Arctic Phenomena

Arctic Blizzard:

An arctic blizzard is storm of intensely cold wind, laden with fine, blinding snow picked up from the ground. It is associated with arctic cold waves during which the intense cold may cause snow to break up into ice crystals or appear as a cloud of ice needles. Blizzard conditions include visibility of less than one kilometer in snow with winds equal or greater than 40 kmh that last six hours or more.

Ice Fog/ Mirages:

Ice fog is composed of suspended particles of ice. These are usually formed by freezing of water vapor which usually occurs at temperatures lower than minus 30º C. Ice fog can close airports and make travel on foot difficult.

Halos and Parhelia:

Ice crystals in the atmosphere are responsible for the appearance of halos around the sun and moon, and for "sundogs" or Parhelia. Cirrostratus clouds, containing the necessary ice crystals, float lower in polar regions reflecting light from the sun or moon. The denser the cloud, the more ice crystals, and the brighter the halo. Halos at their brightest may show a spectrum from red inside to blue outside. "Sundogs" or mock suns usually are seen in the spring. As many as eight bright spots of light may appear to radiate from the sun.

White-out:

White-out occurs during conditions of diffuse, shadow-less illumination, such as a heavy overcast, on a uniformly white surface such as the snowy arctic landscape. The effect is loss of depth perception. Landing, take-off, taxiing and low flying are hazardous under this condition. It also is difficult to operate surface vehicles safely during a whiteout. Fog, precipitation or blowing snow may reduce visibility at the same time as depth perception.