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Glacier Info - Cowlitz Glacier

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Cowlitz Glacier
Cowlitz is the name of many geographical features in the State of Washington including those within the National Park. The name appears in print as early as the Lewis and Clark journals of 1805 where it was written as "Cowliskee." The word is said to mean "...capturing the medicine spirit." Locations named Cowlitz begin on the Cowlitz Glacier on the southeast side of Mount Rainier and continue in the Cowlitz River, which flows south into Cowlitz County. (Reese, 2009)

STATISTICS AS OF 2015 (Beason, 2017):

Aerial Extent:
1.54 ± 0.08 square miles (3.99 ± 0.20 km2) (Rank: 7 of 29)

Debris Cover:
0.56 ± 0.03 square miles (1.44 ± 0.09 km2) (Rank: 5 of 29)

Highest Elevation (Head):
11,171 feet (3,405 m)

Lowest Elevation (Terminus):
5,281 feet (1,610 m)

Elevation Range:
5,890 feet (1,795 m)

Length:
3.62 miles (5.83 km)

Average Slope:
25°

Average Flow Direction (Flows towards):
East southeast (121°)

CHANGE IN EXTENT, 1896-2015 (Beason, 2017):
Units 1896 1913 1971 1994 2009 2015
Area, mi2 3.21 3.80 2.95 2.97 2.72 1.54
Area, km2 8.31 9.84 7.64 7.70 7.05 3.99

Area change between periods
1913 1971 1994 2009 2015
1896 0.59 mi2
(1.53 km2)
-0.26 mi2
(-0.67 km2)
-0.24 mi2
(-0.61 km2)
-0.49 mi2
(-1.26 km2)
-1.67 mi2
(-4.32 km2)
1913 -- -0.85 mi2
(-2.20 km2)
-0.83 mi2
(-2.14 km2)
-1.08 mi2
(-2.79 km2)
-2.26 mi2
(-5.85 km2)
1971 -- 0.02 mi2
(0.06 km2)
-0.23 mi2
(-0.59 km2)
-1.41 mi2
(-3.65 km2)
1994 -- -0.25 mi2
(-0.65 km2)
-1.43 mi2
(-3.71 km2)
2009 -- -1.18 mi2
(-3.06 km2)

Percent change between periods
1913 1971 1994 2009 2015
1896 18.4 % -8.1 % -7.4 % -15.2 % -52.0 %
1913 -- -22.3 % -21.8 % -28.4 % -59.4 %
1971 -- 0.8 % -7.7 % -47.8 %
1994 -- -8.4 % -48.2 %
2009 -- -43.4 %

ESTIMATED CHANGE IN VOLUME, 1896-2015 (George and Beason, 2017):
PLEASE see important notes about this, below...
Units 1896 1913 1971 1981* 1994 2009 2015
Volume, mi3 0.2671 0.3162 0.2456 0.1337 0.2474 0.2265 0.1283
Volume, km3 1.1134 1.3182 1.0236 0.5574 1.0313 0.9443 0.5347
* = 1981 was the only year that glacial volumes have been measured. See note below.

Basal Shear Stress (τ): 2,937.13 lbs/ft2

Volume change between periods
1913 1971 1981 1994 2009 2015
1896 0.0491 mi3
(0.2048 km3)
-0.0215 mi3
(-0.0898 km3)
-0.1334 mi3
(-0.5560 km3)
-0.0197 mi3
(-0.0821 km3)
-0.0406 mi3
(-0.1691 km3)
-0.1388 mi3
(-0.5787 km3)
1913 -- -0.0707 mi3
(-0.2946 km3)
-0.1825 mi3
(-0.7608 km3)
-0.0688 mi3
(-0.2869 km3)
-0.0897 mi3
(-0.3739 km3)
-0.1880 mi3
(-0.7835 km3)
1971 -- -0.1118 mi3
(-0.4662 km3)
0.0019 mi3
(0.0077 km3)
-0.0190 mi3
(-0.0793 km3)
-0.1173 mi3
(-0.4889 km3)
1981 -- 0.1137 mi3
(0.4739 km3)
0.0928 mi3
(0.3869 km3)
-0.0055 mi3
(-0.0227 km3)
1994 -- -0.0209 mi3
(-0.0870 km3)
-0.1191 mi3
(-0.4966 km3)
2009 -- -0.0983 mi3
(-0.4096 km3)

Percent change between periods
1913 1971 1981 1994 2009 2015
1896 18.4 % -8.1 % -49.9 % -7.4 % -15.2 % -52.0 %
1913 -- -22.3 % -57.7 % -21.8 % -28.4 % -59.4 %
1971 -- -45.5 % 0.8 % -7.7 % -47.8 %
1981 -- 85.0 % 69.4 % -4.1 %
1994 -- -8.4 % -48.2 %
2009 -- -43.4 %

With the exception of data in 1981, all values here are calculated estimates based on work by Driedger and Kennard (1986), which calculates glacier volumes with the following equations:

If Glacier Length (L) > 8,500 ft:


If Glacier Length (L) < 8,500 ft:


Basal shear stress (τ) is calculated as:


Where V is the calculated volume of the glacier (ft3), A is the calculated area of the glacier (ft2), ρ is the density of ice (1.779 slug/ft3), g is the acceleration of gravity (32.178 ft/s2), and α is the average slope of the glacier.

If you need a really good research project, recalculating the glacier volumes at Mount Rainier is the way to go!

NOTES:


Data References: Beason, 2017, George and Beason, 2017, Reese, 2009, and Driedger and Kennard, 1986