User blog comment:Xilinoc/Ch. 549 - The Stormbringer/@comment-823339-20130917154339

Yoruichi quite clearly has lightning-typed Shunko. Ikkaku even confused it for a lightning strike during the Soul Society arc. I assume its types have something to do with the nature of one's reiatsu, like Yamamoto's reiatsu being fire, Hitsugaya's being cold, etc.