The correct answer is B) Lack of ability to estimate distance. During a period of "whiteout" conditions, when visibility is severely reduced due to heavy snowfall or blowing snow, it becomes extremely difficult to accurately judge distances. The lack of visual cues and contrast makes it challenging to perceive depth and spatial relationships, leading to a decreased ability to estimate distances accurately. The other options are incorrect because: A) Snowfall or blowing snow is the cause of whiteout conditions, not the expected outcome. C) Hazy horizons and mirage effects are more associated with other weather phenomena, not necessarily whiteout. D) The harsh contrast between sun-illuminated snow and the background is a common characteristic of whiteout conditions, but it does not directly impact the ability to estimate distance.