Which weather condition is often a significant hazard in aviation due to low visibility?

Fog is often considered a significant hazard in aviation primarily because it can drastically reduce visibility, sometimes to a point where it becomes challenging for pilots to take off, land, or navigate safely. When visibility falls below certain thresholds, it can lead to delays, diversions, or even accidents if appropriate precautions are not taken.

In contrast, while rain and snow can also affect visibility, they typically do not create the same near-zero visibility conditions that fog can induce. Rain could produce some reduction in visibility depending on the intensity, but it is usually not as severe as fog. Snow can accumulate on runways and impact operations, but the falling snow itself often allows for better visibility compared to dense fog. Thunderstorms, while certainly dangerous for other reasons such as turbulence, lightning, and wind shear, usually do not produce the same pervasive low visibility conditions as fog. Therefore, understanding the unique characteristics of fog is crucial for assessing aviation safety in low visibility situations.