Tribe of Thunder
From Diablo Wiki
Of the Barbarian people, the Tribe of Thunder was the first to draw upon the primal forces of the weather. Tornadoes would ravage their plains as summer turned to the harvest season. The shaman of the tribe would interpret the tornadoes as an omen of evil during times of peace, and as a harbinger of great victory during wartime. Observing the strength of the whirlwind, these Barbarians learned to emulate the swirling mיlange of the cyclone in their attacks. As time went on and the tribes intermingled, the ability to attack in the manner of the whirlwind was passed down to all of the Barbarian people.