Ice Circles on the Gunpowder River, Maryland

March 09, 2015


Photographer: J.P. Glynn
Summary Authors: J.P. Glynn; Jim Foster

The photo above shows several decorative circles in ice on a branch of the Gunpowder River, Maryland, near where it enters the Chesapeake Bay. These intriguing circles are about 6-10 ft (2-3.5 m) in diameter and consist of multiple rings or bands. It’s not know for certain what causes these circles, but it’s thought that convection beneath the surface may play a role in causing circular eddies to form and then freeze. Alternatively, it’s postulated that a small amount of water was extruded upward through small openings in the ice, perhaps when punctured by a thrown object, spreading outward before quickly freezing. Each pulse of water resulted in a different band.

Photo Details: Camera: SAMSUNG SM-N910P; Focal Length: 4.8mm (35mm equivalent: 31mm); Aperture: ƒ/2.2; Exposure Time: 0.0027 s (1/372); ISO equiv: 40.