Images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) onboard NASA’s Terra satellite show how one area in South Korea transformed from mountainous forest to a world-class downhill skiing venue to get ready for the 2018 Winter Olympics.

The Jeongseon Alpine Centre was built on Mount Gariwang, chosen because it met international guidelines for the Alpine Skiing events, including Downhill, Super-G, and Alpine Combined.

These ASTER images show the area in 2013 before the Jeongseon Alpine Centre was built, in 2017 after it was completed, and finally during the Olympic Games in February 2018. The inset is an oblique view of the ski hill using ASTER data. In these pseudo-true color images, varying amounts of snow cover the ground and forests appear bright green.

An additional image from Sentinel-2B shows the ski slopes in slightly higher resolution and in natural color. Forested areas are darker, and snow-covered ground appears gray.

Approximately 58,000 trees were cleared to make room for the ski runs. More than 1,000 trees are slated to be returned once the Olympics are completed. Data from ASTER and Sentinel distributed by the USGS EROS Center will be able to monitor the mountain to see any land changes that happen after the games are over.