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

second lagoon to Ridge C. On 2 March the width of the second lagoon was estimated by pacing to be about 80 meters.
Figure 22(93) looks southward from the shoreward side of Ridge D.
The face (lakeward edge) of Ridge D is shown in Figure 23(95). The ridge
is laden with sand except where new clean slush-spray ice is being accumulated
along the edge. The man stands on top the ice cone of a blowhole, estimated
to be 25 feet high, which was the highest point on the local ridge.
Figure 24(96) shows ice blocks, iceballs, and slush/spray ice in Ridge D,
after the sand covering had been scraped away.
On 2 and 3 March 1971 Dr. O'Hara again visited the Cook Plant site to observe particularly Ridge D and the second lagoon. It proved to be a very fortunate visit, for the spring breakup began on 3 March and his visit to Ridge D
and the second lagoon would not have been possible after 2 March. On 2 March
Ridge D was a discontinuous series of blocks, with one stretch of solid ice in
the second lagoon which gave access to a block of Ridge D offshore on the north
side of the construction site.
Figure 25(116) shows at right a large and recently active blowhole in the
face of Ridge D, while in the center, wave action is depositing new slush/spray
and iceball material in a breach of the ridge.
During this time the water was making rapid additions to the ice ridges.
The reason for this is shown in Figure 26(118); the water at the face of any exposed ridge was loaded with pancake ice, iceballs, and literally grey with slush;
air temperatures were still low and the freezing regime was still dominant,
though not so strongly as had been the case somewhat earlier in the year.
In the morning of 3 March, under a northwest breeze, the ice of the second
lagoon (between Ridges C and D) was flexing and breaking up. Figure 27(126) shows,
at about 1000, the isolated block of Ridge D which had been visited on 2 March.
The solid section of second lagoon ice that had provided access to the isolated
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