Edgeøya, an island in the southeastern part of the Svalbard archipelago, is defined by stark Arctic expanses and rugged terrain. Still, even here—halfway between mainland Norway and the North Pole—life persists, from mosses to polar bears. The southern lobe of Stonebreen, a glacier that flows from the Edgeøyjøkulen ice cap into the Barents Sea, gives the landscape a different kind of life. Its ice pulses like a heart.
The apparent heartbeat comes from the ice speeding up and slowing down with the seasons. This animation, based on satellite data collected between 2014 and 2022, shows how fast the glacier’s surface ice moves on average during each month. In winter and spring, the ice flows relatively slowly (pink); by late summer, it races toward the sea at speeds exceeding 1,200 meters per year in places (dark red). In summer 2020, speeds reached as high as 2,590 meters per year (23 feet per day).
In general, summer speedups are caused by meltwater that percolates from the surface down to the base of the glacier, where the ice sits on rock, explained Chad Greene, a glaciologist at NASA’s Jet Propulsion Laboratory (JPL). “When the base of a glacier becomes inundated with meltwater, water pressure at the base increases and allows the glacier to slide more easily,” he said.
Data for the animation are from the ITS_LIVE project, developed at JPL, which uses an algorithm to detect glacier speed based on surface features visible in optical and radar satellite images. In 2025, Greene and JPL colleague Alex Gardner used ITS_LIVE data to analyze the seasonal variability of hundreds of thousands of glaciers across the planet, including Stonebreen.
Stonebreen is a surging glacier, a type that cycles between stretches of relatively slow movement and sudden bursts of speed when ice can flow several times faster than usual. These surges can last anywhere from months to years. Globally, only about 1 percent of glaciers are surge-type, though in Svalbard, they are relatively widespread.
Before 2023, Stonebreen spent several years surging at high speeds after melting along its front likely destabilized the glacier, according to Gardner. Even during this surging period, the ice followed a seasonal rhythm—speeding up in summer and slowing through the winter—all while continuing its faster overall flow toward the Barents Sea.
Since 2023, however, the glacier has all but slowed to a halt, with only a short stretch in the summer when meltwater causes Stonebreen to glide across the ground. It has entered a phase of quiet, or “quiescence,” which is a normal part of the cycle for surge-type glaciers.
These seasonal heartbeat-like pulses and longer-term variations in ice flow at Stonebreen and other glaciers worldwide can be explored using the ITS_LIVE app.
Maps courtesy of Chad Greene and Alex Gardner, NASA/JPL, using data from the NASA MEaSUREs project ITS_LIVE. Story by Kathryn Hansen.
- Greene, C. A. and Gardner, A. S. (2025) Seasonal dynamics of Earth’s glaciers and ice sheets. Science, 390, 6776.
- NASA Earth Observatory (2025, December 3) Satellites Detect Seasonal Pulses in Earth’s Glaciers. Accessed February 12, 2026.
- NASA’s Jet Propulsion Laboratory (2026) ITS_LIVE. Accessed February 12, 2026.
- Noël, B., et al. (2020) Low elevation of Svalbard glaciers drives high mass loss variability. Nature Communications, 11(4597).
- Strozzi, T., et al. (2017) Frontal destabilization of Stonebreen, Edgeøya, Svalbard. The Cryosphere, 11(1) 553–566.
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