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Glacier Info - Emmons Glacier

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Emmons Glacier
Emmons Glacier, the largest on Mount Rainier, was named for Samuel Emmons who, with A.D. Wilson, made the second successful ascent of Mount Rainier. (Meany, Mount Rainier p. 308). A pamphlet published by Fred G. Plummer of Tacoma lists this glacier as Blaine for Senator James G. Blaine of Maine and it was called the Blaine Glacier by the Seattle Post Intelligencer Expedition of December, 1894. Samuel Franklin Emmons was born in Boston on May 29, 1841. He was an eminent geologist who was part of the U.S. Geological Survey exploration of the 40th parallel. He died March 28, 1911. (Reese, 2009)

STATISTICS AS OF 2015 (Beason, 2017):

Aerial Extent:
4.26 ± 0.21 square miles (11.03 ± 0.55 km2) (Rank: 1 of 29)

Debris Cover:
1.15 ± 0.07 square miles (2.98 ± 0.17 km2) (Rank: 2 of 29)

Highest Elevation (Head):
14,173 feet (4,320 m)

Lowest Elevation (Terminus):
4,892 feet (1,491 m)

Elevation Range:
9,282 feet (2,829 m)

Length:
4.77 miles (7.67 km)

Average Slope:
29°

Average Flow Direction (Flows towards):
Northeast (48°)

CHANGE IN EXTENT, 1896-2015 (Beason, 2017):
Units 1896 1913 1971 1994 2009 2015
Area, mi2 6.74 4.87 4.31 4.33 4.24 4.26
Area, km2 17.46 12.62 11.16 11.22 10.98 11.03

Area change between periods
1913 1971 1994 2009 2015
1896 -1.87 mi2
(-4.84 km2)
-2.43 mi2
(-6.30 km2)
-2.41 mi2
(-6.24 km2)
-2.50 mi2
(-6.48 km2)
-2.48 mi2
(-6.43 km2)
1913 -- -0.57 mi2
(-1.46 km2)
-0.54 mi2
(-1.40 km2)
-0.63 mi2
(-1.64 km2)
-0.62 mi2
(-1.60 km2)
1971 -- 0.02 mi2
(0.06 km2)
-0.07 mi2
(-0.18 km2)
-0.05 mi2
(-0.13 km2)
1994 -- -0.09 mi2
(-0.24 km2)
-0.08 mi2
(-0.20 km2)
2009 -- 0.02 mi2
(0.05 km2)

Percent change between periods
1913 1971 1994 2009 2015
1896 -27.7 % -36.1 % -35.7 % -37.1 % -36.8 %
1913 -- -11.6 % -11.1 % -13.0 % -12.6 %
1971 -- 0.6 % -1.6 % -1.2 %
1994 -- -2.2 % -1.7 %
2009 -- 0.4 %

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 0.5618 0.4062 0.3591 0.5304 0.3612 0.3533 0.3549
Volume, km3 2.3419 1.6932 1.4969 2.2110 1.5055 1.4728 1.4792
* = 1981 was the only year that glacial volumes have been measured. See note below.

Basal Shear Stress (τ): 3,285.02 lbs/ft2

Volume change between periods
1913 1971 1981 1994 2009 2015
1896 -0.1556 mi3
(-0.6487 km3)
-0.2027 mi3
(-0.8450 km3)
-0.0314 mi3
(-0.1309 km3)
-0.2007 mi3
(-0.8364 km3)
-0.2085 mi3
(-0.8691 km3)
-0.2070 mi3
(-0.8627 km3)
1913 -- -0.0471 mi3
(-0.1963 km3)
0.1242 mi3
(0.5178 km3)
-0.0450 mi3
(-0.1877 km3)
-0.0529 mi3
(-0.2204 km3)
-0.0513 mi3
(-0.2140 km3)
1971 -- 0.1713 mi3
(0.7142 km3)
0.0021 mi3
(0.0086 km3)
-0.0058 mi3
(-0.0241 km3)
-0.0042 mi3
(-0.0176 km3)
1981 -- -0.1693 mi3
(-0.7056 km3)
-0.1771 mi3
(-0.7382 km3)
-0.1756 mi3
(-0.7318 km3)
1994 -- -0.0078 mi3
(-0.0327 km3)
-0.0063 mi3
(-0.0262 km3)
2009 -- 0.0015 mi3
(0.0064 km3)

Percent change between periods
1913 1971 1981 1994 2009 2015
1896 -27.7 % -36.1 % -5.6 % -35.7 % -37.1 % -36.8 %
1913 -- -11.6 % 30.6 % -11.1 % -13.0 % -12.6 %
1971 -- 47.7 % 0.6 % -1.6 % -1.2 %
1981 -- -31.9 % -33.4 % -33.1 %
1994 -- -2.2 % -1.7 %
2009 -- 0.4 %

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