A gas cloud is a small pocket of floating gas that forms in certain regions; its type of gas depends on its current location. They can be seen by anyone, and anyone with a [Zapthrottle Mote Extractor] in their bags can track them on the minimap, but only engineers using the [Zapthrottle Mote Extractor] can acquire the gas within. Unlike other resource nodes, gas clouds are mobile. Sometimes a cloud will be in an inaccessible location, in which case players need to wait for it to move into range before harvesting it.

Types

When first introduced in the Burning Crusade expansion pack, each type of cloud produced one type of mote and was only found in one area. These are:

• Arcane Vortexes in Netherstorm for  [Motes of Mana]
• Felmist in Shadowmoon Valley for  [Motes of Shadow]
• Swamp Gas in Zangarmarsh and The Steamvault for  [Motes of Water]
• Windy Clouds in Nagrand for  [Motes of Air]

In the Wrath of the Lich King expansion pack, the clouds appear throughout most of Northrend and usually contain two types of crystallized elements. These are:

• Arctic Clouds in Howling Fjord, Dragonblight, Storm Peaks, and Icecrown produce  [Crystallized Air] and  [Crystallized Water].
• Cinder Clouds in the Savage Thicket in Sholazar Basin, Cauldron of Flames in Wintergrasp, and Obsidian Dragonshrine in Dragonblight produce  [Crystallized Fire].
• Steam Clouds in Sholazar Basin and around the Geyser Fields and Scalding Pools in Borean Tundra produce  [Crystallized Fire] and  [Crystallized Water].

Patch changes

Patch 3.2.0 (04-Aug-2009): [Mote Extractor] now has innate tracking for gas clouds while it is in your inventory. Tracking of gas clouds has been removed from goggles. 
Patch 2.3.0 (13-Nov-2007): Windy Clouds in Nagrand now produce  [Motes of Air]. 
Patch 2.3.0 (13-Nov-2007): Swamp Gas in Zangarmarsh now produce  [Motes of Water] instead of  [Motes of Life].