Skaftá Glacial Outburst Flood to Reach its Peak on Wednesday

A second glacial outburst flood began in the eastern Skaftá ice cauldron under Vatnajökull glacier late Saturday evening, RÚV reports. This flood follows a smaller one that originated in the western Skaftá ice cauldron and is expected to do as much damage to local communities and farmland as the last glacial outburst flood on the Skaftá river in 2018. The Department of Civil Protection is strongly advising that travelers stay away from the area and has raised their emergency response level to Alert Phase.

Floods in Skaftá are sourced from two ice cauldrons, formed due to persistent geothermal activity beneath Vatnajökull. On average, the cauldrons drain every two years, producing floods of up to 1,500 cubic metres per second. When the interval between floods is short, the flood tends to be smaller. The eastern cauldron is responsible for the largest floods. The river has flooded at least 58 times since 1955, with each cauldron usually draining at a two-year interval.


Image courtesy of Þuríður Hallgrímsdóttir. Route 1 west of the village of Kirkjubæjarklaustur flooded during the Skaftá glacial outburst flood in 2018

Smaller Flood, Same Damage
Owing to the speed at which the glacial flood began and water level increases in the first twelve hours of the flood, experts believed that the current outburst flood would be as big as the one in 2015, which is the largest such flood on record.

Happily, flood waters have been steadily abating since late Monday evening, leading experts to revise their original predictions. Nevertheless, major and widespread flooding is still a risk in the area. At time of writing, the flow at Eldvatn lake on the Skaftá river was just over 520 m3/s [18,363 ft3/s]. Flooding is expected to reach its peak tomorrow, Wednesday September 8, and waters are expected to continue to flood the region for another day or so after that.

Unfortunately, although the flood itself is expected to be smaller than it was in previous years, experts anticipate that it will do the same level of damage to surrounding settlements and farmland. This is, in part, because recent rains and runoff from the western ice cauldron, which flooded days before, have saturated the ground. As such, flood waters are more likely to spread further than they normally would.

‘We’ll just have to cross our fingers’

Glacial outburst floods are simply an unfortunate but unavoidable part of daily life for people in the area, remarked Skaftá district manager Sandra Brá Jóhannsdóttir in an interview on Tuesday before departing on a Coast Guard surveillance flight to determine what damage the flood has incurred thus far.

Authorities were particularly concerned about the wellbeing of the sheep grazing in the surrounding valleys. Local farmers spent the morning gathering their flocks and moving them to safer pastures in the event that the flood does continue to spread. Thankfully, no significant damage to structures or livestock had been reported at time of writing. “We’ll just have to cross our fingers,” said Sandra Brá. “It’s our hope, first and foremost, that the flooding is at least still at a consistent level and that hopefully, it will start to go down so that there will be less damage that occurred [in the area] in 2018 and 2015.”

The Skaftá glacial outburst flood in 2015 caused damage in the hundreds of millions of ISK (roughly $761,000; €708,000 at the time) and ten farms suffered damage to cultivated land and pasture. In 2018, flood waters covered Route 1, west of Kirkjubæjarklaustur.

See Also: Live Footage of the Skaftá Glacial Outburst Flood

In addition to warning that roadways in the area could quickly become impassable in the coming days, the Department of Civil Defense notes that glacial outburst floods can create hydrogen sulphide pollution, which can cause damage to the mucus membranes in the respitory tract and the eyes. Travelers are strongly advised to stay away from the area, which includes the Skaftárdalur valley near the southern coastal village of Kirkjubærjarklaustur, as well as around the Skaftárjökull, Tungnárjökull, and Síðjökull glaciers.

Skaftá Glacial Flood Ends

The glacial outburst flood that has been taking place along the Skaftá river in South Iceland has mostly ended reports the Icelandic Met Office.

According to an announcement on the Met’s website, “Water discharge in Skaftá is back to normal for this time of year. The Skaftá flood is therefore mostly over.” The announcement emphasizes, however, that both discharge and water height in both the Grenlækur and Tungulækur streams are still high. It’s estimated that these will return to normal levels in a little over a week.

The Icelandic Met Office issued a travel warning about the glacial flood a week ago, and since then, part of Route 1, the Ring Road, had to be closed at Kirkjubæjarklaustur due to rising water levels.

Travelers are reminded to check road conditions at before setting out on their trips.

Travel Advisory: Glacial Flood in South Iceland

The Icelandic Met Office has issued a travel advisory for Southern Iceland, where the Skaftá river is expected to experience a glacial outburst flood (jökulhlaup) over the next few days. According to the announcement, “GPS measurements from the eastern Skaftá cauldron on Vatnajökull show that the ice-shelf above the lake is lowering. This is an early sign of the onset of an outburst flood (jökulhlaup), which will affect the river Skaftá in southern Iceland. The jökulhlaup is expected to reach the edge of Vatnajökull late on Friday 3 August, with the peak of the flood possible during the early hours of Sunday 5 August.”

Travellers are strongly advised to avoid travel near the Skaftá river during the coming days. The advisory also notes that “in addition to flooding along Skaftá, gas pollution from the floodwater could affect the region, particularly at the edge of Skaftárjökull.”

A glacial outburst flood is a subglacial outburst of water usually triggered by geothermal heating and occasionally by eruptions.

According to Hulda Rós Helgadóttir, a natural disaster expert working for the Met Office who spoke to RÚV about the event, the flooding, which began around 1:00 PM local time on Friday, started much earlier than scientists anticipated. Based on measurements and data from the last glacial outburst flood, which took place in 2015, it’s currently expected that the flood waters will take 10 – 12 hours to reach the Ring Road (Route 1).