Ice balls in a Michigan lake
My friend Casey went to Michigan last weekend to hang out with her sisters, and one thing they did was go snowshoeing/sledding at the YMCA camp where they all grew up. When they walked out to the lake, an interesting sight awaited them: a scum of ice balls floating in the water, and (presumably pushed by the wind), collected up along the shore. She brought back some photos.
It's a neat phenomenon, and I'm not really too sure what to make of it. The question is: are these concentrically zoned features, like oolites, hailstones, or the hematite concretions seen in Friday's post? Or are they fragments of lake ice that got broken up and then rounded due to abrasion and jostling against one another in the waves? I'm guessing that the first hypothesis is correct, but unfortunately I don't have any way to test it from here in DC.
Some observations: the ice balls are pretty well sorted, pretty spherical, and well rounded. The ice balls are packed closer together closer to the shore. There also seems to be a size gradient from larger ice balls close to shore (right, in the image below) to smaller ice balls out into the open water of the lake (left, in the image below). If this isn't just a trick of the camera's perspective, could this correspond to increased growth due to closer packing (and thus more time lifted up out of the water into the cold Michigan air) close to the shore?
Finally, I note that in some areas, multiple ice balls have clumped together into a larger entity, as some oolites will do. This cohesion between ice balls is potentially the first step for making a solid layer of ice that will extend out from the shore over the whole lake.
Anyone else ever seen anything like this? What's going on?
It's a neat phenomenon, and I'm not really too sure what to make of it. The question is: are these concentrically zoned features, like oolites, hailstones, or the hematite concretions seen in Friday's post? Or are they fragments of lake ice that got broken up and then rounded due to abrasion and jostling against one another in the waves? I'm guessing that the first hypothesis is correct, but unfortunately I don't have any way to test it from here in DC.
Some observations: the ice balls are pretty well sorted, pretty spherical, and well rounded. The ice balls are packed closer together closer to the shore. There also seems to be a size gradient from larger ice balls close to shore (right, in the image below) to smaller ice balls out into the open water of the lake (left, in the image below). If this isn't just a trick of the camera's perspective, could this correspond to increased growth due to closer packing (and thus more time lifted up out of the water into the cold Michigan air) close to the shore?
Finally, I note that in some areas, multiple ice balls have clumped together into a larger entity, as some oolites will do. This cohesion between ice balls is potentially the first step for making a solid layer of ice that will extend out from the shore over the whole lake.
Anyone else ever seen anything like this? What's going on?
1 Comments:
I have seen this on the Atlantic coast many times.
It happens when there's a heavy snowfall and some wind at a time when the water is cold enogh to freeze but due to motion it is prevented from doing so.
Conditions must be: Water temperature at zero deg. C., snow falling into the waves and combining together as the waves roll it along; think of it rolling a snowball on a liquid surface rather than a field, I'm sure you get the idea.
In Cape Breton this phenominon is known by local fishermen as "a Lolly".
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