DCHP-1 Online
white-out 
1 n. Esp. Arctic a meteorological phenomenon in which the light from a cloudy sky is balanced by that reflected off the snow on the ground, resulting in a dazzling whiteness and the neutralization of all significant features of the landscape, including shadows and the horizon.
See also: gray-out
- 1958 There is no sense of direction during a "white-out," as the compass is not effective in that part of the Arctic.
- 1965 . . . Gibson flew into a "white-out"--a condition existing in snow or haze when no horizon can be seen. . . .
2 n. North See quote.
- 1965 Even more dangerous to aviators [than grey-out] is the white-out that occurs when the whole landscape is obscured by mist or drifting snow, and visibility drops to yards, sometimes very suddenly.
- 1958 There is no sense of direction during a "white-out," as the compass is not effective in that part of the Arctic.