Mountain Hazards

Mountain Hazards:

“Safety” and “Hazard” are interrelated terms and therefore it is of utmost importance to analyse the hazards prevalent in the mountains to ensure the safe conduct of an expedition or trek.

Mountain hazards can mainly be categorised in two broad classifications – Natural and Manmade.

Natural Hazards are the ones in which humans have no control whereas Manmade Hazards are the ones which can be avoided with proper planning and preparation.

Natural Hazards (Objective Hazards):

River in Spate

This is the sudden increase in water levels of a river or stream resulting from melting of snow or sudden heavy rain fall. At high altitude, as the day progresses, glacial streams and rivers experience rise in water levels due to rise in temperature at their source. Campsites should be at a safe distance from the river/stream course and crossing of streams and rivers are preferable before afternoon when the water levels are low.


Avalanche is a mass of unstable snow or ice descending down a mountain slope destroying everything in its path. An avalanche is triggered by overloading of snow on slope, shearing and bonding of snow molecules, and vibration resulting from sound, skiing, earthquakes and blast.

Avalanche zones should be avoided by negotiating the safest route and appropriate slope. In avalanche prone areas, one shouldn’t walk in a zig-zag manner on the snow slope, ensure to maintain silence and not stamp feet into the snow. A person should always be kept on watch while crossing avalanche prone areas. Venturing onto a slope after heavy snowfall should be avoided. It is important not to rope up in avalanche prone areas, unbuckle the rucksack waist strap to avoid getting trapped in the avalanche with the load, and to maintain proper distance between climbers.


Landslide is downslope movement of rock, soil, debris due to failure of materials holding the hill slope. Landslides are caused by purely natural causes (earthquake) or a combination of natural causes and human activity like deforestation, mining, construction, combined with heavy rainfall. Wet slopes without vegetation should be avoided as they are more prone to landslide. In general, landslide prone areas should be avoided during heavy rains.


This is a deep crack in a glacier, formed due to the stress produced by the movement of the glacier. Crevasses can be open or hidden below snow. It is advisable to rope up while crossing a glacier and keep adequate distance between two successive climbers. In case of hidden crevasses, it is expected that probing on the route should be carried out before proceeding ahead.

Rock Fall

The frequent change in temperatures at high altitudes leads to a cycle of freezing and thawing of ice. These result in formation of cracks in the rocks, eventually leading to rock chunks breaking away and falling off. Rock fall can also occur due to melting of snow/ice holding the rock in place. This is a common hazard in the mountains that can lead to injury or even fatality. In a rock-fall area, one should stay vigilant, and if cautioned of rock fall, look up and try to find the falling rock. On locating the falling rock, look down and press flat against the cliff face. Helmets should be worn to minimise the injury.


  • Lightning
    Lightning is a frequent hazard on mountains. In the event of lightning, open expanses of snow and glaciers are potentially safer than rocky areas. In case of lightning, everything which can act as a strike point and comes in the path of electricity conduction should be avoided, such as gullies, crevices and cracks, chimneys, caves or large isolated rocks and trees. Maintain distance from peaks, metallic equipment (crampon, ice axe, etc.). It is advisable to sit away from sheer rock faces with feet together, knees bent up and held against the body.
  • White Out
    White Out is a condition of low visibility and contrast leading to disappearance of horizon and reference markers due to blizzard, heavy snowfall, cloud descending onto the hills or thick fog in a snow heavy environment. This can lead to disorientation and walking off the edge of a mountain side. It is advisable to rope up in such conditions.
  • Snow on Trees
    Hard snow accumulated on trees over a period of time is a falling object hazard. Accordingly, camping and resting below trees with snow accumulated on them should be avoided.
  • Blizzard
    These are snowstorms with high wind velocities (typically greater than 56 kmph) lasting for prolonged period of time. A ground blizzard has high velocity winds blowing loose snow off the ground. Blizzards cause reduced visibility due to White Out and can also cause avalanches in the mountains.

Seracs and Hanging Glacier

These are towers of ice that can fall anytime due to the movement of the glacier, without warning. If unavoidable, they should be crossed quickly while maintaining proper distance between two successive climbers. Wearing a helmet while crossing the icefall zones is advisable.


The universal classification of altitude is as follows:

  • High altitude – 8000 to 12000 feet
  • Very high altitude – 12000 to 18000 feet
  • Extremely high altitude – More than 18000 feet

Due to oxygen deficiency at high altitudes, the human body undergoes physiological changes which includes breathlessness on exertion (hyperventilation), increased urination, sleep disturbance, gastric flatulence, increase in blood viscosity (hypercoagulability), and loss of appetite and weight.

Slow ascent, taking proper rest, drinking enough water, eating carbohydrates, avoiding alcohol and smoking, climbing at a comfortable pace, and climbing high and sleeping at lower altitudes are some of the common means that help in acclimatisation. Improper acclimatisation at high altitude can lead to mild symptoms of Acute Mountain Sickness (AMS), which can aggravate to the potentially fatal High-altitude Pulmonary Oedema (HAPO) and High-altitude Cerebral Oedema (HACO).

Snow Cornices

Snow cornices are formed due to the deposition of snow over sharp terrain breaks such as ridges, along the side of gullies and the steeper side of mountains by winds. Cornices are most commonly formed on the leeward side of mountains. In a cornice, the snow builds out horizontally and is extremely susceptible to collapse and triggering avalanches. Traveling above or below the cornice is dangerous and should be avoided.

Manmade Hazards (Subjective Hazards):

Slip and Fall

This is a human hazard caused mainly due to poor decision making, inadequate fitness, over fatigue, climbing beyond one’s ability (inadequate skills), dehydration, poor maintenance of ropes leading to breaking or the ropes getting cut against sharp edges.

Manually Triggered Rock Fall

While climbing along rocky sections, the probability of stepping on and dislodging a rock is very high and this can be potentially dangerous for other climbers following behind. Caution has to be taken to ensure that foot steps are carefully placed and all climbers should be on the lookout for falling rocks while maintaining adequate distance between each other.

Acute Mountain Sickness (AMS)

AMS happens due to poor acclimatisation at high altitudes. It is more common for AMS to happen in between the first 12 to 24 hours of arrival at altitudes above 9000 feet due to blood dilation. The most common symptoms are headache, nausea, dizziness, fatigue, loss of appetite, and sleep disturbance. AMS must not be taken lightly as it can lead to HAPO or HACO. If no improvement is noticed or the condition worsens, it is advisable to stop further ascent and descend to lower altitudes immediately.

High-altitude Pulmonary Oedema (HAPO)

HAPO is a life threatening medical condition in which fluid accumulates in the lungs. At high altitudes, the entire lung is starved of oxygen, leading to constriction of the blood vessels that receive oxygen from the lungs. The blood in these vessels is squeezed, thereby increasing the pressure. This causes fluid to be forced out of the blood into the air pockets and subsequently accumulating in the lungs.

Symptoms of HAPO are breathlessness at rest, dry or productive cough, chest pain, fever and weakness, or decreased exercise performance. HAPO requires urgent descent to lower altitudes with hyperbaric oxygen treatment.

High-altitude Cerebral Oedema (HACO)

HACO is the least common but potentially the most fatal form of AMS. HACO occurs when the body is exposed to low oxygen environment before proper acclimatisation, causing oxygen deprivation or hypoxia. Usually HACO is preceded by AMS. Long exertion in low oxygen causes low carbon dioxide in the blood cells which also aids in HACO. In this medical condition, the fluid accumulates inside the brain, causing the brain to swell.
Symptoms of HACO are disorientation, lethargy, hallucination, confusion and altered consciousness or coma. HACO is fatal and one can get killed within a few hours. HACO can only be cured through rapid descent to lower altitudes accompanied by hyperbaric treatment and supplemental oxygen.

Cold Injuries

  • Chilblain
    This is the first sign of a cold injury, caused due to the exposure of bare skin areas like earlobes, nose, toes, finger, cheeks, hands and feet to the cold and humid air. The symptoms are swollen and red skin, tenderness and itching. Chilblain can be avoided by covering the exposed areas by gloves, socks, balaclava or scarf. Layers of socks should be used if the feet are cold, and toes and fingers should be moved all the time to allow for proper blood circulation. The areas affected by chilblain need to be kept dry and warm.
  • Frostbite
    Frostbite is the freezing of tissue on exposure to temperatures below 0°C due to high wind velocities, and also by wearing damp socks and gloves. It is considered as a medical emergency in snow bound areas and proper prevention should be taken to avoid frostbite by keeping hands and feet dry and warm using multiple layers of clothing, socks, waterproof shoes, trousers and jackets to retain body heat. To allow for proper blood circulation, hands and feet should be kept active at all times.
  • Immersion Foot/ Trench Foot
    This is a medical condition caused due to the prolonged exposure of feet to wet conditions, and inactivity in damp socks and boots. The symptoms are cold and numb foot, shooting pain, swelling and redness. This condition can be avoided by changing damp socks, using protective clothing in many layers, avoiding prolonged immobilisation and application of Vaseline.
  • Hypothermia
    This is the loss of body temperature that can cause potential threat to life. Hypothermia can be accidental, where the whole body is exposed to extreme cold due to avalanche, falling into a crevasse, heavy snowfall, or by immersion where the whole body remains in contact with cold water for a prolonged duration of time. The symptoms can be mild (shivering), moderate (violent shivering, slurred speech, irrational behaviour – paradoxical undressing, loss of fine motor coordination, altered sensorium) or severe (shivering in waves, muscle rigidity, dilated pupils, falling on ground and curling up into foetal position to conserve heat, and metabolic icebox where the victim looks dead but is still alive).
    This is a medical emergency and the victim should be kept warm, dry and moving. The victim can be rewarmed using electric blankets, warmed air, hot water bath and sleeping bags. If the victim is unconscious, it is essential to maintain the body in a posture where the airway isn’t restricted, breathing and circulation is unobstructed, and ventilation is provided with warm and humid oxygen.
  • Metal Bite
    In sub-zero temperatures, if a metal objects comes in contact with the skin, the moisture on the skin freezes on the metal surface, thus causing the top layer of the skin to stick on the metal surface. This can lead to the top layer of skin peeling off. To prevent this, gloves should be worn while handling metallic objects and it should be ensured that equipment like ice-axe etc. have a rubber grip. In case the skin is already stuck to a metal object, lukewarm water should be poured on the metal and skin to gently get the skin off the metal object.


This is burning from overexposure to Ultraviolet (UV) rays of sun, affecting living tissues. This can be prevented by applying sunscreen and reapplying it at frequent intervals, and by covering up the face and other exposed areas using buffs and other appropriate clothing items. Drinking lots of water helps in keeping the body hydrated, which aids in recovery from sunburns.

Snow Blindness

Snow blindness is the result of excessive exposure of surface of eye (cornea and conjunctiva) to the sun’s UV rays, leading to sunburn in the underlying tissues of the eye. At high altitudes, the sun’s UV rays are much stronger and the snow reflects 80 percent of the UV rays falling upon it. The combination of these two factors pose greater chances of snow blindness. Snow blindness can even occur during overcast conditions as clouds offer no protection from the UV rays.

The symptoms of snow blindness are temporary loss of vision, irritation and dryness in eyes, swelling, redness, excessive tearing, painful movement of eyes, pain in eyes on exposure to light, headache, and ulceration of cornea in extreme cases.

To prevent snow blindness, sunglasses with Category-4 lenses are recommended. These provide high level of protection from visible and UV rays, allowing less than 10% of the rays to transmit through the lens.

This site uses Akismet to reduce spam. Learn how your comment data is processed.