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Once again, Portugal and Spain find themselves recovering from extensive inundation after Storm Claudia delivered heavy rain and powerful gusts last week.

Claudia's Formation and Trajectory

This weather system developed from a region of depressed atmospheric pressure that had previously ushered in early season cold and snowy conditions through the eastern sectors of the Canadian territory and the north-eastern United States during the beginning of the eleventh month.

This storm journeyed east across the Atlantic Ocean over the second weekend of November before slowing and stalling to the north-west of the Iberian peninsula, snared in a dip of an ever more meandering jet stream.

Consequences for Iberia

The northwestern Spanish region of Galicia was hit first, with three to six inches of rain pouring down along its west coast in just a single day up to Wednesday evening as a sluggish front of rain pushed across the western areas of the region.

Further showers and thunderstorms on Thursday brought flooding to Portuguese localities where a senior pair lost their lives in the city of Lisbon after water from the overflowing Tagus River entered their home as they slept.

Tempestuous weather persisted into the weekend, with a tornado ripping through a camping ground and a nearby hotel in the town of Albufeira in the Algarve region on the weekend's Saturday, fatally injuring an British woman aged 85 and harming 28 people.

Wider Effects across Europe

This system triggered more extensive impacts across the western European nations. By pulling tropical air from the subtropics, the system contributed to thermometers climbing in south-west France to nearly 30 degrees Celsius, the state's maximum ever autumn temperature.

By the following Friday, this warm and humid air mass met a frigid air system across more northern parts of Europe, creating a rainfall belt running from western Ireland to the Russian Federation.

In the Britain, this halting system of rain brought record-breaking rain accumulations, leading to significant waterlogging in the principality of Wales.

As this weather phenomenon continues to weaken at the start of the week, the cold air mass will move towards the south, delivering to Europe its initial glimpse of the winter season.

Parallel Events in the state of California

California experienced an "atmospheric river" recently, delivering heavy rain and strong winds that provoked flash flooding and debris flows in zones impacted by wildfires earlier this year.

More than 50mm of rain was recorded in the southern region of the state on last Friday, with a additional two inches broadly over the state on Saturday.

Over four inches of rain fell over coastal areas of the state's south in all, reaching 200mm overall in locations at higher elevations.

An atmospheric river is a narrow band of hot, humid air coming from the tropical or subtropical regions.

Burn scar areas including Pacific Palisades and Altadena experienced the most intense the rapid inundations and landslides, prompting evacuations.

Across California, a man in his seventies died after his car was carried away from a submerged bridge, and a seven-year-old girl and her parent were dragged into the Pacific by large waves on the California's Central Coast.