MOUNT RAINIER
GEOLOGY & WEATHER
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Glacier Info - North Mowich 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).

North Mowich Glacier
This large glacier on the northwest side of Mount Rainier is separated from the Flett and Russell Glaciers by Ptarmigan Ridge on the northeast and is connected to the Edmonds Glacier on the south. It gives rise to the North Mowich River and was once called the Willis Glacier because it is below Willis Wall. Mowich is a Chinook jargon term for 'deer' or 'animal.' (Reese, 2009)

Switch Glacier:

STATISTICS AS OF 2021 (Beason et al., 2023):
Aerial Extent:
1.895 ± 0.102 square miles (4.907 ± 0.264 km2) (Rank: 5 of 29)
Debris Cover - Based on data from 2015 (Beason, 2017):
0.430 ± 0.005 square miles (1.114 ± 0.014 km2) (Rank: 7 of 29)
Estimated Glacier Volume: (See notes below)
0.0502 ± 0.0176 cubic miles (0.2091 ± 0.0732 km3)
Highest Elevation (Head):
12,189 feet (3,715 m)
Lowest Elevation (Terminus):
5,429 feet (1,655 m)
Elevation Range:
6,760 feet (2,060 m)
Length:
2.56 miles (4.12 km)
Average Slope:
25.23°
Average Flow Direction (direction the glacier flows towards):
Northwest (322°)
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 4.276 3.101 2.417 2.358 2.010 1.986 1.895
Area, km2 11.074 8.032 6.261 6.108 5.207 5.144 4.907
Area Change Between Periods

1913 1971 1994 2009 2015 2021
1896-1.174 mi2
(-3.042 km2)
-1.858 mi2
(-4.813 km2)
-1.917 mi2
(-4.966 km2)
-2.265 mi2
(-5.868 km2)
-2.290 mi2
(-5.930 km2)
-2.381 mi2
(-6.167 km2)
1913---0.684 mi2
(-1.772 km2)
-0.743 mi2
(-1.924 km2)
-1.091 mi2
(-2.826 km2)
-1.115 mi2
(-2.888 km2)
-1.207 mi2
(-3.125 km2)
1971---0.059 mi2
(-0.153 km2)
-0.407 mi2
(-1.054 km2)
-0.431 mi2
(-1.117 km2)
-0.523 mi2
(-1.354 km2)
1994---0.348 mi2
(-0.902 km2)
-0.372 mi2
(-0.964 km2)
-0.464 mi2
(-1.201 km2)
2009---0.024 mi2
(-0.062 km2)
-0.116 mi2
(-0.300 km2)
2015---0.092 mi2
(-0.237 km2)
Percent Change Between Periods

1913 1971 1994 2009 2015 2021
1896-27.47%-43.46%-44.84%-52.98%-53.55%-55.69%
1913---22.05%-23.96%-35.18%-35.96%-38.91%
1971---2.44%-16.84%-17.83%-21.62%
1994---14.76%-15.78%-19.67%
2009---1.20%-5.75%
2015---4.61%

ESTIMATED CHANGE IN VOLUME, 1896-2021 (Beason et al., 2023):
PLEASE see important notes about this, below...
Glacier-specific Scaling Parameter, c:
0.022042
Units 1896 1913 1971 1994 2009 2015 2021
Volume, mi3 0.1526 0.0984 0.0700 0.0677 0.0544 0.0535 0.0502
Volume, km3 0.6363 0.4102 0.2918 0.2821 0.2268 0.2231 0.2091
Volume Change Between Periods

1913 1971 1994 2009 2015 2021
1896-0.054 mi3
(-0.226 km3)
-0.083 mi3
(-0.344 km3)
-0.085 mi3
(-0.354 km3)
-0.098 mi3
(-0.410 km3)
-0.099 mi3
(-0.413 km3)
-0.102 mi3
(-0.427 km3)
1913---0.028 mi3
(-0.118 km3)
-0.031 mi3
(-0.128 km3)
-0.044 mi3
(-0.183 km3)
-0.045 mi3
(-0.187 km3)
-0.048 mi3
(-0.201 km3)
1971---0.002 mi3
(-0.010 km3)
-0.016 mi3
(-0.065 km3)
-0.016 mi3
(-0.069 km3)
-0.020 mi3
(-0.083 km3)
1994---0.013 mi3
(-0.055 km3)
-0.014 mi3
(-0.059 km3)
-0.018 mi3
(-0.073 km3)
2009---0.001 mi3
(-0.004 km3)
-0.004 mi3
(-0.018 km3)
2015---0.003 mi3
(-0.014 km3)
Percent Change Between Periods

1913 1971 1994 2009 2015 2021
1896-35.53%-54.14%-55.67%-64.36%-64.94%-67.13%
1913---28.87%-31.23%-44.72%-45.62%-49.02%
1971---3.32%-22.28%-23.55%-28.33%
1994---19.61%-20.92%-25.87%
2009---1.63%-7.78%
2015---6.25%
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 North Mowich Glacier is 0.022042 (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 North Mowich Glacier in 2021, you can find the following individual volumes:
Back-calculated Dreidger and Kennard (1986) Method: 0.0471 mi3 (0.1964 km3).
Back-calculated Nylen (2001) Method: 0.0532 mi3 (0.2218 km3).
Average of the two (above equation and values listed for 2021 here): 0.0502 mi3 (0.2091 km3).
Official volume estimate listed above, with error: 0.0502 ± 0.0176 mi3 (0.2091 ± 0.0732 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: