Stratified fluids that appear to be stable, meaning a heavier layer of fluid is located under an upper layer of less dense fluid, can be overturned if there is a heat flux into the system. In engineering literature, this type of overturn is called a “rollover” (Rice, 2000). In volcanic environments, rollover has been proposed to happen in volcanic lakes (Lake Nyos), and also in magma chambers.

 The triggers of rollover are not as well understood as the process itself, and in volcanic environments there is much speculation.

 More specific to the volcanic lake setting, rollover is thought to occur when a gradual accumulation of CO₂ through the lake bottom results in the saturation of the hypolimnion (The layer of water in a thermally stratified lake that lies below the thermocline). If heat is added to the hypolimnion, the water can be lifted and the total ambient pressure can decrease causing oversaturation and bubble formation. The exsolution of stored volatiles allows for an increase in buoyancy and turbulence within the fluid and breaks down the models of water column stability (Kanari, 1989; Kling, 1989).

(Holloway, 2000; Rice, 2000)