MOUNT RAINIER
GEOLOGY & WEATHER
Hello guest! [ Log In ]
Glacier Info - Winthrop 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).

Winthrop Glacier
On the northern slope of Mount Rainier this glacier was named for Theodore Winthrop who traveled by the mountain in 1853 as the region's first 'tourist.' Winthrop popularized the northwest in his book The Canoe and The Saddle. He was born in Connecticut in 1828 and was killed in Virginia on June 10, 1861, early in the Civil War. (Reese, 2009)

Switch Glacier:

STATISTICS AS OF 2021 (Beason et al., 2023):
Aerial Extent:
3.354 ± 0.177 square miles (8.688 ± 0.459 km2) (Rank: 2 of 29)
Debris Cover - Based on data from 2015 (Beason, 2017):
1.349 ± 0.009 square miles (3.494 ± 0.024 km2) (Rank: 2 of 29)
Estimated Glacier Volume: (See notes below)
0.1167 ± 0.0408 cubic miles (0.4865 ± 0.1703 km3)
Highest Elevation (Head):
14,305 feet (4,360 m)
Lowest Elevation (Terminus):
4,852 feet (1,479 m)
Elevation Range:
9,454 feet (2,882 m)
Length:
4.86 miles (7.83 km)
Average Slope:
24.48°
Average Flow Direction (direction the glacier flows towards):
North northeast (20°)
Glacier Type:
S - Glacier Head Near Summit

CHANGE IN EXTENT, 1896-2021 (Beason et al., 2023):
Units 1896 1913 1971 1994 2009 2015 2021
Area, mi2 3.179 3.932 3.719 3.839 3.095 3.466 3.354
Area, km2 8.235 10.183 9.631 9.943 8.015 8.977 8.688
Area Change Between Periods

1913 1971 1994 2009 2015 2021
18960.752 mi2
(1.949 km2)
0.539 mi2
(1.397 km2)
0.660 mi2
(1.709 km2)
-0.085 mi2
(-0.220 km2)
0.286 mi2
(0.742 km2)
0.175 mi2
(0.453 km2)
1913---0.213 mi2
(-0.552 km2)
-0.093 mi2
(-0.240 km2)
-0.837 mi2
(-2.168 km2)
-0.466 mi2
(-1.207 km2)
-0.577 mi2
(-1.495 km2)
1971--0.121 mi2
(0.312 km2)
-0.624 mi2
(-1.616 km2)
-0.253 mi2
(-0.655 km2)
-0.364 mi2
(-0.943 km2)
1994---0.745 mi2
(-1.929 km2)
-0.373 mi2
(-0.967 km2)
-0.485 mi2
(-1.255 km2)
2009--0.371 mi2
(0.962 km2)
0.260 mi2
(0.673 km2)
2015---0.111 mi2
(-0.289 km2)
Percent Change Between Periods

1913 1971 1994 2009 2015 2021
189623.66%16.96%20.75%-2.67%9.01%5.51%
1913---5.42%-2.35%-21.29%-11.85%-14.68%
1971--3.24%-16.78%-6.80%-9.79%
1994---19.40%-9.72%-12.63%
2009--12.00%8.40%
2015---3.21%

ESTIMATED CHANGE IN VOLUME, 1896-2021 (Beason et al., 2023):
PLEASE see important notes about this, below...
Glacier-specific Scaling Parameter, c:
0.025098
Units 1896 1913 1971 1994 2009 2015 2021
Volume, mi3 0.1085 0.1450 0.1344 0.1404 0.1045 0.1220 0.1167
Volume, km3 0.4521 0.6045 0.5601 0.5851 0.4357 0.5087 0.4865
Volume Change Between Periods

1913 1971 1994 2009 2015 2021
18960.037 mi3
(0.152 km3)
0.026 mi3
(0.108 km3)
0.032 mi3
(0.133 km3)
-0.004 mi3
(-0.016 km3)
0.014 mi3
(0.057 km3)
0.008 mi3
(0.034 km3)
1913---0.011 mi3
(-0.044 km3)
-0.005 mi3
(-0.019 km3)
-0.040 mi3
(-0.169 km3)
-0.023 mi3
(-0.096 km3)
-0.028 mi3
(-0.118 km3)
1971--0.006 mi3
(0.025 km3)
-0.030 mi3
(-0.124 km3)
-0.012 mi3
(-0.051 km3)
-0.018 mi3
(-0.074 km3)
1994---0.036 mi3
(-0.149 km3)
-0.018 mi3
(-0.076 km3)
-0.024 mi3
(-0.099 km3)
2009--0.018 mi3
(0.073 km3)
0.012 mi3
(0.051 km3)
2015---0.005 mi3
(-0.022 km3)
Percent Change Between Periods

1913 1971 1994 2009 2015 2021
189633.70%23.89%29.42%-3.63%12.52%7.61%
1913---7.34%-3.21%-27.92%-15.84%-19.52%
1971--4.46%-22.22%-9.18%-13.15%
1994---25.54%-13.06%-16.85%
2009--16.76%11.66%
2015---4.37%
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 Winthrop Glacier is 0.025098 (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 Winthrop Glacier in 2021, you can find the following individual volumes:
Back-calculated Dreidger and Kennard (1986) Method: 0.1177 mi3 (0.4905 km3).
Back-calculated Nylen (2001) Method: 0.1157 mi3 (0.4825 km3).
Average of the two (above equation and values listed for 2021 here): 0.1167 mi3 (0.4865 km3).
Official volume estimate listed above, with error: 0.1167 ± 0.0408 mi3 (0.4865 ± 0.1703 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: