European windstorm

European windstorms are powerful extratropical cyclones which form as cyclonic windstorms associated with areas of low atmospheric pressure. They can occur throughout the year, but are most frequent between October and March, with peak intensity in the winter months. Deep areas of low pressure are common over the North Atlantic, and occasionally start as nor'easters off the New England coast. They frequently track across the North Atlantic Ocean towards the north of Scotland and into the Norwegian Sea, which generally minimizes the impact to inland areas; however, if the track is further south, it may cause adverse weather conditions across Central Europe, Northern Europe and especially Western Europe. The countries most commonly affected include the United Kingdom, Ireland, the Netherlands, Norway, Germany, the Faroe Islands and Iceland. The strong wind phenomena intrinsic to European windstorms, that give rise to "damage footprints" at the surface, can be placed into three categories, namely the "warm jet", the "cold jet" and the "sting jet". These phenomena vary in terms of physical mechanisms, atmospheric structure, spatial extent, duration, severity level, predictability and location relative to cyclone and fronts. On average, these storms cause economic damage of around €1.9 billion per year and insurance losses of €1.4 billion per year (1990–1998). They cause the highest amount of natural catastrophe insurance loss in Europe. Cyclogenesis of extratropical cyclones and The state of the North Atlantic Oscillation relates strongly to the frequency, intensity, and tracks of European windstorms. An enhanced number of storms have been noted over the North Atlantic region during positive NAO phases (compared to negative NAO phases) and is due to larger areas of suitable growth conditions. The occurrence of extreme North Atlantic cyclones is aligned with the NAO state during the cyclones' development phase. The strongest storms are embedded within, and form in large scale atmospheric flow.