Cloud streets . These clouds exhibit a double periodicity. Streaky clouds . These clouds have a direction without periodicity. Fog or ground hazes .
Fog usually occurs in low areas such as valleys, canyons and craters.
It forms during the coolest times of the day such as dawn and dusk. These are elongated clouds. They appear to have a source of rising material and in many case are composed of dust particles. Along the edge of the polar cap, cyclonic disturbances are common during the late summer and fall. This storm system is located at the edge of the northern polar cap.