The neve, which generally consists of broad sheets of great beauty, is formed from the freshly fallen snow during a series of alternate thaws and frosts.
However, the dragon takes them down to the hot geysers of the Hotwater Valley where he thaws them out.
This happens in other cars, but the heat from the engine quickly thaws the plug of ice.
So maybe warming thaws the permafrost, which in turn produces more greenhouse gases, and more warming.
Heaving occurs when soil freezes, then thaws.