Refer to figure.
When wind encounters obstacles like hills or mountains, it is forced to ascend, causing it to cool adiabatically. As this unsaturated air rises, it cools at the Dry Adiabatic Lapse Rate (DALR). If the temperature falls below the dew point, cloud formation occurs. Mountains and hills are typically efficient cloud generators, producing what are known as orographic clouds. The nature of these clouds depends on the atmospheric stability.

In unstable air, the initial uplift leads to continuous rising of the air parcel, resulting in rapidly developing cumuliform clouds (CB, TS), which are characteristic of unstable weather. Such conditions can lead to severe storms, with mountains enhancing the uplift and providing vertical support, causing severe turbulence, icing, lightning, and hail. These clouds can often be found embedded within other, less threatening cloud formations.