Columbia Glacier (Alaska)

Columbia Glacier
Tidewater glacier
Location	Descending from the Chugach Mountains to Prince William Sound, Alaska
Coordinates	61°13′11″N 146°53′43″W / 61.21972°N 146.89528°W / 61.21972; -146.89528
Area	1,000 km2 (400 sq mi)
Length	51 kilometers (32 mi)
Thickness	550 m (1,800 ft)
Terminus	Sealevel (Prince William Sound)
Status	Retreating

The Columbia Glacier, a

The glacier twists its way through western Alaska's Chugach Mountains. The bald streak at the bottom of the mountains, called the trimline, shows this glacier has lost 1,300 feet (400 m) of thickness. It has also retreated 10.5 miles (16.9 km) since that measurement was taken.^{[citation needed]}

Retreat

The glacier's speed of retreat at the terminus reached a maximum of nearly 30 meters (98 ft) per day in 2001, when it was discharging icebergs at approximately 7 cubic kilometers (1.7 cu mi) per year; the glacier has subsequently slowed down, resulting in an increase in retreat rate. The terminus has retreated a total of 16 km (9.9 mi) at an average rate of approximately 0.6 km (0.37 mi) per year since 1982. The retreat has been accompanied by nearly 500 m (1,600 ft) of thinning at the present position of the terminus. In the next few decades it is expected to retreat another 15 km (9.3 mi), to a point where the bed of the glacier rises above sea level. Columbia Glacier's retreat should be completed around 2020. Tidewater glacier advance and retreat is not directly forced by climate (adjacent tidewater glaciers may be simultaneously advancing and retreating), but rapid retreat appears to be triggered by climate-forced long-term thinning.^[2]

Gallery

Glacier photographed in 1934

See also

• Columbia Icefield
• List of glaciers
• Columbia Peak (Alaska)

References