Malaspina Glacier in southeastern Alaska is the planet’s largest piedmont glacier, with ice that spills from the Saint Elias Mountains’ higher elevations and spreads out like pancake batter onto the coastal plain. Though it might appear static, the glacier is “alive” with movement throughout the year, typically speeding up in spring and slowing to a crawl by winter. A new analysis by NASA scientists shows that glaciers around the world display all kinds of patterns in seasonal movement—some similar to Malaspina and some vastly different.
For decades, researchers have documented seasonal speedups and slowdowns in glacier flow, typically focusing on individual glaciers or specific regions. By analyzing millions of optical and radar satellite images collected between 2014 and 2022, glaciologists Chad Greene and Alex Gardner at NASA’s Jet Propulsion Laboratory (JPL) have mapped this variability on a global scale. The new perspective reveals how glaciers in different regions respond to seasonal warming and may help identify which ones are most vulnerable to a warming climate. Their analysis was published in November 2025 in Science.
Glacier speed is measured by tracking the motion of deep cracks called crevasses and surface debris in sequences of satellite images collected over time. Crevasse fields and other surface patterns provide unique glacial “fingerprints” that scientists track using an algorithm developed at JPL as part of the ITS_LIVE project. The team used this technique to map glacier flow at high resolution …