Board Thread:Skyrim/@comment-1401879-20130526084217/@comment-6881629-20130730172430

Dukaan is the frost specialist (Ahzidal is fire and Zahkriisos is lightning) but yeah any frost spell saps stamina but also has a chance to slow movement and makes you look like your covered in a thin layer off frost. Dukaan and Malkoran do seem to be able to do it all the time high level Forsworn seem to have a high chance of it for me. They all have lots of perks for frost magic probably helps the chance they activate it.