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Once again, Portugal and Spain find themselves recovering from extensive inundation following Storm Claudia brought heavy rain and powerful gusts over the past seven days.

Claudia's Formation and Trajectory

The storm system formed from a region of depressed atmospheric pressure that had previously driven early season freezing temperatures and snowfall through the eastern sectors of Canada and the American north-east during the beginning of the eleventh month.

This storm journeyed east across the Atlantic over the second weekend of November before decelerating and halting to the north-west of the Iberian peninsula, caught in the trough of an progressively more wavy air current.

Impact on Iberia

Spain's Galicia area in the northwest was the first affected, with three to six inches of rain pouring down along its western coastline in just 24 hours up to Wednesday evening as a sluggish front of rain drifted across the western areas of the Iberian peninsula.

More downpours and stormy weather on Thursday last week led to floods to areas in Portugal where an older couple perished in the capital Lisbon after water from the overflowing Tagus River entered their home as they were asleep.

Stormy conditions lasted through the weekend, with a twister ripping through a outdoor lodging area and a nearby hotel in Albufeira in Portugal's south on Saturday, killing an elderly British lady and harming 28 individuals.

Extended Consequences across the European continent

The storm produced wider effects across western Europe. By pulling tropical air from the subtropical zones, the system contributed to thermometers climbing in France's south-west to 29.8C (85.6F), the state's maximum ever autumn temperature.

By last Friday, this warm and humid air mass met a chilly atmospheric body across the northern areas of the continent, creating a precipitation zone running from Ireland's west to the Russian Federation.

In the UK, this stalling band of rain produced exceptionally large precipitation amounts, causing major inundations in the Welsh region.

As Claudia progressively weakens early this week, the frigid air will push south, providing the continent its first taste of colder weather.

Parallel Events in California

The US state of California underwent a so-called atmospheric river the previous week, delivering torrential rain and high-velocity gusts that resulted in flash flooding and mudslides in areas affected by forest fires earlier this year.

More than 50mm of rain fell in southern California on Friday, with a another 50 millimetres across extensive areas of California on Saturday.

In excess of 100 millimetres of rain was deposited on coastal areas of southern California in total, attaining eight inches in total in locations at higher elevations.

An atmospheric river is a concentrated stream of hot, humid air originating from the tropics or subtropics.

Burn scar areas including Palisades and Altadena region suffered the most intense the flash flooding and earth movements, prompting evacuations.

In other parts of the state, a 71-year-old man lost his life after his vehicle was carried away from a submerged bridge, and a seven-year-old girl and her father were swept into the sea by large waves on the the state's central shoreline.