I’ve posted before about the remains of previous structures that I come across along the trails in the Great Marsh area of the Indiana Dunes National Park. I have an interest in identifying these remains and searching for others. Sorta like a treasure hunt. Recently a friend showed me some resources for historical aerial photographs and topographical maps for the area. After a bit of work cropping and resizing various images I have been able to assemble an intresting set of overlapping depictions of the area near the Great Marsh trail.
Ice is nice, especially when it is thin ice over water.
Last Friday a brief warm up led to a lot of rain falling on still frozen ground, followed almost immediately by a “light” freeze. By “light” I mean the temperatures dropped below freezing, but not by much. The result was a lot of standing water covered by a paper thin crust of ice. These conditions will produce amazing patterns in the ice, if you can get to them before they collapse. I knew that the IDNP’s Great Marsh trail, with its saturated soil, would be a good source of some fun ice photography on this day.
Over Shallow Puddles…
The growth patterns of the ice crystals depends heavily on how deep the water is. This ice formed over a small, shallow puddle in the middle of the trail.The grasses and other material just underneath the surface of the puddle have strong effects on the way in which the water crystalizes as it freezes.
Over Receding Water
When ice forms atop larger bodies of water that are slowly draining, you end up with fragile sheets of ice suspended above the surface of the water.These suspended ice formations do not last long before collapsing.Thin sheets of ice will form along the sides of slow moving streams. The rain causes the water in the stream to rise, followed by the formation of a thin ice sheet over the shallower and slower moving water along the sides. The water level then falls out from under the ice.
Rising Methane Bubbles
Bubbles of methane rising from decaying organic material can become encased in the ice as it freezes from top to bottom.Marshes contain lots of decaying organic matter and so it is easy to spot these bubbles after a quick freeze.
Calm Water Ice
When the water is deeper than a puddle and calm with little movement, you find larger continuous blocks of ice.The presence of reeds rising up out of the water influences the patterns of ice formation.
