Yep, quite a common problem you have there. You just need to sacrifice two babies, a goat and bathe in their blood for the glory of satan.
All jokes aside, when did you notice this? If it was fighting an ice wraith then this might help:
"It is difficult to un-equip the ice wraith, after doing so, it will disappear, but its smoke will remain present. Something similar has also been observed to occur on PC: The head of an ice wraith will appear underneath the players feet along with its signature frosty steam effect. It's most visible when the player is walking on steep slopes or jumping, and it seems to have a habit of growing and shrinking repeatedly. A possible fix is to enter the following console command 'player.addspell 000caf8a"and then "player.removespell 000caf8a" "-http://elderscrolls....wiki/Ice_Wraith
Remember to close the console commands window after entering the first command. Keep us posted.