Advance of Hubbard Glacier and 1986 Outburst of Russell Fiord, Alaska, U.S.A.

Mayo, L.R.

doi:10.3189/s0260305500007874

Cited by 38 publications

(55 citation statements)

References 13 publications

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“…A moraine was pushed up infront of the advancing glacier, raising inland water 25.5 m asl before the lake overflowed and cut the dam at the junction of the ice and the valley wall. The entire ice dam was removed within a few hours, with released water amounting to 5.4 10 9 m 3 and the peak discharge reaching 1.5 10 6 m 3 s -1 (Mayo, 1988(Mayo, , 1989. A similar event, though somewhat smaller, occurred in the summer of 2002.…”

Section: Floods From Marginal Ice-dammed Lakesmentioning

confidence: 98%

Jökulhlaups in Iceland: sources, release and drainage

Björnsson¹

2009

Megaflooding on Earth and Mars

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GLACIAL LAKE OUTBURST FLOODS IN MOUNTAIN ENVIRONMENTS Helgi Björnsson 1 IntroductionFloods can happen where glaciers dam lakes in mountainous areas. Occurring in both the temperate and subpolar regions of the Earth, such floods are called débâcles in the European Alps, aluviones in South America and jökulhlaups in Iceland. A dam of ice or sediment blocks the water to form a lake, while drainage is initiated by an opening of the hydraulic seal, which can be broken either suddenly or gradually. The impounded water is released directly into river channels, and has a typical discharge that is orders of magnitude higher than when running as a direct result of intense ablation. In regions with active, ice-covered volcanoes, meltwater is repeatedly released in floods from lakes that collect at subglacial hydrothermal areas. Occasionally, these floods take place without any significant prior storage of water, since ice melts instantaneously in volcanic eruptions. During the largest glacial floods in history, discharges reached 106 m3 s_1. For comparison, the meltwater that was temporarily stored in lakes at the edges of downwasting Pleistocene ice sheets was released in bursts that were only one order of magnitude larger than this, even though the enormous volumes involved may have altered the circulation of deep water in the North Atlantic Ocean of the late Pleistocene era.Glacial outbursts can have pronounced geomorphological impacts, since they scour river courses and inundate floodplains. Outbursts result in enormous erosion, for they carry huge loads of sediment and imprint the landscape, past and present, with deep canyons, channelled scabland, ridges standing parallel to the direction of flow, sediment deposited on outwash plains, coarse boulders strewn along riverbanks, kettleholes where massive ice blocks have become stranded and have melted, and breached terminal moraines. Some modern outbursts have produced flood waves in coastal waters (tsunamis). In the North Atlantic, outburst sediments dumped onto the continental shelf and slope have been transported great distances by turbid currents. Outburst floods wreak havoc along their paths, threatening people and livestock, destroying vegetated lowlands, devastating farms, disrupting infrastructure such as roads, bridges and power lines, and threatening hydroelectric plants on glacially fed rivers.Knowledge of jökulhlaup behaviour is essential for recognizing potential or imminent hazards, predicting and warning of occurrences, enacting preventive measures, assessing consequences and responding for the purpose of civil defence. The goal of this chapter is to outline and describe the following: (1) the location and geometry of glacial flood sources, including the properties of dams that impound the water; (2) the accumulation of water leading to outbursts and the conditions in which they begin; (3) the mechanisms and discharge characteristics of outbursts; and (4) case histories of floods, illustrating potential hazards.

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Section: Floods From Marginal Ice-dammed Lakesmentioning

confidence: 98%

Jökulhlaups in Iceland: sources, release and drainage

Björnsson¹

2009

Megaflooding on Earth and Mars

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“…Different studies have shown very high annual precipitation in the St. Elias Mountains. Mayo (1989) cites National Weather Service data of 2 to 6 m mean annual precipitation and the PRISM map (Daly et al, 1994) for Alaska and Yukon Territory, Canada indicates that BGS accumulation area receives between 5 and 13 m of precipitation annually. Thus, it is possible that the PTAA model underestimates accumulation.…”

Section: Variability Due To Different Mass-balance Modelsmentioning

confidence: 99%

Improving estimation of glacier volume change: a GLIMS case study of Bering Glacier System, Alaska

et al. 2008

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Abstract. The Global Land Ice Measurements from Space (GLIMS) project has developed tools and methods that can be employed by analysts to create accurate glacier outlines. To illustrate the importance of accurate glacier outlines and the effectiveness of GLIMS standards we conducted a case study on Bering Glacier System (BGS), Alaska. BGS is a complex glacier system aggregated from multiple drainage basins, numerous tributaries, and many accumulation areas. Published measurements of BGS surface area vary from 1740 to 6200 km 2 , depending on how the boundaries of this system have been defined. Utilizing GLIMS tools and standards we have completed a new outline (3630 km 2 ) and analysis of the area-altitude distribution (hypsometry) of BGS using Landsat images from 2000 and 2001 and a US Geological Survey 15-min digital elevation model. We compared this new hypsometry with three different hypsometries to illustrate the errors that result from the widely varying estimates of BGS extent. The use of different BGS hypsometries results in highly variable measures of volume change and net balance (b n ). Applying a simple hypsometrydependent mass-balance model to different hypsometries results in a b n rate range of −1.0 to −3.1 m a −1 water equivalent (W.E.), a volume change range of −3.8 to −6.7 km 3 a −1 W.E., and a near doubling in contributions to sea level equivalent, 0.011 mm a −1 to 0.019 mm a −1 . Current inaccuracies in glacier outlines hinder our ability to correctly quantify glacier change. Understanding of glacier extents can become Correspondence to: M. J. Beedle (beedlem@unbc.ca) comprehensive and accurate. Such accuracy is possible with the increasing volume of satellite imagery of glacierized regions, recent advances in tools and standards, and dedication to this important task.

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“…Although outburst floods are perhaps best known for the hazards they pose in alpine regions, they are not limited to such glaciers but are also associated with large tidewater glaciers in Alaska [Mayo, 1989] Where a valley is blocked by a glacier advancing from a tributary valley (Figure 23), the glacier-dammed lake commonly drains through a breach between the ice dam and an adjacent rock wall [Walder and Costa, 1996]. The way in which drainage begins is enigmatic.…”

mentioning

confidence: 99%

Water flow through temperate glaciers

Fountain¹,

Walder²

1998

Reviews of Geophysics

629

756

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Abstract. Understanding water movement through a glacier is fundamental to several critical issues in glaciology, including glacier dynamics, glacier-induced floods, and the prediction of runoff from glacierized drainage basins. To this end we have synthesized a conceptual model of water movement through a temperate glacier from the surface to the outlet stream. Processes that regulate the rate and distribution of water input at the glacier surface and that regulate water movement from the surface to the bed play important but commonly neglected roles in glacier hydrology. Where a glacier is covered by a layer of porous, permeable firn (the accumulation zone), the flux of water to the glacier interior varies slowly because the firn temporarily stores water and thereby smooths out variations in the supply rate. In the firn-free ablation zone, in contrast, the flux of water into the glacier depends directly The purpose of this paper is to present a conceptual model of water flow through a glacier based on a syn-

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Advance of Hubbard Glacier and 1986 Outburst of Russell Fiord, Alaska, U.S.A.

Cited by 38 publications

References 13 publications

Jökulhlaups in Iceland: sources, release and drainage

Jökulhlaups in Iceland: sources, release and drainage

Improving estimation of glacier volume change: a GLIMS case study of Bering Glacier System, Alaska

Water flow through temperate glaciers

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