ESSIC faculty specialist Kyle Duncan and associate research scientist Sinéad Farrell have a new article in press for the Annals of Glaciology about an interesting problem in measuring sea ice. Just as tectonic plates push up mountains where they meet, two pieces of sea ice push up snow ridges when they collide. These are called “pressure ridges” and the snow above the flat sea ice is called the “sail.” The article describes a new methodology to measure the height of these “sails” using the Digital Mapping System (DMS). The DMS is derived from high-resolution airborne digital camera images. The authors compared sail heights from the new DSM method to those from the Airborne Topographic Mapper (ATM) based on laser altimetry. Overall, the DSM method performed well.