Discuss the View That Most Impacts Arising from Depression Are Local, Where as Those from Anticyclones Are Regional

Discuss the view that most impacts arising from depression are local, where as those from anticyclones are regional.

Depressions are large low pressure systems that are formed when warm air meets cold air along a polar front and warm air is squeezed into a wedge that is eventually forced above the cold air. These often move though areas fairly quickly so are generally thought of as causing local impacts. Anticyclones are the opposite too depressions in the sense that they are thought of as causing regional impacts. Anticyclones are also called blocking anticyclones as they are large but slow moving systems that can settle over a large area for a long period of time meaning that they impact regional areas. However, hazards caused by depressions and anticyclones are not always this clear cut and sometimes a depression can impact over large areas, the same goes for anticyclones.

Deep low pressure depressions are usually local as they tend to move through an area quickly so the hazard to that area is usually not that prolonged. Depressions have caused several disruptive storms over the years in the UK such as the recent St. Jude’s day storm in October 2013 which caused over £1 billion worth of damage and led to the deaths of 4 people. The storm was particularly intense with wind speeds reaching almost 100mph in places with regular gusts of 80mph leading to widespread damage across the UK in the form of travel disruption as several train lines were blocked or damaged as well as flooding and wind damage to houses and property. However, although the effects of the storm were extreme for the weather the UK usually sees during the autumn and winter, if this storm is looked at alone then the damage was mainly limited to the short term as the storm passed through the UK fairly quickly. However, although depressions are short term on their own, they have a tendency to occur frequently one after the other meaning the hazard can become more long term. The St. Jude’s day storm was the first of many deep depressions of low pressure that occurred in the UK over the winter of 2013 and 2014. Several other depressions led to more damage including a high storm surge in early December that caused several homes to collapse into the sea over one night and tide heights were recorded to be higher of the storm surge that occurred in 1953. These depressions also caused frequent coastal flooding and damage and waves that destroyed several sea fronts along the UK’s coastline. Therefore it could be argued that depressions are not local hazards but can be regional hazards if they occur frequently enough. Also these sequence of depressions led to damage that was certainly nationwide. The accumulation of flooding over the winter led to some areas becoming extremely saturated to the point where the water cannot naturally drain away. This has been the case in the Somerset levels were several villages and towns are completely cut off and have been since the last major storm in early January. The water is unable to drain away quickly so villages on the Somerset levels have only been accessible by boat for weeks now. These high levels of rainfall that caused all that were due to deep depressions of low pressure but it is clear that the effects are long term here. Therefore although depressions on their own could be seen as short term hazards when they occur one after the other, as they often do, then they could also be seen as a long term hazard.

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