Bergur Einarsson, Eyjólfur Magnússon, M. J. Roberts, Finnur Pálsson, Þorsteinn Þorsteinsson, Tómas Jøhannesson,
ABSTRACT GPS campaigns on glaciers during jökulhlaups show how subglacial floods affect glacier motion and shed light on the dynamics of such floods. Three such campaigns have been carried ... southern and western Vatnajökull, southeast Iceland, over known jökulhlaup paths. Two slowly rising jökulhlaups from Grímsvötn and two rapidly rising jökulhlaups from the western and eastern Skaftá cauldrons were ... interpreted as indicating: (1) initiation of rapidly rising jökulhlaups with a propagating subglacial pressure wave, (2) decreased ...
Tópico(s): Climate change and permafrost
2016 - Cambridge University Press | Annals of Glaciology
Mengzhen Xu, Jim Bogen, Zhaoyin Wang, Truls E. Bønsnes, Stine Gytri,
... glacier thinning and volume reduction. This paper investigates jökulhlaups emanating from the glacier‐dammed lake Øvre Messingmalmvatn ... several times been observed to drain suddenly, causing jökulhlaup outbursts into the pro‐glacial lake Rundvatnet. Varve ... from Rundvatnet. It was found that sedimentation from jökulhlaups is recognizable in the lake as distinct sand ... suspension because of the extreme hydraulic conditions of jökulhlaups. The thickest sand layer was deposited during the 2001 jökulhlaup which lasted three days and had a total ...
Tópico(s): Climate change and permafrost
2014 - Wiley | Earth Surface Processes and Landforms
Andrew J. Russell, Fiona S. Tweed, M. J. Roberts, Tim Harris, M. T. Guđmundsson, Óskar Knudsen, Philip M. Marren,
Jökulhlaups (glacial outburst floods) are frequent in glaciated terrain. Jökulhlaups exhibiting a sudden rise to peak discharge have ... contact with the glacier bed. Within the glacier, jökulhlaup sedimentation occurred within hydrofractures and conduits generating complex ... sediment transport capacity controlled the locations of major jökulhlaup sedimentation. A large fan composed of material of ... ice-marginal basins filled and drained during the jökulhlaup. One of the basins, Jökulsárgil, emptied rapidly during ...
Tópico(s): Geology and Paleoclimatology Research
2010 - Elsevier BV | Quaternary Science Reviews
Abstract Jökulhlaups (glacial outburst floods) occur frequently within most glaciated regions of the world and cause rapid landscape change, infrastructure damage, and human disturbance. The largest jökulhlaups known to have occurred during the Holocene within ... along the Jökulsá á Fjöllum. Some of these jökulhlaups originated from Kverkfjöll volcano and were routed through ... preserved within these channels permit palaeoflow reconstructions. Kverkfjöll jökulhlaups were reconstructed using palaeocompetence (point measurements), slope–area ( ...
Tópico(s): Landslides and related hazards
2006 - Wiley | Hydrological Processes
Abstract Jökulhlaups (glacial outburst floods) are hazards in many glaciated environments. Jökulhlaups generated by different trigger mechanisms have different hydrograph shapes. Field evidence indicates that jökulhlaups with different hydrograph shapes produce different impacts. However, ... has been paid to understanding the controls on jökulhlaups with differing hydrograph shapes and their subsequent impacts. ... hydrographs, and none have attempted to model field jökulhlaups. This study documents the technical procedure by which ...
Tópico(s): Climate change and permafrost
2006 - Wiley | Earth Surface Processes and Landforms
Petteri Alho, Andrew J. Russell, Jonathan L. Carrivick, Jukka Käyhkö,
Glacial outburst floods (jökulhlaups) have a significant role for landscape evolution in NE Iceland. A number of jökulhlaups have routed from the northern margin of Vatnajökull ... In this study, reconstruction of the largest Holocene jökulhlaup along Jökulsá á Fjöllum, NE Iceland was undertaken ... and field-based wash limit evidence. The largest jökulhlaup produced extensive erosional and depositional landforms across an ... s−1. Power per unit area within this jökulhlaup varied from 6 to 46,000 W m−2. Jökulhlaup hydraulics are related to geomorphogical evidence at three ...
Tópico(s): Geological formations and processes
2005 - Elsevier BV | Quaternary Science Reviews
Gareth Old, Damian Lawler, Árni Snorrason,
... discharge and suspended sediment transport (SST) during two jökulhlaups (glacier outburst floods) in the Skaftá River, south Iceland. Jökulhlaups occur frequently in many glacial environments and are ... coastal environments. However, direct high‐resolution monitoring of jökulhlaups has rarely been accomplished and hardly ever at ... downstream sequence. Here we present detailed data on jökulhlaup discharge and water quality from an intensive monitoring ... at two sites in summer 1997 when two jökulhlaups occurred. Evidence is discussed that supports the origin ...
Tópico(s): Geology and Paleoclimatology Research
2005 - Wiley | Earth Surface Processes and Landforms
Andrew J. Russell, M. J. Roberts, H. Fay, Philip M. Marren, Nigel J. Cassidy, Fiona S. Tweed, Tim Harris,
... transport budgets. Within many glacial systems outburst floods (jökulhlaups) constitute high magnitude, high frequency fluxes of meltwater ... presents a synthesis of research on recent Icelandic jökulhlaups and their geomorphological and sedimentary impact. We identify jökulhlaup impacts within subglacial, englacial and proglacial settings and ... ice sheet hydrology, sediment transfer and geomorphology. Because jökulhlaups erode, deposit, and re-work sediment simultaneously, they usually cause significant glaciological and sedimentological impacts. Jökulhlaups that propagate as subglacial flood waves often produce ...
Tópico(s): Geology and Paleoclimatology Research
2005 - Elsevier BV | Geomorphology
Jonathan L. Carrivick, Andrew J. Russell, Fiona S. Tweed,
Jökulhlaups (glacial outburst floods) are known to have drained along the Jökulsá á Fjöllum river in Iceland ... characteristics. This paper provides detailed geomorphological evidence for jökulhlaups that have routed from the Kverkfjöll ice margin ... into the Jökulsá á Fjöllum. Erosional evidence of jökulhlaups from Kverkfjöll includes gorges, cataracts, spillways, subaerial lava ... landforms have been documented previously in association with jökulhlaups. However, subaerial lava surfaces that have been scoured ...
Tópico(s): Geological formations and processes
2004 - Elsevier BV | Geomorphology
Jonathan L. Carrivick, Andrew J. Russell, Fiona S. Tweed, Dave Twigg,
Jökulhlaups (glacial outburst floods) occur frequently within Iceland and within most glaciated regions of the world. The largest jökulhlaups known to have occurred within Iceland drained from ... and flow characteristics of the Jökulsá á Fjöllum jökulhlaups. One source of meltwater into the Jökulsá á ... This paper provides detailed sedimentological evidence demonstrating that jökulhlaups have routed through Kverkfjallarani and hence from Kverkfjöll. Sedimentological evidence of jökulhlaups includes valley-fill deposits and slack water deposits. ...
Tópico(s): Methane Hydrates and Related Phenomena
2004 - Elsevier BV | Sedimentary Geology
M. J. Roberts, Andrew J. Russell, Fiona S. Tweed, Óskar Knudsen,
... sedimentary evidence for rapid englacial debris entrainment during jökulhlaups. Previous studies of jökulhlaup sedimentology have focused predominantly on proglacial impact, rather ... suggest that englacial sediment emplacement is possible during jökulhlaups. The November 1996 jökulhlaup from Skeiđarárjökull, Iceland presented one of the first ... sediments and presents a qualitative model for englacial jökulhlaup deposition. Englacial jökulhlaup deposits were contained within complex networks of upglacier‐ ...
Tópico(s): Geology and Paleoclimatology Research
2001 - Wiley | Earth Surface Processes and Landforms
Jökulhlaups drain regularly from six subglacial geothermal areas in Iceland. From Grímsvötn in Vatnajökull, jökulhlaups have occurred at 4 to 6 yearly-intervals ... 0 km 3 . Prior to that, about one jökulhlaup occurred per decade, with an estimated discharge of ... Nye’s (1976) general model of discharge of jökulhlaups gives, in many respects, satisfactory simulations for jökulhlaups from Grímsvötn the best fit being obtained for ... lake temperature). The rapid ascent of the exceptional jökulhlaup of 1938, which accompanied a volcanic eruption, can ...
Tópico(s): Hydrology and Watershed Management Studies
1992 - Cambridge University Press | Annals of Glaciology
Jökulhlaups drain regularly from six subglacial geothermal areas in Iceland. From Grímsvötn in Vatnajökull, jökulhlaups have occurred at 4 to 6 yearly-intervals ... 0 km 3 . Prior to that, about one jökulhlaup occurred per decade, with an estimated discharge of ... Nye’s (1976) general model of discharge of jökulhlaups gives, in many respects, satisfactory simulations for jökulhlaups from Grímsvötn the best fit being obtained for ... lake temperature). The rapid ascent of the exceptional jökulhlaup of 1938, which accompanied a volcanic eruption, can ...
Tópico(s): Cryospheric studies and observations
1992 - Cambridge University Press | Annals of Glaciology
David J. Blauvelt, Andrew J. Russell, Andrew R. G. Large, Fiona S. Tweed, John F. Hiemstra, Bernd Kulessa, David J. A. Evans, Richard I. Waller,
High-magnitude jökulhlaups, glacier margin position and ice-thickness have been identified as key controls on sandur evolution. Existing models however ... the subsequent modification of proglacial landsystems by repeated jökulhlaups or post-depositional modification due to melt out ... m in height emplaced during a high-magnitude jökulhlaup in 1903 and subsequently buried by jökulhlaups in 1913 and 1922. The continued melting of ... together with subsequent repeated burial, by high-magnitude jökulhlaups demonstrates that jökulhlaups may continue to serve as ...
Tópico(s): Climate change and permafrost
2020 - Elsevier BV | Geomorphology
Andrew J. Russell, Jonathan L. Carrivick, Thomas Ingeman‐Nielsen, Jacob C. Yde, Meredith Williams,
Abstract Jökulhlaups in 2007 and 2008 from an ice-dammed lake at the northern margin of Russell Glacier, West Greenland, marked the onset of a renewed jökulhlaup cycle after 20 years of stability. We present ... the first field-based examination of controls on jökulhlaup magnitude and frequency for this system. We find that Russell Glacier jökulhlaups have a much higher peak discharge than predicted ... thin ice dam that permits incomplete sealing of jökulhlaup conduits between lake drainage events. Additionally, we demonstrate ...
Tópico(s): Winter Sports Injuries and Performance
2011 - Cambridge University Press | Journal of Glaciology
... sedimentary impact of a glacial outburst flood or ‘jökulhlaup’ on an ice-contact delta topset at Russell ... ice-dammed lake in July 1987 generated a jökulhlaup with a peak discharge of ∼ 1300 m3 s− ... 6 m higher than those during typical non-jökulhlaup conditions. The delta top was dissected by the 1987 jökulhlaup causing a fan-shaped extension of the delta ... downstream reduction in sediment transport capacity. The 1987 jökulhlaup was predominantly fluidal and turbulent and had peak ... from the delta front associated with slackwater conditions. Jökulhlaup-dominated delta topsets are controlled by the geometry ...
Tópico(s): Arctic and Antarctic ice dynamics
2006 - Elsevier BV | Sedimentary Geology
In glaciated catchments, glacier‐generated floods (jökulhlaups) put human activity at risk with large, sporadic jökulhlaups accounting for most flood‐related fatalities and damage to infrastructure. In studies of jökulhlaup hydrodynamics the view predominates that floodwater travels within ... into the underside of a glacier. However, some jökulhlaups produce subglacial responses wholly inconsistent with the conventional theory of drainage. By focusing on Icelandic jökulhlaups this article reassesses how floodwater flows through glaciers. ...
Tópico(s): Climate change and permafrost
2005 - Wiley | Reviews of Geophysics
M. J. Roberts, Fiona S. Tweed, Andrew J. Russell, Óskar Knudsen, Timothy Harris,
Abstract Glacial outburst floods (jökulhlaups) occur frequently in glaciated environments, and the resultant flooding causes geomorphic change and, in some instances, damage to local infrastructure. During some jökulhlaups, floodwater is stored temporarily in ice‐marginal locations. In July 1999, a linearly rising jökulhlaup burst from Sólheimajökull, Iceland. During this remarkable event, ... attendant drainage of temporary ice‐dammed lakes during jökulhlaups has not been addressed. Consequently, this paper: (i) ...
Tópico(s): Climate change and permafrost
2003 - Wiley | Earth Surface Processes and Landforms
M. J. Roberts, Andrew J. Russell, Fiona S. Tweed, Óskar Knudsen,
Theoretical studies of glacial outburst floods (jökulhlaups) assume that: (i) intraglacial floodwater is transported efficiently in isolated conduits; (ii) intraglacial conduit enlargement operates proportionally to increasing discharge; (iii) floodwater ... during flooding. Direct field observations, together with historical jökulhlaup accounts, confirm that these theoretical assumptions are not ... and temporal changes in intraglacial floodwater routing during jökulhlaups; secondly, it identifies and explains the mechanisms controlling ...
Tópico(s): Climate change and permafrost
2000 - Wiley | Earth Surface Processes and Landforms
Fiona S. Tweed, Andrew J. Russell,
... impounded or ‘ice-dammed’ lake behaviour. The spectacular jökulhlaup (catastrophic flood) from Grímsvötn, Iceland in November 1996 ... formation and persistence are identified, and cycles of jökulhlaup activity are related to glacier fluctuations. Ice-dammed ... understanding of such mechanisms is emphasized. Controls on jökulhlaup routing and the development and character of jökulhlaup conduits are discussed and recent advances in jökulhlaup prediction, hydrograph modelling and peak discharge estimation are ...
Tópico(s): Arctic and Antarctic ice dynamics
1999 - SAGE Publishing | Progress in Physical Geography Earth and Environment
Fiona S. Tweed, Andrew J. Russell,
... impounded or 'ice-dammed' lake behaviour. The spectacular jökulhlaup (catastrophic flood) from Grímsvötn, Iceland in November 1996 ... formation and persistence are identified, and cycles of jökulhlaup activity are related to glacier fluctuations. Ice-dammed ... understanding of such mechanisms is emphasized. Controls on jökulhlaup routing and the development and character of jökulhlaup conduits are discussed and recent advances in jökulhlaup prediction, hydrograph modelling and peak discharge estimation are ...
Tópico(s): Winter Sports Injuries and Performance
1999 - SAGE Publishing | Progress in Physical Geography Earth and Environment
M. T. Guðmundsson, Helgi Björnsson, Finnur Pálsson,
Abstract A record of volumes of jökulhlaups from the subglacial Grímsvötn lake, Vatnajökull, Iceland, has been derived for the period 1934–91. The change in lake volume during jökulhlaups is estimated from the lake area, ice-cover thickness and the drop in lake level. The jökulhlaup volumes have decreased gradually during this period of ... volcanic activity and declining geothermal power. The two jökulhlaups in the 1930s each discharged about 4.5 ... 3 m 3 s −1 ). In the 1980s, jökulhlaup volumes were 0.6.-1.2 km 3 ( ...
Tópico(s): Geology and Paleoclimatology Research
1995 - Cambridge University Press | Journal of Glaciology
M. T. Guðmundsson, Helgi Björnsson, Finnur Pálsson,
Abstract A record of volumes of jökulhlaups from the subglacial Grímsvötn lake, Vatnajökull, Iceland, has been derived for the period 1934–91. The change in lake volume during jökulhlaups is estimated from the lake area, ice-cover thickness and the drop in lake level. The jökulhlaup volumes have decreased gradually during this period of ... volcanic activity and declining geothermal power. The two jökulhlaups in the 1930s each discharged about 4.5 ... 3 m 3 s −1 ). In the 1980s, jökulhlaup volumes were 0.6.-1.2 km 3 ( ...
Tópico(s): Geology and Paleoclimatology Research
1995 - Cambridge University Press | Journal of Glaciology
... in West Greenland subject to glacial outburst floods (jökulhlaups). Jökulhlaup flow conditions observed during a recent (1987) flood ... Bar front advance of 60 m during 1987 jökulhlaup occurred prior to waning stage bar dissection by ... sandur records sedimentation related to at least eight jökulhlaups, whilst lower-relief amplitude, proximal sandur sediments provide a composite record of the last high stage jökulhlaup flows. Backwater conditions during jökulhlaups have increased the rapidity of spatial variation of ...
Tópico(s): Climate change and permafrost
2009 - Elsevier BV | Sedimentary Geology
Andrew J. Russell, H. Fay, Philip M. Marren, Fiona S. Tweed, Óskar Knudsen,
... for the study of glacier outburst floods or jökulhlaups and their geomorphological and sedimentological impact. Increasing attention is being focused on large jökulhlaup channels related to both modem and ancient processes. Jökulhlaup impact within Icelandic bedrock channels has so far ... Iceland. Despite clear descriptions within Icelandic literature of jökulhlaup impact on glacier margins, there have been attempts to link jökulhlaup feeder system dynamics with processes and products in ... presents the latest research on the impacts of jökulhlaups generated by three main mechanisms: volcanic, ice-dammed ...
Tópico(s): Climate change and permafrost
2005 - Elsevier BV | Developments in quaternary science
L. C. Smith, Yongwei Sheng, Francis J. Magilligan, Norman D. Smith, Basil Gómez, Leal A. K. Mertes, William Krabill, J. B. Garvin,
The November 1996 jökulhlaup that burst from the Vatnajökull ice cap onto Skeiðarársandur was the highest-magnitude flood ever measured on the largest ... and subsequent recovery. In the Gígjukvísl, the 1996 jökulhlaup caused massive sediment deposition (up to ∼12 m) ... forming" of braided channels and bars downstream. Post-jökulhlaup recovery (1997–2001) was characterized by rapid erosion (− ... forms. In contrast, the Skeiðará displays minimal post-jökulhlaup sediment erosion in its upstream reaches and little ...
Tópico(s): Geological formations and processes
2005 - Elsevier BV | Geomorphology
Jonathan L. Carrivick, Fiona S. Tweed, Paul A. Carling, Petteri Alho, Philip M. Marren, Kate E. H. Staines, Andrew J. Russell, E. Lucy Rushmer, Robert A. Duller,
... peak discharge of a glacial outburst flood, or 'jökulhlaup', for part of the Jökulsá á Fjöllum in ... Earth.We consider that the magnitude of the jökulhlaup proposed by Howard et al. (2012) warrants much ... highlight issues with attributing landforms and sediments to jökulhlaups, and (iii) consider uncertainty regarding the timing and magnitude of jökulhlaups along the Jökulsá á Fjöllum.We argue herein ... of landforms and sediments that are attributable to jökulhlaups can be observed along the Jökulsá á Fjöllum, ...
Tópico(s): Methane Hydrates and Related Phenomena
2012 - Elsevier BV | Geomorphology
Abstract The study of jökulhlaups has advanced from describing them qualitatively to measuring systematically on site their discharge curves and source geometry, as well as ... through intraglacial conduits marked a breakthrough in understanding jökulhlaup hydraulics and has since remained a classical foundation for jökulhlaup studies. This theory described flood evolution in terms ... the flowing water. While this model successfully described jökulhlaups in which the discharge hydrograph increases more or ...
Tópico(s): Landslides and related hazards
2010 - Cambridge University Press | Journal of Glaciology
Elizabeth B. Oswald, Ellen Wohl,
A jökulhlaup burst from the head of Grasshopper Glacier in Wyoming's Wind River Mountains during early September 2003. ... This paper focuses on a portion of the jökulhlaup route where erosion of the forested banks created ... and the jams facilitated overbank deposition during the jökulhlaup. Field surveys during 2004 and 2006 documented logjam ... logjams present along the forested portions of the jökulhlaup route are larger and more closely spaced than ... stream channels that have not recently experienced a jökulhlaup; (ii) logjams are not randomly located along the ...
Tópico(s): Hydrology and Sediment Transport Processes
2008 - Elsevier BV | Geomorphology
Abstract Glacial outburst floods (jökulhlaups) destroy a significant amount of infrastructure in proglacial areas. Nevertheless, few studies have simulated extreme jökulhlaup inundation using hydraulic modelling. In this study, we demonstrate the capability of one‐dimensional jökulhlaup simulation (HEC‐RAS modelling software) and compare simulation ... potential and limitations of one‐dimensional modelling for jökulhlaup simulations. In both models, a pre‐defined hydrograph ... used as an upstream boundary condition for the jökulhlaup, which was simulated on the Möðrudalur floodplain, northeast ...
Tópico(s): Flood Risk Assessment and Management
2007 - Wiley | Hydrological Processes