Ablation: All processes by which snow and 

ice are lost from a glacier.

Accumulation: All processes by which snow 

and ice are added to a glacier.

ALASKA MAP

AREA

H U B B A R D

G L A C I E 

R

Lowell Glacier

Seward Glacier

Malaspina

Glacier

Malaspina L

Valerie Glacier

Turner Gl

Haenke Gl

Variegated Gl

Russell

Fiord

Disenchantment Bay

Y A K U T A T B A Y

G U L F O F A L A S K A

Situk River

Old Situk Cr

MT LOGAN

C A N A D A

UNITED STATES

HYDROLOGIC 

BASIN

BOUNDARIES

F A I R W E A T H E R F A U L T

Yakutat

Airport

Osier Is

Haenke

 Is

GLACIAL TERMINAL POSITION

1130 AD 160 +

139o 140o

60o

30'

60o

59o

30'

0 10 20 30 KILOMETERS

0 10 20 MILES

Introduction

 Hubbard Glacier, the largest calving glacier 

on the North American Continent (25 percent 

larger than Rhode Island), advanced across the 

entrance to 35-mile-long Russell Fiord (fi g.1) 

during June 2002, temporarily turning it into 

a lake. Hubbard Glacier has been advancing 

for more than 100 years and has twice closed 

the entrance to Russell Fiord during the last 

16 years by squeezing and pushing submarine 

glacial sediments across the mouth of the fi ord 

(fi gs. 2 and 3). Water fl owing into the cutoff 

fi ord from mountain streams and glacier melt 

causes the level of Russell Lake to rise. However both the 1986 and 2002 dams failed (fi g. 4) 

before the lake altitude rose enough for water to 

spill over a low pass at the far end of the fi ord 

and enter the Situk River drainage, a worldclass sport and commercial fi shery near Yakutat, 

Alaska.

Calving Glaciers are Unresponsive 

to Climate

 Hubbard Glacier is defying the global paradigm of valley or mountain glacier shrinkage 

and retreat in response to global climate warming. Hubbard Glacier is the largest of eight 

calving glaciers in Alaska that are currently 

increasing in total mass and advancing. All 

of these glaciers calve into the sea, are at the 

heads of long fi ords, have undergone retreats 

during the last 1,000 years, calve over relatively 

shallow submarine moraines, and have unusually small ablation areas compared to their 

accumulation areas. 

Figure 1. Hubbard Glacier and Russell Fiord study area.

Hubbard Glacier, Alaska: Growing and Advancing in Spite of Global 

Climate Change and the 1986 and 2002 Russell Lake Outburst Floods

U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 001—03

January 2003
Figure 2. Submarine glacial sediments emerging from the sea 

May 20, 2002. Photo by Bill Lucey, U.S. Forest Service.

Figure 3. Ice and moraine dam blocking the entrance to Russell Fiord, 

July 7, 2002. Photo by U.S. Forest Service.

Figure 4. Outburst fl ood on August 14, 2002, about 9 hours after 

Russell Lake began to lose volume. Photo by Al Grillo, Associated Press

(published with permission).

For example, Hubbard Glacier retreated about 38 miles 

between 1130 A.D. and late in the 19th century (fi g. 1). 

The fi ord bottom lies 1,300 feet below sea level under 

the glacier, shallows to a depth of 200-250 feet at the 

glacier calving terminus, and then deepens again to as 

much as 750 feet below sea level down Disenchantment Bay. The accumulation area of Hubbard Glacier is 

95 percent of the entire glacier area and, like the other 

growing calving glaciers, is far from being in equilibrium with climate.

 The large calving glaciers that are currently advancing have been discordant with climate-driven glacier 

changes for a very long time. The glaciers that are 

currently growing and advancing in the face of global 

warming were retreating throughout the Little Ice Age 

(AD1350 or 1450 to AD1900) when most glaciers 

were growing.

The 1986 and 2002 Formation and Growth of 

Russell Lake

 The 1986 closure occurred near the fi rst of June; the 2002 

closure was gradual and was complete about June 16. The 

newly closed Russell Lake basin fi lled at the average rate 

of 0.7 feet per day in both 1986 and 2002 (fi g. 5). No water 

was visibly leaking through or over the dam during the 1986 

closure. However, relatively small amounts of lake water 

overfl owed the 2002 moraine dam during most of the period 

of closure (fi g. 3). This observation suggests that the damming moraine was being squeezed higher above sea level 

2
Table 1. Peak discharges of largest known historic glacial

lake outbursts

Location Date

Peak

discharge

(ft3/s)

1. Russell Lake, Alaska

2. Russell Lake, Alaska

3. Grimsvatn, Iceland

4. Chong Kumdan, India

6. Chakachamna Lake, Alaska

7. Lake George, Alaska

Peak discharge of Mississippi R.

at Memphis, Tennessee

5. Berg Lake, Alaska

1986

2002

1934

1939

1983

1971

1958

1937

3,970,000

1,850,000

1,770,000

800,000

600,000

470,000

360,000

1,980,000

0

-500

500

1,000

1,500

2,000

2,500

3,000

4,000

-3

NET LAKE OUTFLOW, IN THOUSANDS 

OF CUBIC FEET PER SECOND

3,500

October 7-8, 1986 

Outburst

August 13-14, 2002 

Outburst

6 12 21 24 27 30 33

TIME SINCE START OF OUTBURST, IN HOURS

0 3 9 15 18

0

10

20

30

40

50

60

70

90

100

80

0

1

2

3

4

5

YAKUTAT PRECIPITATION, IN INCHES

OR NET LAKE INFLOW, IN INCHES

PER DAY PER BASIN AREA

1986 Russell Lake

2002 Russell Lake

2002 Yakutat Precipitation

June 1 July 1 August 1 September 1 October 1

NET LAKE INFLOW, IN THOUSANDS 

OF CUBIC FEET PER SECOND

Estimated level at which Russell Lake will overflow into the Situk River

0

10

20

30

40

50

60

70

80

90

June 1

0.0

0.5

2.0

1.0

1.5

RUSSELL LAKE SURFACE ALTITUDE,

IN FEET ABOVE SEA LEVEL

LAKE VOLUME ABOVE SEA LEVEL,

IN CUBIC MILES

1986

2002

100

110

120

130

140

July 1 August 1 September 1 October 1

Figure 7. Russell Lake 1986 and 2002 outburst fl oods.

The maximum recorded discharge of 

the Mississippi River upstream from the 

fl ood-control structures on the lower 

river is about 7 percent larger than the 

maximum discharge during the 2002 

outburst fl ood from Russell Lake and 

about one-half the size of the 1986 outburst fl ood from Russell Lake.

Figure 5. Filling and emptying of Russell Lake during 1986 and 2002 .

Figure 6. Russell Lake fi lling rates and 2002 precipitation at Yakutat, 

Alaska.

throughout the 2002 closure period. The volume of water fl owing into the lake can be calculated from the rates of lake level 

rise (fi g. 6). During the 1986 closure, the average infl ow rate 

was 15,000 cubic feet of water per second (ft3/s). The maximum 

rate of infl ow was about 44,000 ft3/s, which occurred on 

August 13 in response to a 2-week-long rainstorm in the area. 

During the 2002 closure, the average net infl ow rate was about 

18,700 ft3/s and the maximum rate was about 92,000 ft3/s, 

which occurred on August 12, also in response to a rainstorm 

(fi g. 6).

The 1986 and 2002 Russell 

Lake Outburst Floods

 The 1986 dam failed catastrophically during the night of October 8 

(fi g. 7) releasing a fl ood that rapidly 

accelerated to a maximum of about 

4,000,000 ft3/s about 6 hours after the 

initial failure (fi g. 7). The 2002 dam 

began to fail when the lake surface 

altitude reached about 49 feet above 

sea level (fi g. 5). A rainstorm caused 

a rapid lake rise that increased the 

volume of water fl owing over the 

moraine dam, which also increased the 

rate of erosion of the dam. The growth 

of the moraine dam by glacier fl ow 

did not keep pace with erosion and the 

dam progressively failed (fi g. 7). Dam 

failure released a fl ood that reached a 

maximum discharge of 1,850, 000 ft3/s 

about 21 hours later (about midnight 

on August 14). These two fl oods 

are the largest recorded glacial-lake 

outburst fl ood events in historical time 

(table 1).

3
Additional Reading

Mayo, L.R., 1989, Advance of Hubbard Glacier and 1986 

outburst of Russell Fiord, Alaska, U.S.A.: Annals of Glaciology, 

v. 13, p. 189-194.

Seitz, H.R., Thomas, D.S., and Tomlinson, B., 1986, The storage and release of water from a large glacier-dammed lake: 

Russell Lake near Yakutat, Alaska, 1986: U.S. Geological 

Survey Open-File Report 86–545, 10 p.

Trabant, D.C., Krimmel, R.M., and Post, A., 1991, A

preliminary forecast of the advance of Hubbard Glacier 

and its infl uence on Russell Fiord, Alaska: U.S. Geological 

Survey Water-Resources Investigations Report 90–4172, 34 p.

Cooperating Agencies:

 U.S. Forest Service

 Tongass National Forest

 648 Mission Street

 Federal Building

 Ketchikan, AK 99901-6591

 907-225-3101

 http://www.fs.fed.us/r10/tongass/

 National Park Service

 Wrangell-St. Elias National Park and Preserve

 107 Richardson Highway

 P.O. Box 439

 Copper Center, AK 99573

 907-822-5234

 http://www.nps.gov/wrst/

For more information, please contact:

 U.S. Geological Survey

 4230 University Drive, Suite 201

 Anchorage, AK 99508-4664

 907-786-7100

 http://ak.water.usgs.gov

 U.S. Geological Survey

 Glaciology

 P.O. Box 75-7300

 930 Koyukuk Drive

 Fairbanks, AK 99775-7300

 907-474-1934

 http://ak.water.usgs.gov/glaciology/

Hubbard Glacier

Disenchantment Bay

Russell Lake

Ice moraine dam site

Disenchantment 

Bay

Russell

Fiord

Hubbard Glacier

1948 1895

1988 N 2001

Flow

Flow 0

0 2 1 3 4 KILOMETERS

1 2 3 MILES

—D.C. Trabant, R.S. March, and D.S. Thomas

Figure 8. Terminus positions of Hubbard Glacier in 1895, 1948, 

1988, and 2001 showing advances during the last 106 years.

Hubbard Glacier, June 13, 1986. Photo by Rod March, U.S. Geological Survey.

Long-Term Advance and Repeat Closure of 

Russell Fiord Expected

 Hubbard Glacier has advanced at a rate of about 80 feet 

per year since 1895 (fi g. 8). Although the timing is uncertain, the prospect of the glacier continuing to advance and 

again blocking the entrance to Russell Fiord is much more 

certain.

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 001—03

January 2003

4