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Portugal and Spain are once more dealing with the consequences of widespread flooding following Tempest Claudia brought heavy rain and strong winds the previous week.

Claudia's Formation and Trajectory

This weather system originated from a region of depressed atmospheric pressure that had earlier ushered in early season cold and snowy conditions through eastern parts of Canada and the north-eastern United States during the beginning of the eleventh month.

Claudia moved eastward across the Atlantic Ocean during the second weekend of November before losing momentum and stopping to the northwestern area of the Spanish and Portuguese landmass, caught in the trough of an ever more meandering air current.

Effects in the Iberian Peninsula

Spain's Galicia area in the northwest was hit first, with a substantial 80 to 150 millimetres of rain falling along its western coastline in just a single day up to the evening of Wednesday as a leisurely moving system of rain crawled across the western sectors of the peninsula.

Additional rainfall and electrical storms on the following Thursday led to floods to parts of Portugal where an older couple perished in the city of Lisbon after floodwaters from the swollen Tagus invaded their residence as they rested.

Tempestuous weather persisted into the weekend, with a violent whirlwind tearing through a outdoor lodging area and a nearby hotel in Albufeira in southern Portugal on Saturday last week, claiming the life of an 85-year-old British woman and injuring two dozen and eight persons.

Extended Consequences across the European continent

The storm produced broader repercussions across western Europe. By drawing warm air from the subtropics, the system assisted in raising temperatures in France's south-west to 29.8C (85.6F), the country's highest recorded late autumn reading.

By the following Friday, this warm and humid air mass collided with a chilly atmospheric body across the northern regions of Europe, generating a rainfall belt running from western Ireland to the Russian Federation.

In the UK, this stalling band of rain delivered very high rainfall totals, resulting in significant waterlogging in the principality of Wales.

As the storm continues to weaken at the start of the week, the cold air mass will push south, providing the continent its initial glimpse of winter.

Simultaneous Occurrences in California, USA

California experienced an "atmospheric river" last week, causing torrential rain and strong winds that resulted in sudden inundations and mudslides in areas impacted by blazes previously in the year.

More than 50mm of rain was recorded in California's southern part on last Friday, with a further 50mm broadly over the state on Saturday last.

More than 100mm of rain was deposited on coastal areas of Southern CA in all, reaching 200mm overall in locations at higher elevations.

Such a weather system is a plume of tropical, saturated air coming from the tropics or subtropics.

Regions previously burned including Palisades and the town of Altadena suffered the worst of the flash flooding and mudslides, forcing residents to flee.

Across California, a man in his seventies died after his vehicle was swept off a flooded bridge, and a child of seven years and her father were swept into the sea by powerful waves on the the state's central shoreline.