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The Iberian nations are again recovering from widespread inundation following Storm Claudia delivered heavy rain and strong winds last week.

The Storm's Formation and Trajectory

The storm system developed from a low-pressure zone that had previously ushered in early season freezing temperatures and snowfall through eastern parts of Canada and the north-eastern United States at the start of November.

Claudia journeyed east across the Atlantic Ocean during the second weekend of November before losing momentum and stopping to the northwestern area of the Iberian peninsula, snared in a dip of an ever more meandering atmospheric river.

Impact on Spain and Portugal

Galicia in north-west Spain was initially impacted, with three to six inches of rain falling along its Atlantic coast in just one full day up to Wednesday evening as a leisurely moving system of rain crawled across the western sectors of the peninsula.

More downpours and stormy weather on Thursday last week brought flooding to Portuguese localities where an older couple perished in Lisbon after rising waters from the bursting Tagus River invaded their residence as they rested.

Unsettled atmospheric states continued into the weekend, with a violent whirlwind ripping through a outdoor lodging area and a close-by inn in the town of Albufeira in the Algarve region on Saturday, killing an elderly British lady and injuring 28 individuals.

Broader Impacts across the European continent

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 France's south-west to 29.8C (85.6F), the state's maximum ever late autumn reading.

By last Friday, this tropical air mass collided with a frigid air system across more northern parts of Europe, creating a rainfall belt extending from western Ireland to the Russian Federation.

In the United Kingdom, this stationary front of rain produced very high rainfall totals, resulting in major inundations in the principality of Wales.

As Claudia continues to weaken at the start of the week, the cold air mass will move towards the south, providing the continent its premier experience of the winter season.

Parallel Events in California, USA

The Golden State encountered a plume of tropical moisture the previous week, delivering heavy rain and strong winds that resulted in rapid flooding and debris flows in regions impacted by forest fires in the recent past.

In excess of 50 millimetres of rain was recorded in southern California on Friday, with a another 50 millimetres across extensive areas of California on Saturday last.

In excess of 100 millimetres of rain was deposited on shoreline regions of southern California in aggregate, reaching a full 200 millimetres in areas of elevated terrain.

An atmospheric river is a narrow band of hot, humid air coming from the tropics or subtropics.

Regions previously burned including Pacific Palisades and the town of Altadena experienced the worst of the flash flooding and mudslides, leading to evacuations.

Elsewhere in California, a elderly male lost his life after his vehicle was washed off a submerged bridge, and a child of seven years and her dad were swept into the ocean by powerful waves on the Central Coast.