Polygonal ground and ponds on the tundra in Noatak National Preserve, Alaska, photographed from the air.

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Preparing the 3D view

Preparing lighting and the first complete frame…

Model scale

10 m wide, 5 m deep. prescribed 0.7 m active layer. common scale.

Thaw-season phase: the active layer thaws above permafrost. Long-term wedge development 45%.

How to read these results

Play follows a prescribed year; Wedge development compares accumulated growth without assigning a rate. Ice-wedge polygons differ from frost-sorted stone circles. Neither requires a glacier on the spot.

Periglacial landforms

Explain how repeated freezing and thawing produce ice wedges and patterned ground in cold landscapes.

Drag to rotate. Hold Ctrl and scroll to zoom, or pinch on a touch screen.

Why it happens

Permafrost is ground that remains at or below 0 °C for at least two years. Seasonal thaw affects its active layer, while repeated thermal cracking and refreezing can build ice wedges.

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Ice-wedge polygons in Alaska's Noatak tundra. Repeated thermal contraction cracking and ice growth organise the permafrost landscape.

Try a comparison

Increase Wedge development and trace the tapering ice mass. Explain winter thermal contraction, crack infilling and refreezing.

Reading the result

The annual cycle and accumulated wedge width are separate comparisons; the width slider does not specify a growth rate.

A common misunderstanding

Permafrost is simply a glacier buried beneath the soil.

Permafrost is ground that remains at or below zero degrees Celsius for at least two consecutive years. It may contain ground ice, but it need not be entirely frozen water. Seasonal thaw can affect the active layer above it, while glaciers are separate bodies of accumulated, flowing ice.

Cases

Year0.40Wedge development0.45View