What risk does an aircraft face when flying in the vicinity of a squall line?

When flying in the vicinity of a squall line, an aircraft faces severe turbulence and wind shear, which is the correct response. A squall line is a line of thunderstorms that can produce intense weather phenomena, including rapidly changing wind speeds and directions. This abrupt change, known as wind shear, can result in significant challenges for pilots, as it increases the likelihood of losing control over the aircraft or experiencing abrupt altitude changes.

The turbulence associated with a squall line can be particularly violent, leading to potentially dangerous flying conditions. Pilots must be aware of these risks and often need to navigate around such weather to ensure safety. In contrast, the other options do not accurately depict the conditions associated with squall lines. Low visibility can occur in some weather scenarios, but it is not a primary risk associated with squall lines. Similarly, stable weather conditions are not characteristic of squall lines, which are defined by their violent and unstable weather. The accumulation of ice on wings is also not directly linked to squall lines, as icing conditions depend more on temperature and moisture rather than the dynamics of a squall line itself.