How Freaking Beautiful Is That?
How does this happen?
- In the winter the cold causes the frozen soil to shrink, and cracks form.
- In the spring, the active layer melts and water seeps down into the cracks. It freezes and expands when it is chilled by the still-frozen soil. The frozen water forms wedges of ice in the soil.
- The active layer and the tops of the ice wedges melt in the summer, adding more water.
- Each winter, cracks form again in the same places, and in the spring, more water enters and enlarges the ice wedges as the freezing water expands.
- This cycle of crack, melt, and freeze enlarges the wedges year by year until the soil above them is pushed up, forming a blocky pattern of ridges on the ground called polygons.