Switch Glacier:
Tahoma Glacier
Two glaciers, Tahoma and South Tahoma, are located on the south side of the Puyallup Glacier on the west side of Mount Rainier. The glaciers are separated by Glacier Island. Tahoma Glacier is south of the Puyallup Glacier and is separated from it by the Puyallup Cleaver. (Reese, 2009)
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STATISTICS AS OF 2015 (Beason, 2017):
Aerial Extent:
2.62 ± 0.13 square miles
(6.79 ± 0.34 km2)
(Rank: 4 of 29)
Debris Cover:
0.60 ± 0.04 square miles
(1.56 ± 0.09 km2)
(Rank: 2 of 29)
Highest Elevation (Head):
14,349 feet
(4,373 m)
Lowest Elevation (Terminus):
6,155 feet
(1,876 m)
Elevation Range:
8,193 feet
(2,497 m)
Length:
4.37 miles
(7.03 km)
Average Slope:
30°
Average Flow Direction (Flows towards):
West southwest (250°)
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CHANGE IN EXTENT, 1896-2015 (Beason, 2017):
| Units |
1896 |
1913 |
1971 |
1994 |
2009 |
2015 |
| Area, mi2 |
4.64 |
3.54 |
2.94 |
2.81 |
2.62 |
2.62 |
| Area, km2 |
12.00 |
9.17 |
7.62 |
7.28 |
6.78 |
6.79 |
Area change between periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
| 1896 |
-1.09 mi2
(-2.83 km2) |
-1.69 mi2
(-4.39 km2) |
-1.82 mi2
(-4.72 km2) |
-2.02 mi2
(-5.23 km2) |
-2.01 mi2
(-5.22 km2) |
| 1913 |
-- |
-0.60 mi2
(-1.55 km2) |
-0.73 mi2
(-1.89 km2) |
-0.92 mi2
(-2.39 km2) |
-0.92 mi2
(-2.38 km2) |
| 1971 |
|
-- |
-0.13 mi2
(-0.34 km2) |
-0.33 mi2
(-0.84 km2) |
-0.32 mi2
(-0.83 km2) |
| 1994 |
|
-- |
-0.19 mi2
(-0.50 km2) |
-0.19 mi2
(-0.49 km2) |
| 2009 |
|
-- |
0.00 mi2
(0.01 km2) |
Percent change between periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
| 1896 |
-23.6 % |
-36.5 % |
-39.4 % |
-43.5 % |
-43.5 % |
| 1913 |
-- |
-16.9 % |
-20.6 % |
-26.1 % |
-26.0 % |
| 1971 |
|
-- |
-4.4 % |
-11.1 % |
-10.9 % |
| 1994 |
|
-- |
-6.9 % |
-6.8 % |
| 2009 |
|
-- |
0.2 % |
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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 |
0.3636 |
0.2778 |
0.2308 |
0.3588 |
0.2205 |
0.2052 |
0.2056 |
| Volume, km3 |
1.5155 |
1.1578 |
0.9618 |
1.4957 |
0.9191 |
0.8555 |
0.8568 |
* = 1981 was the only year that glacial volumes have been measured. See note below.
Basal Shear Stress (τ): 3,121.74 lbs/ft2
Volume change between periods
|
1913 |
1971 |
1981 |
1994 |
2009 |
2015 |
| 1896 |
-0.0858 mi3
(-0.3577 km3) |
-0.1328 mi3
(-0.5537 km3) |
-0.0047 mi3
(-0.0198 km3) |
-0.1431 mi3
(-0.5964 km3) |
-0.1583 mi3
(-0.6600 km3) |
-0.1580 mi3
(-0.6587 km3) |
| 1913 |
-- |
-0.0470 mi3
(-0.1959 km3) |
0.0811 mi3
(0.3379 km3) |
-0.0573 mi3
(-0.2386 km3) |
-0.0725 mi3
(-0.3022 km3) |
-0.0722 mi3
(-0.3010 km3) |
| 1971 |
|
-- |
0.1281 mi3
(0.5339 km3) |
-0.0102 mi3
(-0.0427 km3) |
-0.0255 mi3
(-0.1063 km3) |
-0.0252 mi3
(-0.1050 km3) |
| 1981 |
|
-- |
-0.1383 mi3
(-0.5766 km3) |
-0.1536 mi3
(-0.6402 km3) |
-0.1533 mi3
(-0.6389 km3) |
| 1994 |
|
-- |
-0.0153 mi3
(-0.0636 km3) |
-0.0149 mi3
(-0.0623 km3) |
| 2009 |
|
-- |
0.0003 mi3
(0.0013 km3) |
Percent change between periods
|
1913 |
1971 |
1981 |
1994 |
2009 |
2015 |
| 1896 |
-23.6 % |
-36.5 % |
-1.3 % |
-39.4 % |
-43.5 % |
-43.5 % |
| 1913 |
-- |
-16.9 % |
29.2 % |
-20.6 % |
-26.1 % |
-26.0 % |
| 1971 |
|
-- |
55.5 % |
-4.4 % |
-11.1 % |
-10.9 % |
| 1981 |
|
-- |
-38.5 % |
-42.8 % |
-42.7 % |
| 1994 |
|
-- |
-6.9 % |
-6.8 % |
| 2009 |
|
-- |
0.2 % |
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!
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NOTES:
Data References:
Beason, 2017,
George and Beason, 2017,
Reese, 2009, and
Driedger and Kennard, 1986