What characterizes katabatic winds?

Katabatic winds are characterized by their flow from high to low elevations, typically following the terrain down to valleys. This phenomenon generally occurs at night when the air near the surface cools more rapidly than the air at higher altitudes. As the cooler, denser air accumulates in the valleys, it creates a downhill flow, which is recognized as katabatic winds. This process is influenced by the cooling of the Earth's surface after sunset, leading to a stable atmosphere where the cold air descends.

The other alternatives do not accurately describe katabatic winds. For instance, winds that blow from low to high elevations contradict the very nature of katabatic flow, as these are defined by descending motions. Winds blowing during the day typically involve different mechanisms, such as thermal winds influenced by heating and convection. Additionally, winds blowing from the sea to land refer to sea breezes, which arise from temperature differences between land and water, not from high elevation flows that define katabatic winds.