Frozen Ice Formations, Apostle Islands Mainland Sea Caves
Frozen ice formations coat sandstone walls inside the Apostle Islands Mainland Sea Caves on Lake Superior.
Frozen seepage forms ice curtains inside the Apostle Islands National Lakeshore Mainland Sea Caves along Lake Superior in Wisconsin. The sandstone caves are accessible on foot only when winter ice on the lake is thick enough to support visitors.
Photo taken in February 2014.
