South Ice Cave

South Ice Cave is in Lava Beds National Monument in northern California, USA. It is a lava tube known for perennial ice formations beneath the surface.

Cold air becomes trapped in the underground lava tube, while the cave's structure limits mixing with warmer outside air. This allows ice to persist even during California's warmer months.

It is a lava tube, formed when the surface of a lava flow cooled while molten lava continued moving beneath it. The remaining tunnel later became a cave with a cold-trapping microclimate.

South Ice Cave is part of the cave system at Lava Beds National Monument, where conditions can be dark, uneven, and cold. Visitors should check current park access rules and carry suitable lighting and footwear before entering.