In winter operations in the continental United States, rapid ice buildups are more likely at altitudes below 15,000 feet AGL. This altitude range is where most of the supercooled liquid water can be found. Further north, the freezing level can reach the surface, which may cut off low-altitude "escape routes".

During the winter, air masses tend to be colder and, due to the lower temperatures, more stable and contain less water vapor. These stable environments tend to produce stratus cloud formations. However, in the southern U.S., winter conditions can include cumulus clouds, much like summer conditions in the northern states.