for two-way traffic, especially when large trucks are involved. Slow speeds are essential to avoid road hazards.

Drive at 25 miles per hour (40 km/hr) or less.

Weather Hazards

Weather on Mauna Kea can be severe and may include winds over 100 miles per hour, freezing temperatures, and snow storms. "White outs" caused by blowing snow can reduce visibility to zero. Deep snow drifts, freezing fog, and ice on the road can prevent passage. In the winter, ice may form suddenly, without warning. The steep paved grades are dangerous with just a thin coat of ice or snow. Visitors trapped on the mountain under these circumstances are in a life-threatening situation--they are in danger of freezing to death. Extreme weather that prevents the rescue of trapped visitors can last for more than a week.

Take cold weather clothing with you.
Evacuate as soon as hazardous weather begins.
Evacuate if road ice begins to form.

Remote Location

Mauna Kea is a very remote location. It has no public accommodations, food, or gasoline service. The observatory buildings are usually closed to the public. There are no permanent restrooms above the Visitor Information Station. The only public telephone above Hale Pohaku is an emergency phone in the entrance to the University of Hawaii 2.2-m Telescope building. Vehicles should be in good working condition with good brakes and sufficient fuel to return to Hilo or Waimea. Emergency services, including medical assistance, may be two hours away. Safety precautions must be taken to prevent serious injuries.

Be prepared. Use caution. Travel at your own risk.

Prepared by the Institute for Astronomy, University of Hawaii

For more information or additional copies, write to the
Assistant to the Director
UH Institute for Astronomy
2680 Woodlawn Drive
Honolulu, HI 96822

Acknowledgments: Louise H. Good, Wendy F. Nakano, and Karen M. Rehbock.

© 1995 University of Hawaii Institute for Astronomy
Latest revision August 1995

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