Ice on Lake Superior
Posted Fri, August 7, 2009 - 11:10 PM
A fitting post, for the middle of summer.
I took these photos along the North Shore of Lake Superior (actually, in two different seasons.)
Even though the lake often ices over during the winter, there's a considerable period of time when and temperature is below freezing, but the open water is still thrown up on the rocks (or anything else near shore) by waves and wind. This leads to some nice examples of frozen spray:
More spray, on the surface of a large boulder - it's obvious how transparent it can be when very slowly accumulated.
During a cold season, the ice can freeze several feet thick. The last few winters here have been mild, so the lake ice only managed a thickness between 12 and 24 inches at the time I took these:
In our northern latitudes, the average temperature stays fairly low through February and March, even though the sun is as high as it is in September and October. The late winter months tend to have a good number of clear, cold days caused by high-pressure systems from the north and west, which means that the sun can be very bright and cause some interesting effects:
This shows an interesting tug-of-war between cold and heat. Lake waves threw spray up onto the rock, where it froze. But the exposure is vertical and south-facing, and the ice was transparent enough to allow the sun to warm the dark-colored rock, which melted the ice from the bottom up and let the water run down. The end result is a millimeter-thin, fragile shell of ice that's separated from the rock and only held in place where it joins with thicker, shaded ice.