Bands of low clouds associated with a supercell severe convective storm (Cumulonimbus), arranged parallel to the low-level winds and moving into or towards the supercell.
These accessory clouds form on an inflow band into a supercell storm along the pseudo-warm front. The cloud elements move towards the updraft into the supercell, the base being at about the same height as the updraft base. Note that flumen are not attached to the murus wall cloud and the cloud base is higher than the wall cloud.
One particular type of inflow band cloud is the so-called 'Beaver's tail'. This is distinguished by a relatively broad, flat appearance suggestive of a beaver's tail.