While kayaking Lake Tahoe, California, we realized many different sized holes in the rocks below the waterline.?

Some rocks almost seemed hollow. It seems bubbles appeared and left a hole. What causes this to happen?

The holes are kind of rock Scattered in the mountains of Sierra Nevada. Walking just returned from touring in the Inyo National Forest. I saw those everywhere a pond or lake. They said they were caused by glaciers.

The Ben Show – Kayaking Tahoe