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NOTE: This page has been updated to show 2021 extents and changes
Flett Glacier
This small permanent snow field is near Ptarmigan Ridge on the northwestern slope of Mount Rainier. Professor John B. Flett of the Tacoma Public Schools was for many years one of the most enthusiastic explorers of the mountain area and had the honor of naming a number of locations on the mountain. John B. Flett was born in the Orkney Islands in 1859 and come to the United States in 1874. He graduated in 1885 from Hamilton College with first honors in chemistry, and until 1892 when he came to Tacoma, he was teacher and principal of schools in New York State. He continued this career in Tacoma but also began his botanizing work and in 1896 he went into the Olympics with a party of gold hunters. The next season he went alone, and July 20, 1897, he made his first discovery of a new species, a large and beautiful violet with kidney-shaped leaves. He was a park ranger between 1913 and 1921. (Reese, 2009)
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STATISTICS AS OF 2021 (Beason et al., 2022):
Aerial Extent:
0.140 ± 0.009 square miles
(0.363 ± 0.023 km2)
(Rank: 25 of 29)
Debris Cover (Based on Beason, 2017 - not updated in 2021):
--No appreciable debris cover in 2015--
Estimated Glacial Volume: (See notes below)
0.0017 cubic miles
(0.0070 km3)
Highest Elevation (Head):
7,951 feet
(2,423 m)
Lowest Elevation (Terminus):
7,120 feet
(2,170 m)
Elevation Range:
831 feet
(253 m)
Length:
0.41 miles
(0.66 km)
Average Slope:
20°
Average Flow Direction (Flows towards):
N (356°)
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CHANGE IN EXTENT, 1896-2015 (Beason, 2017):
| Units |
1896 |
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| Area, mi2 |
-- |
0.284 |
0.223 |
0.238 |
0.225 |
0.157 |
0.140 |
| Area, km2 |
-- |
0.737 |
0.576 |
0.615 |
0.582 |
0.406 |
0.363 |
Area change between periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| 1896 |
0.285 mi2
(0.738 km2) |
0.223 mi2
(0.577 km2) |
0.238 mi2
(0.616 km2) |
0.225 mi2
(0.583 km2) |
0.157 mi2
(0.407 km2) |
0.141 mi2
(0.364 km2) |
| 1913 |
-- |
-0.062 mi2
(-0.160 km2) |
-0.047 mi2
(-0.121 km2) |
-0.060 mi2
(-0.155 km2) |
-0.128 mi2
(-0.331 km2) |
-0.144 mi2
(-0.374 km2) |
| 1971 |
|
-- |
0.015 mi2
(0.039 km2) |
0.002 mi2
(0.006 km2) |
-0.066 mi2
(-0.171 km2) |
-0.082 mi2
(-0.214 km2) |
| 1994 |
|
-- |
-0.013 mi2
(-0.033 km2) |
-0.081 mi2
(-0.210 km2) |
-0.097 mi2
(-0.252 km2) |
| 2009 |
|
-- |
-0.068 mi2
(-0.176 km2) |
-0.085 mi2
(-0.219 km2) |
| 2015 |
|
-- |
-0.016 mi2
(-0.043 km2) |
Percent change between periods
|
1913 |
1971 |
1994 |
2009 |
2015 |
2021 |
| 1896 |
-73,689.99 % |
-57,688.45 % |
-61,577.42 % |
-58,244.26 % |
-40,624.48 % |
-36,357.54 % |
| 1913 |
-- |
-21.74 % |
-16.46 % |
-20.99 % |
-44.93 % |
-50.73 % |
| 1971 |
|
-- |
6.75 % |
0.97 % |
-29.63 % |
-37.04 % |
| 1994 |
|
-- |
-5.42 % |
-34.08 % |
-41.02 % |
| 2009 |
|
-- |
-30.30 % |
-37.64 % |
| 2015 |
|
-- |
-10.53 % |
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ESTIMATED CHANGE IN VOLUME, 1896-2021 (Beason et al., 2022; George and Beason, 2017):
PLEASE see important notes about this, below...
| Units |
1896 |
1913 |
1971 |
1981* |
1994 |
2009 |
2015 |
2021 |
| Volume, mi3 |
-- |
0.0037 |
0.0028 |
0.0014 |
0.0030 |
0.0029 |
0.0019 |
0.0017 |
| Volume, km3 |
-- |
0.0155 |
0.0118 |
0.0057 |
0.0127 |
0.0119 |
0.0079 |
0.0070 |
* = 1981 was the only year that glacial volumes have been measured. See note below.
Basal Shear Stress (τ): 2,297.74 lbs/ft2
Volume change between periods
|
1913 |
1971 |
1981 |
1994 |
2009 |
2015 |
2021 |
| 1896 |
0.0037 mi3
(0.0155 km3) |
0.0028 mi3
(0.0118 km3) |
0.0014 mi3
(0.0057 km3) |
0.0030 mi3
(0.0127 km3) |
0.0029 mi3
(0.0119 km3) |
0.0019 mi3
(0.0079 km3) |
0.0017 mi3
(0.0070 km3) |
| 1913 |
-- |
-0.0009 mi3
(-0.0037 km3) |
-0.0024 mi3
(-0.0098 km3) |
-0.0007 mi3
(-0.0028 km3) |
-0.0009 mi3
(-0.0036 km3) |
-0.0018 mi3
(-0.0076 km3) |
-0.0020 mi3
(-0.0085 km3) |
| 1971 |
|
-- |
-0.0015 mi3
(-0.0061 km3) |
0.0002 mi3
(0.0009 km3) |
0.0000 mi3
(0.0001 km3) |
-0.0009 mi3
(-0.0038 km3) |
-0.0011 mi3
(-0.0048 km3) |
| 1981 |
|
-- |
0.0017 mi3
(0.0070 km3) |
0.0015 mi3
(0.0062 km3) |
0.0005 mi3
(0.0023 km3) |
0.0003 mi3
(0.0013 km3) |
| 1994 |
|
-- |
-0.0002 mi3
(-0.0008 km3) |
-0.0011 mi3
(-0.0047 km3) |
-0.0014 mi3
(-0.0057 km3) |
| 2009 |
|
-- |
-0.0010 mi3
(-0.0040 km3) |
-0.0012 mi3
(-0.0049 km3) |
| 2015 |
|
-- |
-0.0002 mi3
(-0.0009 km3) |
Percent change between periods
|
1913 |
1971 |
1981 |
1994 |
2009 |
2015 |
2021 |
| 1896 |
-1,548,715.29 % |
-1,175,691.09 % |
-566,436.00 % |
-1,265,289.72 % |
-1,188,451.71 % |
-792,077.87 % |
-698,985.79 % |
| 1913 |
-- |
-24.09 % |
-63.43 % |
-18.30 % |
-23.26 % |
-48.86 % |
-54.87 % |
| 1971 |
|
-- |
-51.83 % |
7.62 % |
1.09 % |
-32.63 % |
-40.55 % |
| 1981 |
|
-- |
123.40 % |
109.83 % |
39.84 % |
23.40 % |
| 1994 |
|
-- |
-6.07 % |
-37.40 % |
-44.76 % |
| 2009 |
|
-- |
-33.35 % |
-41.19 % |
| 2015 |
|
-- |
-11.75 % |
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:
Area was not measured for this glacier in 1896
Data References:
Beason et al., 2022,
Beason, 2017,
George and Beason, 2017,
Reese, 2009, and
Driedger and Kennard, 1986