A RCTIC CIRCULA NO. I Notes on a trip in l6-foot ... - The Arctic Circle

VOL. XV No. 2 THE A<strong>RCTIC</strong> CIRCUL3R ?o
U ?{d_Hunt-Ige _SLeI: nelv -brg.akayay and recent rngyemgntg of ice jshnd.
liH 5
Cn 18 April 196? an R. C. A. F, reconnaissance flight from 408
Squadron saw a hut on a small ice island off the mouth of iuifClintock
Inlet. This surprising sight indicated that part of the S.'ard Hunt Ice Shelf,
where the hut had been placed in 1960, must have broken away. Photograpbe
taken on uray ?7 and June 13 showed that the galving had been extensive,
the shelf having lost about 200 square rniles I o", assurning a mean thick.
ness of 100 feet from 5 to 6 cubic miles of ice. On June 10, a ftight
rnade by G. Hattersley-Smith, in an Otter aircraft piloted by R. Dublicqrrn
along the entire front of the sheU with landings at three places, showed
the full extent of the breakaway. Air photographs taken on 19 August 196l
had not shown any changes in the ice shelf so the calving must have takea
place during the winter of l96l-62. As far as is known, it had been
restricted to the $ ard Hunt Ice Shelf, and tJre other three rnain ice shelves
off t.Le coast of Ellesrrrere IsLand had not been affected. The eastern eed
of t.he breakaway was in the same region where a large island had brokeq
off, pr e sumably in 1946,
The new part of the ice sheU that had broken away had been a
strip along almost the whole length of the sheU, about 40 miles long aad
up to 8 miles wide. Breaks, roughly at right angles to tJre coast, had
divided it into five large ice islands, with several small ones and rnany
fragments. The five large islands have been provisionally narned from
wegt to east, llrH 1, 2, 3, 4, 5, and they range in size from 28 sguare
miles (WH 2l to nearly 55 square miles (14 H 5).
Observations from ice island T 3 have shown that moverrrents of
ice islands in this region are mainly deterrnined by wind etresses and
that the prevailing drift pattern is to the west and southwest of Vv ard Hunt
Island. By June 13 the four westerrunost islands had followed tbe expected
course and moved west along the coast; WH 5 had however drifted in the
opposite direction. Presumably liH 5 was unable to r:nove past S'ard Hunt
Island under the influence of easterly or northeasterly winds, and was
therefore affected by occasional westerly winds. This contrary lrrovemeat
was of considerable interest and members of the Polar SheU Project placed
r adar r eflector s on the i s land to a s si st in tr acking it,
l. A11 measurements are in stahrte rniles.