MOUNT RAINIER
GEOLOGY & WEATHER
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Glacier Info - Cowlitz Glacier

NOTE: The data shown here is based on the 2021 glacier update at Mount Rainier, and should be considered the most up-to-date data on glaciers at the park (2023-04-06).

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)

Switch Glacier:

STATISTICS AS OF 2021 (Beason et al., 2023):
Aerial Extent:
1.423 ± 0.077 square miles (3.685 ± 0.200 km2) (Rank: 7 of 29)
Debris Cover - Based on data from 2015 (Beason, 2017):
0.555 ± 0.006 square miles (1.438 ± 0.016 km2) (Rank: 6 of 29)
Estimated Glacier Volume: (See notes below)
0.0406 ± 0.0142 cubic miles (0.1693 ± 0.0593 km3)
Highest Elevation (Head):
11,137 feet (3,395 m)
Lowest Elevation (Terminus):
5,232 feet (1,595 m)
Elevation Range:
5,906 feet (1,800 m)
Length:
3.48 miles (5.59 km)
Average Slope:
23.18°
Average Flow Direction (direction the glacier flows towards):
East southeast (121°)
Glacier Type:
C - Cirque Glacier, or Glacier Head Starts Below Summit

CHANGE IN EXTENT, 1896-2021 (Beason et al., 2023):
Units 1896 1913 1971 1994 2009 2015 2021
Area, mi2 3.208 3.798 2.950 2.972 2.721 1.541 1.423
Area, km2 8.310 9.838 7.639 7.697 7.048 3.990 3.685
Area Change Between Periods

1913 1971 1994 2009 2015 2021
18960.590 mi2
(1.528 km2)
-0.259 mi2
(-0.670 km2)
-0.237 mi2
(-0.613 km2)
-0.487 mi2
(-1.262 km2)
-1.668 mi2
(-4.319 km2)
-1.786 mi2
(-4.625 km2)
1913---0.849 mi2
(-2.199 km2)
-0.827 mi2
(-2.141 km2)
-1.077 mi2
(-2.790 km2)
-2.258 mi2
(-5.848 km2)
-2.376 mi2
(-6.153 km2)
1971--0.022 mi2
(0.058 km2)
-0.228 mi2
(-0.592 km2)
-1.409 mi2
(-3.649 km2)
-1.527 mi2
(-3.955 km2)
1994---0.251 mi2
(-0.649 km2)
-1.431 mi2
(-3.707 km2)
-1.549 mi2
(-4.012 km2)
2009---1.180 mi2
(-3.057 km2)
-1.298 mi2
(-3.363 km2)
2015---0.118 mi2
(-0.306 km2)
Percent Change Between Periods

1913 1971 1994 2009 2015 2021
189618.39%-8.07%-7.37%-15.19%-51.98%-55.66%
1913---22.35%-21.76%-28.36%-59.44%-62.55%
1971--0.75%-7.75%-47.77%-51.77%
1994---8.44%-48.16%-52.13%
2009---43.38%-47.72%
2015---7.66%

ESTIMATED CHANGE IN VOLUME, 1896-2021 (Beason et al., 2023):
PLEASE see important notes about this, below...
Glacier-specific Scaling Parameter, c:
0.031341
Units 1896 1913 1971 1994 2009 2015 2021
Volume, mi3 0.1236 0.1557 0.1101 0.1113 0.0986 0.0453 0.0406
Volume, km3 0.5151 0.6490 0.4591 0.4639 0.4112 0.1888 0.1693
Volume Change Between Periods

1913 1971 1994 2009 2015 2021
18960.032 mi3
(0.134 km3)
-0.013 mi3
(-0.056 km3)
-0.012 mi3
(-0.051 km3)
-0.025 mi3
(-0.104 km3)
-0.078 mi3
(-0.326 km3)
-0.083 mi3
(-0.346 km3)
1913---0.046 mi3
(-0.190 km3)
-0.044 mi3
(-0.185 km3)
-0.057 mi3
(-0.238 km3)
-0.110 mi3
(-0.460 km3)
-0.115 mi3
(-0.480 km3)
1971--0.001 mi3
(0.005 km3)
-0.012 mi3
(-0.048 km3)
-0.065 mi3
(-0.270 km3)
-0.070 mi3
(-0.290 km3)
1994---0.013 mi3
(-0.053 km3)
-0.066 mi3
(-0.275 km3)
-0.071 mi3
(-0.295 km3)
2009---0.053 mi3
(-0.222 km3)
-0.058 mi3
(-0.242 km3)
2015---0.005 mi3
(-0.020 km3)
Percent Change Between Periods

1913 1971 1994 2009 2015 2021
189625.99%-10.87%-9.95%-20.18%-63.35%-67.14%
1913---29.26%-28.53%-36.65%-70.91%-73.92%
1971--1.03%-10.45%-58.88%-63.13%
1994---11.36%-59.30%-63.50%
2009---54.08%-58.83%
2015---10.33%
Important comments about the calculation of volume shown here

The calculation of glacial volume shown on this page is based on an analysis of two methods used at Mount Rainier in the past (Driedger and Kennard [1986]; and Nylen [2001]) as well as the most recent literature review for glacier area-volume scaling (Please review Beason et al. [2023] for an in-depth discussion about this issue). It should be noted that simply converting area to volume with an equation is extremely difficult and the values presented here have extremely large error margins (likely ± 35% or more). With that in mind, the values presented here should give you an estimate of the glacial volume and change in volume over time. Please use these data very carefully with those caveats.

The calcuation of the volume is as follows:

\[V_i = {(c_iA_i^{1.375}) + (c_nA_i^{1.36}) \over 2}\]

Where:
\(V_i\) = Average volume for the glacier in question (km3);
\(c_i\) = The glacier-specific scaling parameter (back-calculated from glacier area and volume in 1971 in Driedger and Kennard (1986); Method described in Beason et al. (2023). The value for the Cowlitz Glacier is 0.031341 (this is also listed above the volume graph);
\(c_n\) = The back-calculated scaling parameter from Nylen (2001) of 0.0255; and
\(A_i\) = The measured volume of the glacier in question (km2).

This is essentially an average of the back-calculated Dreidger and Kennard (1986) and Nylen (2001) methods (D&K is in the first parenthesis; Nylen in the second). For example, for the Cowlitz Glacier in 2021, you can find the following individual volumes:
Back-calculated Dreidger and Kennard (1986) Method: 0.0452 mi3 (0.1883 km3).
Back-calculated Nylen (2001) Method: 0.0360 mi3 (0.1503 km3).
Average of the two (above equation and values listed for 2021 here): 0.0406 mi3 (0.1693 km3).
Official volume estimate listed above, with error: 0.0406 ± 0.0142 mi3 (0.1693 ± 0.0593 km3).

As you can see, the D&K method tends to produce higher values and Nylen produces lower values; the average of these two methods probably estimates the glacial volume. Until further research is done in this area and we can develop a better method or equation to determine volumes, this is the method we are using to determine glacial volumes. For more information about this method, please read the methods section of Beason et al. (2023).

NOTES:

-- No Notes supplied --

RAW DATA: