Every two years on average a jökulhlaup happens under Vatnajökull in Iceland. As the last one was in June 2010, the present flooding is expected to be much stronger than usual. These floods happen because glacier ice is melted by hydrothermal heating and the water collects in lakes under the ice. Once a “pot” is full, it starts flowing over, down the slopes, first below ice and then over the coastal sander planes towards the sea. The floods can get very powerful, taking down bridges and submerging the coastal roads. On the glacier’s surface, the ice sinks as the water empties out, forming a cauldron, the increasing depth of which is measured by GPS to estimate the progress and volume of the flooding.
The Icelandic Civil Protection Agency has also warned travellers and mountaineers to stay away from where the river emerges from beneath Tungnaárjökull, Skaftárjökull or Síðujökull glaciers and the rivers Skaftá and Hverfisfljót. (Src: Iceland Magazine). Update 15.50 LT: The sulphurous smells have now been reported from unusually far away places: http://www.ruv.is/frett/hveralykt-berst-yfir-austurland
Warning displayed on the IMO pages: Note: Along with running water is expected a release of volcanic gases such as hydrogen sulfide and sulfur dioxide. The gas follows the prevailing winds and is carried to the northeast from Skaftá to the Eastern country.
Latest Expert’s Statements on IMO’s Hydrology page (http://www.vedur.is/#syn=vatnafar):
(Transl. by Google!)
Expert on duty, 01 Oct. 15:17: Skaftárhlaup was stated on the meter Sveinstindur at 03:30 last night, Oct. 1. Flow increase at Sveinstindur shows the fastest rate since the station was established in 1971. The first studies indicate that the flow will be one of the largest from the Skaftárkötlum. The flow was a little less than 1300 m ^ 3 / s Sveinstindur at 15:00 and still growing rapidly. At 10:00 the water reached the meter of the town Skaftárdalur and the flow measured almost 400 m^3/s at 15:00 hours. Below the Laki Valley the Skaftá river is divided into three courses – one out of Eldvatn with legs through Flögulón down Kúðafljót, one out of Eldhraun in Árkvíslum and the third runs past Kirkjubaejarklaustur. Yet is the GPS of the eastern Skaftá and shows it has sunk more than 66 meters. Last 1-2 hours has slowed down significantly, suggesting that the maximum flow out of the cauldron is reached.
Expert on duty, Sept. 30, 2015, 15:25: Eastern Skaftá Kettle continues to fall with increasing speed. This indicates that the boiler flow increased rapidly now. The subsidence of the pot is now more than 11 m which is only about 10% of total level to be looked at. Running water runs still under western Vatnajökull probably towards the channel Skaftá which is expected to have the first signs of flooding shown on Thursday morning (October 1). It takes running water for 4 hours to reach the first water meter station Sveinstindur. We expect the flow of water out of the stream to lower the Laki late on Thursday and the effects of the gel could be next week.
Aerial views over the Skaftá River sanders by Víðir Reynisson from yesterday, 29 Sept:
Live GPS, updated every 5 minutes and averaged every half hour, of the cauldron surface: http://www.vedur.is/um-vi/frettir/nr/3202
Watch it live!
You can follow the dramatic changes occurring in the Skaftá river due to the glacier river flood currently under way here. On your first visit you may have to log in. If so, the user name (‘notandi’) and password (‘lykilorð’) are available on the right-hand side of the log-in page. Once in, click on ‘Suðurland’ on the left-hand-side menu, then on ‘Skaftá við Sveinstind’. (Src.: http://icelandmonitor.mbl.is/news/nature_and_travel/2015/10/01/skafta_flood_this_could_be_very_big/) EDIT: I tried this and it did not work for me. Far better to access the data here: http://vmkerfi.vedur.is/vatn/vdv_gmap.php
Bernard Duyck has a wonderful photo of the cauldron in his post (blog Earth of Fire, see permanent link in the sidebar)
Good article on earlier jökullhlaups, with lots of photos (but the Google translation is horrible):
Can the volume and extent of jökulhlaups be predetermined to alert the public in advance?
Flood Monitoring Meters
The massive floods in December 2006 came as a surprise. One of the most affected were the White River basin in Árnessýslu, Borgarfjörður, Héraðsvötn Skagafjordur and Skjálfandafljót. Hydrological NEA, now the IMO, were gauging all these catchment areas. Only one of them, Skjalfandafljot the Aldeyjarfoss was prepared to send alerts for flooding, for the measurements to monitor potential volcanically induced floods of the northern parts of the glacier. Following the floods, the agency tasked with monitoring changing water levels suggested high water areas in Árnessýslu, Nordura in Borgarfirði and Héraðsvötn Peninsula in bays so that the meters would send an alarm if the water level exceeds a certain limit. This will be a warning for potential flooding, of course with some reservations. It was also decided to install new water level gauges in the flood zone, both to monitor flooding and give warnings. For this purpose were installed three new meters in the flood areas of the White River in Árnessýslu and Ölfusá, one meter in flood zone Nordurardalur and Borgarfirði, one recommends Eyjafjarðará, one of the flooded areas in Skjálfandafljót. Water meters have been working for long in the flood zone Héraðsvötn and been used to monitor flooding in Skagafjörður. Data from these gauging and others are available in IMO’s gauging system.
Following the floods in December 2006, the Icelandic government entrusted the Hydrological Service to map possible flood limits of the main flood zone. It became necessary first to build up a database of floods as a basis for calculations and decisions. Historical flood marks were traced, the pins were set up in key locations and their height measured in with a precise GPS device. This information was posted on detailed picture maps with the help of land information systems, but also photos taken at the floods, as well as information from landowners, were integrated in the mapping.
The IMO has been working on a project on risk assessment and risk management of river floods. Part of the project relates to the attitude of the population to flooding and land use planning in flood areas. The project is a collaboration of the University of Iceland and the Icelandic Meteorological Office. Analysis of flooding is done in geographic information systems and preliminary results indicate that it is not possible to use the flow data to determine the size of flooding.
I understand that it will rather be necessary to watch actual water levels than just the amount of water flowing as the underlying morphology (river gorges vs. plains) and the type of ground would play an important role as to how much water can be accomodated in a given area. With time, such models wil be developed that involve ground permeability, possible amounts of erosion and sedimentation, gradients, and even the weather at expected flooding times.
Enjoy! – GRANYIA
1 Oct. 2015,
15:00 GMT: Now the measurements are indicating the most likely ways of the water flows, see map left. – IMO states that, from initial observations, the ongoing jökulhlaup could be the largest to have occurred from the Skaftárkatlar cauldrons. – Heavy rains today and more forecast for the coming days will add to the floods.
17:50 GMT: Surface depth of the cauldron is 68,3 m, possibliby stagnating, which could mean that the peak outflow has been reached…
18:15 GMT: now 67.1 m, so the flow rate will possibly decrease from now on. For the areas further down the worst is still to come, though.
2 Oct. 2015
Today, the general consensus in the media is that this jökulhlaup will be one of the biggest, if not the biggest in recorded history, judging from the fast rise and the massive flow rate of up to 3000 m³/s. Of course this remains to be calculated after it has ended. The floods are muddy torrents carrying large amounts of debris, tearing off big chunks of the river banks. The bridge over Eldvatn, and also the eastern part of road 208, are now closed. Hydrologists wanting to take water samples at a station could not reach the place.
– IMO: The flow at Skaftá, Sveinstindur gauge, peaked at approx. 02:00, 2 October. According to gauging the flow amounted to just under 2100 m³/s at the peak. We can expect that the real flow, however, could have varied considerably as much water flows outside the measuring range of the station. May even assume that the flow has been about 3,000 m³/s. – The flow at the Eldvatn of Asa gauge was still rising in the morning and at 11:00 was about 2150 m³/s. It peaked at 13:00 today, 2 Oct., and was 2,200 m³/s. Much water is also running in the area outside the main water channel which will be flooded for the coming days.
– IMO: A series of photos taken yesterday from a farm at Búland, which was one of the first places up river to be affected by the flood: http://www.vedur.is/vatnafar/frodleikur/greinar/nr/3208
– Daily RUV (TV) news can be watched online here: http://www.ruv.is/nyjast/frettir
– Three webcams of the Road Department can be accessed here: http://vegasja.vegagerdin.is/?xmin=378961&ymax=435900&xmax=553861&ymin=311640
mbl.is: The Skaftá glacier river flood is now making itself well felt in areas of South Iceland. The gushing waters are causing severe damage to farmland, breaking through protective walls, and flooding entire fields. Locals have described the flow of the river as “unprecedented” and a “great natural disaster”.
Flood waters from the Eystri Skaftárketill caldera have begun to subside, and south Iceland’s bridges and roads have been spared considerable damage. RÚV reports that the bridges over Eldvatn and Kúðafljót have withstood the flood waters that began earlier this week, and appear to be subsiding. The Road and Coastal Administration is now trying to direct waters away from Route 1 between Eldvatn and Kirkjubæjarklaustur. (more)
Click on Gallery to open large views:
3. Oct. 2015
Authorities urge anyone who is in the area of caution, particularly because of toxic hydrogen sulphide that can accumulate in high concentrations, among other gasses along Skaftá banks. – Volcanic gasses, particularly notable H2S, are carried to northern Europe: During half an hour ten residents in Trondheim, Norway, contacted the police reporting a stink of rotten eggs.
– IMO: GPS station has stopped transmitting about 13:00 on 02 Oct., however the depth in the graph is given as 82,7m, much lower than the red line is showing… – The flow in Skaftá Sveinstindur is 1160 m^3/s compared to the 3,000 m^3/s at the peak.
– lhg.is: The floods are declining everywhere now but there is still a lot of water around. With scientists and representatives of the Civil Protection Department and the Police on board, a helicopter of the Coast Guard, TF-SYN, flew this morning to the flooded area near the Skaftá river. Three bridges near Skaftárdalur village were affected, the road was interrupted in four places. The electricity line of Skaftá seemed in good condition. On its way back from the research flight the helicopter received a request to save three tourists whose car got stuck near Hólaskjól.
– islandsbloggen.com: Unexpected large amounts of water have flowed into the lava field Eldhraun. On a kilometer stretch along the ring road, the water has risen so high that the distance up the road is only three inches. The Jökulhlaup is not over yet. The ice cover over Skaftárjökull’s eastern caldera has so far fallen about 74 meters and continues to drop, which means that more meltwater is still flowing from the glacier into the Skaftá river, although the flow rate has slowed down considerably. (more)
Dramatic mbl Video of an overflight (it begins with an Ad and, for me, it is very slow loading):
Images that appeared on the web today (may have been taken earlier). Click on Gallery to open larger views: