Why do thermokarst lakes form in permafrost areas?

Thermokarst lakes form in permafrost areas due to the melting of ground ice, which causes the land surface to settle unevenly and create depressions.12

When the ice within the frozen ground thaws, the resulting voids or collapses create hollows that collect water, forming what are known as thaw lakes or thermokarst lakes. This process is particularly common in regions underlain by ice-rich perennially frozen silt. The thawing itself can be triggered by a variety of factors, including:1

• Climate warming: Regional increases in temperature can lead to widespread thawing of ground ice.12
• Human activity: Localized thawing may result from construction, the use of heavy vehicles, agriculture, or deforestation.2
• Vegetation changes: The natural or artificial removal of surface vegetation can expose the ground to increased heat, accelerating the melting process.1

These lakes are significant indicators of ice-rich permafrost and can occur in diverse locations, including hillsides and hilltops.1