Maunakea Hazards

Printable English "Hazards" Flyer (2 page): Maunakea Hazards
Printable Chinese "Hazards" Flyer (2 pages):  Maunakea健康警告
Printable Japanese "Hazards" Flyer (2 pages):  マウナケアでの安全・健康に関する情報

Exposure to Altitude

The summit elevation is 13,796 feet (4,205m). The oxygen level in the body is greatly reduced at this altitude and visitors can experience shortness of breath, impaired judgment, and other symptoms.  Reduced atmospheric pressure at high altitudes may cause altitude sickness or result in the development of other life-threatening conditions such as pulmonary edema (fluid in the lungs) and cerebral edema (fluid on the brain).  Also, because the summit is above much of the atmosphere that blocks the sun's damaging ultraviolet rays, there is high risk of serious sunburn and eye damage, especially if there is snow on the ground.

Precautions Before Ascending the Summit

  • Prior to ascending the summit, acclimatize by spending at least 1/2 hour at the Visitor Information Station located at the 9,200 ft (2,804 m) elevation. This may lessen the intensity or onset of altitude sickness.  If symptoms occur at this elevation, do not travel above the Visitor Information Station.
  • Apply sunscreen and wear sunglasses and protective clothing.
  • Hikers should register at the Visitor Information Station, have appropriate gear (including at least 3 liters of water per person), take a map, be aware of the weather forecast, and use the buddy system.

Persons at Risk

We strongly advise the following individuals not to travel above the Visitor Information Station:

  • Pregnant Women
  • People with heart or respiratory problems
  • People in poor physical condition
  • Children under the age of 13*

* Extended exposure to high altitudes can cause permanent damage to children whose bodies are still developing.

Symptoms of ALTITUDE SICKNESS include:

  • Headaches
  • Drowsiness
  • Nausea
  • Altered mental state
  • Loss of balance
  • Impaired reason


  • Severe headaches
  • Vomiting
  • Breathing difficulties
  • Coughing
  • Blue lips or fingernails
  • Disorientation
  • Extreme drowsiness (could result in a coma)

Click to read an article about long-term brain damage from High Altitude Cerebral Edema.

If symptoms persist or become severe, immediately descend to a lower elevation.
It could be a matter of life or death!

Snow Recreation

Because some of the slopes are very steep with rocky outcroppings at the bottom, you are strongly advised NOT TO USE inner tubes, boogie boards, or other devices that are NOT equipped with braking mechanisms or which do NOT provide directional control on snow or ice.

Due to the fragile environment and cultural significance of Maunakea AND safety to you and others using the mountain, SNOW MOBILES OR ANY TYPE OF OFF-ROAD VEHICLES ARE PROHIBITED.

There is no equipment or infrasructure available for organized snow play on Maunakea
All snow recreation is at the risk of the individual

Falling Ice

During the winter ice regularly forms on the observatory buildings and other structures.  As these ice formations melt, large fragments fall to the ground without warning.  You could be injured or your vehicle could be damaged.

Do not approach observatory buildings and other structures when ice is present


Weather can change very rapidly, resulting in severe conditions including freezing temperatures, snow storms, and high winds which can reach over 100 mph.  "White-outs" caused by blowing snow and fog block all visibility.  Road conditions can become hazardous due to deep snow drifts, freezing fog, and ice preventing vehicular passage.  Visitors on the summit when severe weather occurs face a life-threatening situation.  Severe weather conditions can last up to a week preventing immediate rescue.  Should you get stuck in a severe winter storm, always stay with your vehicle.

Visitor Advisory
  • Equip yourself with cold weather clothing
  • Evacuate as soon as hazardous weather conditions begin to occur


The summit access road is approximately eight miles long and includes steep inclines.  The first five miles of the road are unpaved, with 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 on the road.  Road clearing and maintenance equipment should be given the right of way.  Stopping distances are greatly increased when there is snow or ice on the road.  Drivers should expect to see a lot of vehicles and pedestrians on the road.  Drivers should also be careful of the sun in their eyes during early morning and late afternoon.

Visitors are advised that only TRUE 4-wheel drive vehicles with LOW range travel are allowed beyond the VIS. Before proceeding visitors should consult their rental vehicle company or review their contract concerning visiting the summit of Maunakea.  Many rental companies do not allow their vehicles to continue on the the summit even if they are 4-wheel drive.
Drivers are cautioned to:
  • Use 4-wheel drive vehicles with LOW RANGE 
  • Drive slowly (Note the speed limit is 25mph)
  • Always use 4-wheel drive LOW RANGE (to reduce brake failure and overheating)
If your vehicle becomes disabled, immediately inform the Maunakea Rangers at (808) 961-2180.  You will be required to make arrangements for immediate removal or repair.  If the vehicle is a hazard to drivers and repair or towing arrangements are not immediately arranged, it will be towed at your (or the rental company's) expense.  Keep the Maunakea Rangers informed.


Remote Location

Maunakea is a very remote location.  There are no public accommodations, food or gasoline services. Observatory buildings are not open to the public.  There are few restroom facilities above the Visitor Information Station.  The only public telephone above the Visitor Information Station is an emergency phone in the entrance to the University of Hawai‘i 88-inch Telescope.  Cellular phone coverage is unreliable on the Saddle Road, Maunakea Access Road and on the summit.  Vehicles should be in good working condition, especially the brakes, and should contain sufficient fuel to return to Hilo or Waimea.  Emergency services, including medical assistance, may be two hours away.



Emergencies: 911
Visitor Information Station: 934-4550
Winter Conditions: 935-6268 (recording)

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