Janūb means a southerly wind and shamʾal a northerly wind. Opposing directions suggest repeated changes in the weather. The verb's image of weaving is figurative: winds move and interlace sand and dust as threads are moved in cloth.
Traces of an old campsite may alternately be buried and exposed. This helps explain the imagery without reducing the verse to a single definite physical mechanism.
Wind becomes an active force in the scene, yet some remnants of the past still resist disappearance.