Storm Alex was a powerful early-season

extratropical cyclone Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low-pressure areas which, along with the anticyclones of high-pressure areas, drive the weather over much of the Earth. Extratropical cyclones are capable of ...

that was particularly notable for its extreme flooding around the Mediterranean. Alex caused widespread wind and flooding damage across Europe, and at least 16 fatalities, with one more 1 person missing. Alex was the first named storm in the 2020–21 European windstorm season. Originally, a minor low-pressure system to the south west of

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...

late on 27 September. This pressure system tracked south eastwards, experiencing the

Fujiwhara effect The Fujiwhara effect, sometimes referred to as the Fujiwara effect, Fujiw(h)ara interaction or binary interaction, is a phenomenon that occurs when two nearby cyclonic vortices move around each other and close the distance between the circulations ...

and then undergoing

explosive cyclogenesis Explosive cyclogenesis (also referred to as a weather bomb, meteorological bomb, explosive development, bomb cyclone, or bombogenesis) is the rapid deepening of an extratropical cyclonic low-pressure area. The change in pressure needed to class ...

before making landfall in Brittany on 1 October. It was named by

AEMET The State Meteorological Agency (, AEMET) is a state agency of the Government of Spain responsible for providing weather forecast, warnings of hazardous weather and assisting the administrations in such matters. The AEMET is part of the Secretaria ...

and

Météo-France Météo-France is the French national meteorological service. Organisation The organisation was established by decree in June 1993 and is a department of the Ministry of Transportation. It is headquartered in Paris but many domestic operatio ...

on 30 September, with Red warnings being issued for wind for parts of Northern France from 16:00 CET on 1 October. The storm led to

advection In the field of physics, engineering, and earth sciences, advection is the transport of a substance or quantity by bulk motion of a fluid. The properties of that substance are carried with it. Generally the majority of the advected substance is al ...

of Mediterranean air northwards where it interacted with the coastal topography producing an extremely heavy rainfall in southeast France, known as a "Mediterranean Episode". This brought record breaking flooding and devastation to many areas in the region. The flooding in the south of France was purportedly the worst for at least 120 years, when records began.

Preparations and impact

United Kingdom

Many warnings were issued for the storm by UK

Met Office The Meteorological Office, abbreviated as the Met Office, is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy and is led by CEO Penelope E ...

. The first being issued for 30 September for heavy rain across south west Scotland. This was a yellow warning, stating the possibility of localised flooding. Further warnings were issued in the following days. Daily rainfall records were broken for many places. The highest fall reported as of 21:00 BST, the Met Office reported the maximum rainfall total to be at

Liss, Hampshire Liss (previously spelt Lys or Lyss) is a village and civil parish in the East Hampshire district of Hampshire, 3.3 miles (5.3 km) north-east of Petersfield, on the A3 road, on the West Sussex border. It covers 3,567 acres (14 km2) o ...

, with the maximum gust of being recorded at

Berry Head Berry Head is a coastal headland that forms the southern boundary of Tor Bay in Devon, England. Lying to the east of the town of Brixham, it is a national nature reserve and a local nature reserve. Berry Head To Sharkham Point is a Site of Sp ...

, Devon.

Warnings

France

Storm Alex sediment plumes Mediterranean

Departments in the south of France were particularly badly affected, with record breaking flooding and landslides. At least 5 people died.

References

External links

Eumetsat Case Study
{{Weather events in the United Kingdom 2020 meteorology 2020 natural disasters Weather events in the United Kingdom

Alex Alex is a given name. It can refer to a shortened version of Alexander, Alexandra, Alexis. People Multiple *Alex Brown (disambiguation), multiple people * Alex Gordon (disambiguation), multiple people *Alex Harris (disambiguation), multiple pe ...