Sandstorm elementals are a type of elemental that are primarily found in Vol'dun and who — as the name suggests — appear to embody both sand and lightning.
With the corruption of her temple, the loa Sethraliss' command of lightning has created twisted elementals, the most powerful which is Galvazzt.
In the RPG
This section contains information from the Warcraft RPG which is considered non-canon.
Sandstorm elementals are elemental conglomerates of earth, water, and air. They speak the languages of Terran, Aquan, and Auran. Rocknar may have been intended to be one.