vurtual:

Vatnajökull Ice Cap, Iceland by orvaratli

“This ice cave is on the edge of the glacier where it enters into an lagoon near Svínafellsjökull. It is only possible to access it when the lagoon is frozen. 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 millimeter loud sounds could be heard.”