This leads to an inability to position yourself relative to the surroundings. are significantly reduced or completely blocked. the horizon, terrain features, slope aspect, etc. Result: Due to a reduction in reflected light, visual references e.g. The remaining scattered light is merged and blended. Cause: Sunlight is blocked, reduced and scattered by ice crystals in falling snow, wind-blown spin-drift, water droplets in low-lying clouds or localised fog, etc. Whilst there are similarities, both the causes and effects are different.Ī whiteout is a reduction and scattering of sunlight. Where ground-level thick fog exists in a snow-covered environment, especially on open areas devoid of features.Ī whiteout should not be confused with flat-light.An example of this is during lake-effect snow or mountain-effect snow, where the volume of snow can be many times greater than normal snows or blizzards. In snowfall conditions, the volume of snow falling may obscure objects reducing visibility to near zero.In blizzard conditions, snow already on the ground can become windblown, reducing visibility to near zero.There are three different forms of a whiteout: Normal snowfalls and blizzards, where snow is falling at 3 or 5 centimeters per hour (1 or 2 in/h), or where the relief visibility is not clear yet having a clear field of view for over 9 meters (30 ft), are often incorrectly called whiteouts. Motorists typically have to stop their cars where they are, as the road is impossible to see. A person traveling in a true whiteout is at significant risk of becoming completely disoriented and losing their way, even in familiar surroundings. There is no visible horizon." Ī whiteout may be due simply to extremely heavy snowfall rates as seen in lake effect conditions, or to other factors such as diffuse lighting from overcast clouds, mist or fog, or a background of snow. No surface irregularities of the snow are visible, but a dark object may be clearly seen.
Whiteout has been defined as: "A condition of diffuse light when no shadows are cast, due to a continuous white cloud layer appearing to merge with the white snow surface. The horizon disappears from view while the sky and landscape appear featureless, leaving no points of visual reference by which to navigate there is absence of shadows because the light arrives in equal measure from all possible directions. It could be also applied when visibility and contours are greatly reduced by sand.
Whiteout, white-out, or milky weather is a weather condition in which the contours and landmarks in a snow-covered zone become almost indistinguishable.
Whiteout in Saskatchewan (March 2007) Approaching whiteout in Athens (February 2021) Whiteout snow squall northwest of Waterloo, Ontario, Canada (February 27, 2014) Relatively large, stationary whiteout on Lyell Icefield that lasted 4 hours
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