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Whiteout (weather)

earth science Maturity 7-9 Next article →

A whiteout is a severe weather condition that reduces visibility and contrast. This happens when snow, fog, or sand fills the air. During a true whiteout, the horizon disappears from view. The sky and the landscape look exactly the same. This creates a featureless world with no visual landmarks. Without these points of reference, it is impossible to navigate.

Even in familiar surroundings, a person can become completely disoriented.

There are three distinct forms of a whiteout. The first occurs during blizzard conditions. In this case, strong winds blow snow that is already on the ground. This windblown snow reduces visibility to near zero. The second type happens during heavy snowfall. This is often seen in lake-effect or mountain-effect snow. In these events, the volume of falling snow is much higher than normal. This volume obscures all objects in sight.

Whiteout to clear, Mt. Lyell and its icefield
Whiteout to clear, Mt. Lyell and its icefield

The third type involves thick, ground-level fog. This is common in open, snow-covered areas that lack natural features.

The mechanism of a whiteout involves the scattering of sunlight. Tiny ice crystals in falling snow block the sun. Windblown spin-drift or water droplets in low-lying clouds also play a role. These particles cause the sunlight to be reduced and scattered. The remaining scattered light is then merged and blended together. This reduction in reflected light removes visual references like the terrain or the horizon.

Pole line (413157823)
Pole line (413157823)

In severe conditions, this can lead to a loss of kinesthesia. This is the ability to discern your own position and movement. It can also cause confusion and a loss of balance.

It is important to distinguish a whiteout from flat-light. While they are similar, their causes and effects are different. Flat-light is caused by a diffusion of sunlight. Atmospheric particles like water molecules or ice crystals scatter the light. Snow on the ground also helps diffuse the light. This causes light to arrive from many different directions at once. This effect often increases when the sun is low on the horizon.

White-out hg
White-out hg

This happens because the sunlight must pass through more of the atmosphere.

The result of flat-light is a very specific visual change. Because light comes from many directions, shadows overlap. These overlapping shadows cancel each other out. This makes the area look dull and removes contrast. It becomes difficult to see the tones or edges of similar colored features. This can cause a loss of depth of field. This loss of depth can lead to disorientation for the observer.

White-out hg
White-out hg

Unlike a whiteout, which blocks the horizon, flat-light creates a featureless vista.

Whiteout conditions pose serious hazards to many different groups. Mountain climbers and skiers must be very careful. Aviation is also at risk during these events. On the ground, motorists face significant dangers. On large, high-speed routes, drivers often have to stop their cars completely. This is because the road becomes impossible to see. This can lead to major multiple-vehicle collisions. This happens if a forward driver stops but the driver behind cannot see the danger.

Whiteouts can even be created artificially by aircraft. Near airports or helipads, helicopter operations can stir up snow. This is caused by the rotor down-wash from the blades. Airplane jet blast can also blow snow off the ground. These man-made whiteouts are hazards to both aircraft and bystanders. History shows the danger of these conditions. In 1979, an accident occurred on Mount Erebus in Antarctica. This air accident was caused in part by whiteout conditions.

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🖼️ Images & Media (5)
File:Pole line (413157823).jpg
Pole line (413157823).jpg
Whiteout Canada.ogv
File:Whiteout to clear, Mt. Lyell and its icefield.jpg
Whiteout to clear, Mt. Lyell and its icefield.jpg
File:White-out hg.jpg
White-out hg.jpg
File:Royal Navy Commando Helicopter Force (846NAS) Merlin Mk.3 at RNoAF Bardufoss, Norway (45158529).jpg
Royal Navy Commando Helicopter Force...
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