1 INTRODUCTION
C
ook Inlet is a 350-km-long estuary located in
the sea ice extent and character for Cook Inlet in par-
south-central Alaska. Approximately half the
ticular. The maps were based on a large array of pub-
population of Alaska resides near its shores.
lished and unpublished sources and the several inter-
Anchorage, situated near its northern end, is the state's
mittent ice maps that had been issued by the
largest city and a major center for commerce, indus-
National Weather Service (NWS). Shortly thereafter
try, recreation, and transportation. Shipping routes in
the NWS began to regularly issue Cook Inlet ice
Cook Inlet serve year-round oil and natural gas prod-
charts showing the current conditions as an aid
uction in central Cook Inlet and the import of con-
to navigation and fishing activities. As of April 1999,
sumer goods and petroleum products to the Port of
approximately 675 such charts had been archived and
Anchorage. The Port serves 80% of Alaska's pop-
are now available for analysis. One purpose of this
ulation and its four largest military bases.
publication is to present an updated time series
The marine ice environment of Cook Inlet is unique.
of the mean and extreme sea ice conditions that we
Tidal height variations at Anchorage are the second
derived from these charts. In addition, this report is a
most extreme in the world. At 9 m, they are exceeded
compilation of previously published and unpublished
only by those that occur in eastern Canada's Bay of
information on the severity of winter conditions that
Fundy. The extreme tidal range and the generally shal-
prevail in a region important for the nation's commer-
low nature of Cook Inlet produce extreme tidal cur-
cial activities. The information contained here is in-
rents as well. Tidal currents at maximum flow are typi-
tended to aid engineers, ship owners, port and gov-
cally 4 knots and have been reported to be as high as 8
ernment officials, planning agencies, and mariners in
knots. These bathymetric and oceanographic factors,
ship design and modification criteria; in planning
in combination with the winter climate, result in the
safe and efficient navigation in Cook Inlet; and in re-
production of large quantities of marine ice in Cook
gional development decision-making and contingency
Inlet that can impact human activities for substantial
planning.
periods each year.
Section 2 of this atlas provides a physical descrip-
A report by Gatto, published in 1976, was the most
tion of Cook Inlet and the surrounding region. Sec-
comprehensive information publicly available up to
tion 3 describes the Inlet's marine ice environment.
that time on the oceanography of Cook Inlet. A sec-
Section 4 contains the maps of Cook Inlet ice cover
tion of that report was devoted to the Inlet's sea ice
that we created from a quantitative analysis of the
environment. However, it wasn't until 1983, when the
NWS ice charts. Sections 5 and 6 describe the oceano-
Alaska Marine Ice Atlas (LaBelle et al.) appeared, that
graphic and climatic factors, respectively, that con-
a time series of maps became available that depicted
tribute to the ice regime of Cook Inlet.
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