Landscape: Pressure Ridges

In case you haven’t noticed, this site is—in part—an exploration of place. And since I’m currently in Antarctica, this place has a lot to do with snow and ice. February marks the beginning of my twentieth month on Ross Island since 2003, but I’m finding myself endlessly fascinated with its surrounding landscape, which is really more of an icescape since Antarctica is 98% snow and ice.

By now, snow and ice could be so passé, but on a recent walk through the pressure ridges in front of Scott Base, I again remembered how seductive this place is. A pressure ridge is an ice feature that forms when tidal waves ripple a frozen ice layer that sits on top of the sea. Pressure ridges usually occur where the sea ice bumps up against an ice shelf. Sometimes the ridges become so pronounced that their crests break and create geometric displays of ice fanning out in all directions.

During the summer season in Antarctica, the pressure ridges are a dynamic landscape feature. Unlike Observation Hill, which just sits there—static—on the edge of town, the pressure ridges change shape from week to week, and revisiting them is like going to an art museum that frequently rearranges its galleries. Because warming temperatures cause the layer of ice on top of the sea to thin, the ridges become more pronounced as the season wears on.

Yesterday, as I ran on the Ob Hill Loop past an area that rippled with pressure ridges a few weeks ago, I noticed that the ridges had broken, and cluster of seals had come through the cracks to warm themselves in the sun.When I turned my back on them to head up the hill, I heard a woooosh of air and looked back to see a whale spouting breath through a pool of open water. It was one of those moments when the disparate aspects of this place all came together—the pressure ridges like ice sculptures shining in the sun, the seals—overgrown slugs—spread on top of the ice, my calves burning as I forced myself to scurry up a scree-covered hill.