Fire Plume Ridge is the volcano subzone in the middle of Un'Goro Crater. Lava flows down the sides of the mountain, where fire elementals of lvl 51-54 can be found. A mighty fire elemental, Blazerunner, lives at its peak. During Elemental Invasions, more fire elementals and Baron Charr appear here.
The hottest place in the ridge is apparently 428,000 degrees Kraklenheit. (Krakle' Thermometer says: Holy Krakle! The temperature is 428,000 degrees Kraklenheit!)