|The deeper main channel of the Chippewa River covered with "pancake" ice|
The surface of the river was beginning to freeze from the edges in toward the middle - this known as border ice. Meanwhile the current continuously pushed blocks of ice and slush downstream. The slush is technically known as frazil - it forms as semisolid ice in areas of the river where the current is too strong for the river to freeze solid. These blocks of frazil are usually referred to as pans. Some of the pans collided with and held fast to the border ice (and to each other) until the entire surface of the river was covered by ice.
|A rope made of ice|
One of the coolest features that I saw in the river was a rope of ice that formed along the edge of the accumulated ice pans. This feature formed as new pans collided with the edge and pushed part of the frazil atop the solid ice. Standing alongside the river, I could here the grating as these pans slid along the edge.
|This rope of ice crystals marks the boundary between the immobile pans of ice and the freeflowing river|
|A semi-solid accretion of ice pans on the left with unattached ice floating by on the right|
|Pans of frazil ice flow downstream until they encounter surface ice.|
|A jumble of border ice, pans, frazil, and open water.|
Next time you stop to look at a frozen river, examine it closely and you too might notice all of the unique features that went into crating that icy surface.