Movie:Jökulhlaup over Sandur Iceland
Information Page: Jökulhlaup over Sandur Iceland
|Domain:||terrestrial, hydrology, coastal|
|Keywords:||glacial outburst flow|
|Model name:||Animation model name|
|Name:||RUV, Iceland National TV|
|When:||April 14, 2010|
Grade level: High (9-12), Under graduate (13-16), Graduate / Professional
Statement: Floodwaters spilling over sandur near Eyjafjallajökull
Abstract: Here we see an aerial view of the massive floodwaters draining over the coastal plain/sandur in Iceland. This jokhulhlaup is associated with the volcanic eruption of April, 2010.
The 2nd Eyjafjallajökull volcano eruption in south Iceland for 2010. It started on 14.04.2010. GPS coordinates of the eruption: 63.629° N, 19.630° W. Video by Icelandic National TV station RÚV. Music by Ceiri Torjussen; The movie show the shallow floodwater washing over the main highway of Iceland, and washing it out in several places. There was extensive damage to farm field and local houses of the debris/ash. The shallowness of the water can also be seen from the standing waves (again).
A glacial lake outburst flood occurs when massive amounts of meltwater are dramatically released. This can be for several reasons: when a lake contained by a glacier or a moraine dam drains. One distinguishes between a ‘Jökulhlaup’, if the lake formed subglacially, or a ‘marginal lake drainage’ if it was dammed between ice and the ground. Glacial outburst flows can happen due to erosion, a buildup of water pressure, an avalanche of rock or heavy snow, an earthquake or cryoseism, volcanic eruptions under the ice, or if a large enough portion of a glacier breaks off and massively displaces the waters in a glacial lake at its base.
A jökulhlaup is thus a sub-glacial outburst flood. Jökulhlaup is an Icelandic term that has been adapted into the English language, and originally only referred to glacial outburst floods, which are triggered by volcanic eruptions, but now is accepted to describe any abrupt and large release of sub-glacial water. Glacial lakes come in various sizes, but may hold millions to hundreds of millions of cubic meters of water. Catastrophic failure of the containing ice or glacial sediment can release this water over a timespan of minutes to days. Peak flows as high as 15,000 cubic meters per second have been recorded in these events. On a downstream floodplain, inundation can spread as much as 10 kilometers wide. Both scenarios are horrific threats to lives, property and infrastructure.