"Ice caves are in general unstable things and can collapse at any time. ... They are however much more stable in winter when the cold temperatures harden the ice. Even so we could hear constant cracking sounds inside the cave. It was not because it was going to collapse but because the cave was moving along with the glacier itself. Each time the glacier moved a millimetre loud sounds could be heard."
Örvar Þorgeirsson i Daily Mail om isgrottorna vid Svínafellsjökull, en utlöpare av Vatnajökullmassivet.