Ice rush
Ice sheets and pieces of ice that are excessively piled up due to ice drift are referred to as ice jolt (also ice displacement or ice accumulation ) .
Emergence
Ice rushes are caused by certain weather conditions, mostly on streams or rivers. When rapid warming occurs after a prolonged cold spell, in which the water bodies are frozen thicker, the plates on the water surface break. If there are no obstacles in the river, these ice sheets can easily be washed away ( drift ice ). However, if they hit a frozen sheet of ice, the ice sheets back up and can pile up both upwards and under the water towards the bottom. They occur in large rivers such as the Danube, but also in smaller ones such as the Große Krems or the Thaya in the Lower Austrian Waldviertel .
On oceans and lakes, the ice floes can be driven to the coast by persistent strong winds, temperature differences or currents , where they can pile up to form ice walls over 12 meters high. Ice rushes are known only in the northern hemisphere.
consequences
The ice rushes can grow in such a way that the water can no longer flow away and backs up, which can subsequently lead to flooding in the upper bank area. If the water pressure is so high that the ice rush breaks by itself, a tidal wave can arise below it . Since the ice bursts can also form on bridge piers, the water pressure can rise to such an extent that bridges are damaged or destroyed.
Ice bursts can often only be resolved by blasting , as conventional construction machines cannot penetrate the water. Since the ice rush is constantly in motion, processing it represents a major hazard.
On standing water, the meter-high ice can be pushed further inland and cause severe damage to buildings and trees near the coast. Witnesses report that such ice jolts made noises similar to a train or thunder .
Historic ice rushes
On the Danube :
- February 19, 2012: Damage on the Danube from drifting and stacked ice floes in the Belgrade area - particularly in the Zemun district at the confluence of the Save. 100 boats and pontoons , also floating restaurants and cargo ships were pushed away, crushed, driven off, overturned. In weeks of great cold , the Danube, Sava and Tisza had previously frozen over and were closed to all shipping from February 8, 2012, despite the use of icebreakers. A rapid increase in temperature from −20 ° C to +10 ° C triggered the ice drift.
- 1963: The last ice rush that reached the upper Danube as far as Ingolstadt.
- On March 11, 1929, the Danube from Neuburg to Passau was frozen over. The ice masses that started moving on March 11th destroyed the bridges of Großmehring and Pförring as well as the Gierseilferry between Korneuburg and Klosterneuburg . In 1929 the Danube was frozen over between the Wachau and Bratislava .
- In 1893 and 1876 there were ice rushes near Vienna.
- Two ice rushes in 1830 affected many houses in the former suburbs of Vienna. A total of 74 people were killed.
- February 29, 1784: The greatest flood of the century, caused by sudden snowmelt and ice jams! The cattle drowned all over the meadow ... Serious damage in the places on the pair!
- March 1, 1565: “The ice rush settled at Ingolstadt Castle and dammed the Danube so that people and animals had to leave the inner city. A dead stag was washed ashore on the first floor of the 'Grüner Baum' restaurant ... "
On the Thaya:
- February 21, 2017: A frost period of several weeks in the double-digit minus range was followed by a rapid thaw. This led to an ice rush in Vestenpoppen (municipality of Waidhofen an der Thaya - Land, Lower Austria). The dammed water masses threatened some houses in the village. The ice rush dissolved by itself and there was no damage.
- February 25, 2012: In Unterpertholz (municipality of Raabs an der Thaya, Lower Austria) an ice surge on the Thaya led to damage. Several properties were flooded by the dammed water. The fire brigade's blasting service came to blow up the ice rush, which was then dissolved.
Individual evidence
- ↑ a b Basic study - ice jolt problem at Krems and Thaya - short version ( Memento of the original from June 28, 2013 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. October 28, 2011, accessed January 5, 2012.
- ↑ http://www.cbc.ca/news/canada/manitoba/story/2013/05/13/mb-ochre-beach-ice-wall-manitoba.html
- ↑ Archive link ( Memento of the original from January 26, 2013 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ https://www.dukeupress.edu/Living-with-the-Coast-of-Alaska/
- ^ Weeks of extreme cold , ORF.at of February 20, 2012
- ↑ Boats collide with ice floes. (Article no longer accessible online) ( Memento of the original dated February 23, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Contribution with video, ORF.at from February 20, 2012
- ↑ Ingolstädter Zeitung of March 11th and 13th, 1929
- ↑ Heimatbuch Oberhaunstadt
- ^ J. Gerstner: History of the city of Ingolstadt . Munich 1852, p. 194
- ↑ 21.02.2017 - Natural spectacle in Vestenpoppen, ice rush led to flooding . ( bfk-waidhofen.at [accessed on February 19, 2018]).
- ↑ Thaw: ice rush in the Waldviertel - noe.ORF.at. Retrieved February 19, 2018 .
- ↑ meltdown blown up on the Thaya - noe.ORF.at. Retrieved February 19, 2018 .
Web links
- Basic study - ice collision problems at Krems and Thaya as an example of ice collisions in Lower Austria