Ice Pattern on Pond Near Freeport, Maine

January 17, 2017

Hole_in_pond_iceIMG_1971 (2)

Photographer: Clifford Rosen
Summary Authors: Clifford Rosen; Jim Foster
On a pond near my home in Freeport, Maine, on occasion I see curious holes such as this. Less than 1 in (2.5 cm) of ice the pattern reminded me of a neuron or skeletal osteocytes. Several of these holes could be observed across the pond but none was connected to each other. This is a freshwater spring-fed pond that, as of mid-December 2016, was frozen 4 in (10 cm) thick. 

These kinds of holes sometimes referred to as an ice star, ice octopus or ice spider, are upflow holes and may be associated with springs, drainage holes, cracks, etc. In essence, water oozes from a spring, for instance, below the level of the ice through a small hole or crack and into a layer of snow covering the ice sheet that's being pushed down by the weight of a new snowfall. Water infiltrating the snow layers from the inflow hole causes the darkened veins or arms.

The central hole may remain open even when the air temperature is well below freezing. In this case, it's frozen over. The temperature was 15 F or -9.5 C when this photo was snapped. Photo taken on December 17, 2016.

Photo Details: Camera: Apple iPhone 6; Focal Length: 4.15mm (35mm equivalent: 29mm); Aperture: ƒ/2.2; Exposure Time: 0.0025 s (1/395); ISO equiv: 32.