First off, there is a typo on the Passive in the skill tree. It reads ‘Tyhoon’ rather than ‘Typhoon’
2nd, this passive doesn’t seem to work when wind tempest is proc’d while transformed using the Druid’s Call passive.
EDIT: I have confirmed it does proc tornado in human form, but I have now found that the Tornado casts via the passive does NOT apply the Aspect of the Storm buff from the Tornado tree. This is also true of Tornados cast via the Rule of the Simoon gloves.
EDIT2: Okay even casting Tornado directly doesn’t give the aspect of the storm buff.