Wednesday 6 January 2016

Landslide kills twenty three Sheep in County Antrim, Northern Ireland.

A farmer in County Antrim, Northern Ireland has lost twenty three sheep after a landslide dumped several tonnes of rock and soil onto his land on Tuesday 5 January 2015. The incident happened on Dermot McDonnell's farm at Kilmore, near Glenariff following a day of heavy rain. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall. As well as the immediate loss of livestock the event has left a large amount of debris on the farm, including large boulders which are likely to be difficult to remove and which present a potential threat to McDonell's home and  road below the farm.

Debris on a farm in County Antrim following the 5 January 2015 landslide. Dermot McDonnell.

Ireland and the United Kingdom have been struck by a series of severe Atlantic storms this winter, bringing widespread flooding and triggering a number of landslip and subsidence events. This is due to exceptionally high temperatures over the Atlantic Ocean this year; ocean storms form due to heating of air over the sea, as the air is heated the the air pressure drops and the air rises, causing new air to rush in from outside the forming storm zone. If this zone is sufficiently large, then it will be influenced by the Coriolis Effect, which loosely speaking means the winds closer to the equator will be faster than those further away, causing the storm to rotate, clockwise in the northern hemisphere and anticlockwise in the southern hemisphere.

Whilst the high winds associated these storms is extremely dangerous, the real danger from such storms is often the flooding. Each millibar drop in air pressure can lead to a 1 cm rise in sea level, and large storms can be accompanied by storm surges several meters high. This tends to be accompanied by high levels of rainfall, caused by water picked up by the storm while still at sea, which can lead to flooding, swollen rivers and landslides; which occur when waterlogged soils on hill slopes lose their cohesion and slump downwards, over whatever happens to be in their path.

See also... Storm Desmond causes three fatalities, widespread flooding.                   Three fatalities have been confirmed in the wake of Atlantic Storm Desmond, which passed over the UK and Ireland on Saturday 5-Sunday 6 December... 500 without power after Atlantic Storm Barny hits UK and Ireland.                        About 28 500 homes have been left without power after Atlantic Storm Barny hit the UK and Ireland on Tuesday 17 November 2015. The majority of those affected... 1.3 Earthquake off the north coast of Ireland.                                                      The British Geological Survey recorded a Magnitude 1.3 Earthquake at a depth of 3 km roughly 2.5 km off the coast of Carrick-A-Rede on the north coast of Ireland...
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