Whiteout

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KW explains his understanding of the difference between particulate and refractive whiteout. Both are extremely disorientating conditions.

Whiteout is a state of considerable available light, but minimal visual information. It is the equivalent to being in the dark, but a torch will not help.

Particulate whiteout is a condition in which low cloud engulfs the observer, masking the horizon and all surface features of the white landscape. There is no sense of depth, form or distance.

Refractive whiteout is where there the atmosphere is perfectly clear, but sunlight is muted, diffused and refracted through white cloud onto the ice from many different directions. This reduces contrast, masks the shadows which would otherwise define its forms, and eliminates light reflection from ice and snow crystals. There is no visible horizon.

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A white subject on a white ground is illuminated with a single light source. Gradually, light from other directions accumulates, until there are no shadows. All that is visible is white light.