Winter operations, 1970-1971 / John C. Ayers, Norbert W. O'Hara, William L. Yocum.

ice structure of this stretch of shoreline is almost exactly the same as that
presented in Fig. 28 by Marshall (1966). From this figure a storm icefoot of
ice ridges can be observed immediately along shore. Lakeward of the icefoot is
a frozen lagoon of ice floes beyond which is located an offshore barrier bar of
ice. Figure 1 is a photograph from Marshall's work depicting the "anatomy" of
the basic shore ice structure discussed above.
This report summarizes a much larger and more detailed report, and is illustrated with selected pictures from that report. To avoid confusion in identifying pictures, each retains in parentheses the figure number that it has in
the full report.
Because this paper requires constant comparison of text or figure legend
to the appropriate color photograph, and because descriptive narrative always
refers to the slide being observed, the text and figure legends are written in
the present tense.
Because of the expense of duplicating the large number of color photos involved, the full report is being prepared in only two copies. One copy will be
presented to the Michigan Water Resources Commission as a research tool; the
other will be retained on file by the Great Lakes Research Division.
This report describes and depicts the essential stages of development of
the shore ice structures as they are understood after two winters of study.
Stages of Icefoot Formation
1. The Frozen Beach
The initial stage of icefoot formation consists of a condition in which
the beach, having been wetted by rain or spray, is subjected to freezing temperatures before its surface dries. Figure 2(5) gives a general view of the
frozen beach while Figure 3(9) shows the frozen sand surface at water's edge
where small-scale undercutting of the frozen beach is in progress.

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