2 COOK INLET PHYSICAL
DESCRIPTION
2.1 Regional geography
Alaska Range blends almost imperceptibly with the
Cook Inlet is oriented southwest-northeast and cen-
Aleutian Range, which continues along the Lower
tered at approximately 60N latitude and 152W lon-
Inlet's western edge, with summits averaging 1,525
gitude (Fig. 1). The land surrounding Cook Inlet con-
m (5,000 ft) in elevation. However, many of the Aleu-
sists of vast tidal marshlands, rising up to piedmont
tian Mountains are much taller and are active volca-
lowlands with many lakes and ponds, to rugged gla-
noes. Of these, and within sight of Cook Inlet, are
cially carved mountains. Estuarine tidal marshes are
Mounts Spurr (3,374 m [11,070 ft]), Redoubt (3,108
prevalent at the mouths of the rivers and as large por-
m [10,197 ft]), Iliamna (3,053 m [10,016 ft]), and
tions of the bays about the Inlet. The Kenai Peninsula
Douglas (2,153 m [7,064 ft]). Mount Augustine is a
encloses Cook Inlet to the southeast. Here, the Kenai
4,025-m [13,205-ft] volcano that rises abruptly out of
Lowlands, immediately adjacent to the Inlet, is an area
the waters of the Lower Inlet as Augustine Island.
of flat marshland, lakes, and bogs that gradually rises
Extending north from Cook Inlet and enclosed by
up to rolling piedmont foothills. These lowlands and
the Talkeetna and Alaska Ranges are the Susitna Low-
foothills extend over a distance of 5065 km eastward
lands. They are a poorly drained, glaciated basin, ap-
to the Kenai Mountains, which rise to approximately
proximately 145 km long and 130 km wide, that is
1,500 m (5,000 ft) above sea level (asl).
characterized by its extensive ground moraine,
Immediately east of the state's largest city, Anchor-
outwash plains, drumlin fields, eskers, kettles, and
age, are the Chugach Mountains, which rise abruptly
swampland.
to around 2,150 m (7,000 ft) asl. The climate of the
Chugach Range is strongly influenced by its close
2.2 Cook Inlet's Head region
proximity to the Gulf of Alaska. The cold, polar air
Cook Inlet can be described as three distinct re-
masses that sweep down across Alaska's interior and
gions (the Head, the Upper Inlet, and the Lower Inlet)
collide with the Gulf's warmer, moisture-laden air pro-
(Nelson 1995). The Head, or northernmost end of the
duce over 15 m of snowfall annually.
Inlet, is composed of two long and narrow bays known
The Talkeetna Range, northeast of the Inlet, is sepa-
as Knik and Turnagain Arms (Fig. 2). Knik Arm ex-
rated from the Chugach Mountains to the south by the
tends inland approximately 50 km to the confluence
Matanuska River valley and from the Alaska Range
of the Knik and Matanuska Rivers from a line con-
to the north by the Susitna River. The Talkeetnas reach
necting Points Woronzof and MacKenzie. It ranges
2,150 m (7,000 ft) in elevation. The Alaska Range con-
from 2 to 10 km wide over its length. The upper two
tains several of the highest peaks in North America,
thirds is almost entirely exposed mudflats during low
including Denali (or Mt. McKinley 6,194 m [20,320
tide. The Port of Anchorage is located at the mouth of
ft]) and Mt. Foraker (5,304 m [17,400 ft]). However,
Ship Creek on the southeast shore of Knik Arm, ap-
aside from the several giants (fewer than 20 peaks in
proximately 7 km northeast of Point Woronzof and
the range are taller than 3,000 m), these mountains
280 km from the Gulf of Alaska. Anchorage (with a
are generally 2,1502,750 m (7,0009,000 ft) high.
population estimated at 255,000 in 1998) is nearly
Curving around to the northwest of the Inlet, the
eight times larger than the state's second largest city
3
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