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 MAPAREA

H U B B A R D

G L A

C I E

R

Lowell Glacier

Sewar

d G

laci

er

Malaspina

Glacier

Malaspina L

Valerie Glacier

Turner Gl

Haenke Gl

Variegated Gl

RussellF

iord

Dise

ncha

ntm

ent B

ay

Y A K U T A T B A Y

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

Situ

k R

iver

Old

Situk Cr

MT LOGAN

C A N

A D

A

UNITED S

TATES

HYDROLOGIC BASIN

BOUNDARIES

F A I R W

E A T H E R

F A U L T

Yakutat

Airport

Osier IsHaenke Is

GLA

C

IAL TERMINAL POSITION

1130AD

160+

139o140o

60o

30'

60o

59o

30'

0 10 20 30 KILOMETERS

0 20 MILES10

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. How-ever 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 world-class sport and commercial fi shery near Yakutat, Alaska.

Calving Glaciers are Unresponsive to Climate

Hubbard Glacier is defying the global para-digm of valley or mountain glacier shrinkage and retreat in response to global climate warm-ing. 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 unusu-ally 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 InteriorU.S. Geological Survey

USGS Fact Sheet 001—03January 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 Disenchant-ment 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 equilib-rium with climate. The large calving glaciers that are currently advanc-ing 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 dam-ming moraine was being squeezed higher above sea level

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Table 1. Peak discharges of largest known historic glaciallake outbursts

Location DatePeak

discharge(ft3/s)

1. Russell Lake, Alaska2. Russell Lake, Alaska3. Grimsvatn, Iceland4. Chong Kumdan, India

6. Chakachamna Lake, Alaska7. Lake George, Alaska

Peak discharge of Mississippi R.at Memphis, Tennessee

5. Berg Lake, Alaska

1986200219341939198319711958

1937

3,970,0001,850,0001,770,000

800,000600,000470,000360,000

1,980,000

0

-500

500

1,000

1,500

2,000

2,500

3,000

4,000

-3

NE

T L

AK

E O

UT

FLO

W, I

N T

HO

US

AN

DS

O

F C

UB

IC F

EE

T P

ER

SE

CO

ND

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

30 9 15 18

0

10

20

30

40

50

60

70

90

100

80

0

1

2

3

4

5

YA

KU

TA

T P

RE

CIP

ITA

TIO

N, I

N IN

CH

ES

OR

NE

T L

AK

E IN

FLO

W, I

N IN

CH

ES

PE

R D

AY

PE

R B

AS

IN A

RE

A

1986 Russell Lake2002 Russell Lake2002 Yakutat Precipitation

June 1 July 1 August 1 September 1 October 1

NE

T L

AK

E IN

FLO

W, I

N T

HO

US

AN

DS

O

F C

UB

IC F

EE

T P

ER

SE

CO

ND

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

0102030405060708090

June 10.0

0.5

2.0

1.0

1.5

RU

SS

ELL

LA

KE

SU

RF

AC

E A

LTIT

UD

E,

IN F

EE

T A

BO

VE

SE

A L

EV

EL

LAK

E V

OLU

ME

AB

OV

E S

EA

LE

VE

L,IN

CU

BIC

MIL

ES

1986

2002

100110120130140

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 out-burst 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 ow-ing 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 catastrophi-cally 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).

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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 stor-age 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, Apreliminary 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 LakeIce moraine dam site

Dise

ncha

ntm

ent

Bay

Russell

Fiord

Hubbard Glacier

1895194819882001N

Flow

Flow0

10 2 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. Geo-logical 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 uncer-tain, 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 InteriorU.S. Geological Survey

Fact Sheet 001—03January 2003

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