Took me a while to realize: The Sethrak use Sandstorm Elemental Magic! You can even see the Sand mixing with the Lightning!
To those thinking Sand is Earth Magic let me direct you to the Monk Windwalker Fists of the Heavens Artifact Questline which reveals Sand Elementals in Skywall! Sand seems to clearly be a form of East Wind Magic!
Sand is East Wind Magic and Lightning is South Wind Magic so logically Sandstorm is Southeast Wind Magic!
The only North Wind Magic we’ve seen in Elemental Form is wielded by the Lord of the North Wind, Storm Dragons and the Frost Death Knights and Lich King…
How did the Nathrezim learn about North Wind Magic to the point where the Scourge Undead are it’s most prolific users?
West Wind is healing Green Air Magic.
Shocking how Air has 6 distinct Magics(Air, Lightning/South Wind, Sand/East Wind, North Wind, West Wind and Sandstorm/Southeast Wind) in it’s capabilities with one being the result of 2 of them blending together!
Someone on Wowpedia should note the appearance of Sand Elementals in Skywall and thus list them(and Sandstorm Elementals) as an Air Elemental subtype just as the Lightning Elemental is listed!