🔗 Share this article

Once again, Portugal and Spain find themselves recovering from widespread flooding after Tempest Claudia brought torrential downpours and powerful gusts the previous week.

The Storm's Formation and Trajectory

This weather system originated from a region of depressed atmospheric pressure that had beforehand driven early season cold and snowy conditions through the eastern regions of Canada and the American north-east in early November.

This storm tracked eastwards across the Atlantic in the middle of the second week of November before decelerating and halting to the north-west of the Iberian region, caught in the trough of an increasingly amplified air current.

Impact on Spain and Portugal

Galicia in north-west Spain was the first affected, with three to six inches of rain pouring down 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.

More downpours and stormy weather on Thursday last week led to floods to parts of Portugal where an elderly couple died in the capital Lisbon after floodwaters from the swollen Tagus invaded their residence as they slept.

Stormy conditions continued into the weekend, with a tornado devastating a outdoor lodging area and a close-by inn in Albufeira in southern Portugal on Saturday last week, claiming the life of an British woman aged 85 and injuring two dozen and eight persons.

Extended Consequences across Europe

The storm produced more extensive impacts across western Europe. By drawing warm air from the subtropical zones, the system contributed to thermometers climbing in France's south-west to 29.8C (85.6F), the country's highest recorded autumn temperature.

By Friday, this warm and humid air mass clashed with a frigid air system across the northern areas of the continent, forming a rainfall belt extending from Ireland's west to the Russian Federation.

In the United Kingdom, this halting system of rain produced exceptionally large precipitation amounts, resulting in significant waterlogging in the principality of Wales.

As the storm progressively weakens at the start of the week, the cold air mass will advance southward, providing the continent its premier experience of the winter season.

Simultaneous Occurrences in California

The US state of California underwent an "atmospheric river" last week, bringing intense precipitation and high-velocity gusts that resulted in sudden inundations and mudslides in zones scarred by blazes earlier this year.

More than 50mm of rain was recorded in southern California on last Friday, with a further 50mm widely across the state on the subsequent Saturday.

In excess of 100 millimetres of rain fell over coastal areas of the state's south in all, attaining a full 200 millimetres in areas of elevated terrain.

An atmospheric river is a concentrated stream of warm, moist air originating from the equatorial or near-equatorial zones.

Burn scar areas including Pacific Palisades and Altadena suffered the worst of the sudden floods and landslides, forcing residents to flee.

In other parts of the state, a man in his seventies died after his car was washed off a submerged bridge, and a seven-year-old girl and her father were pulled into the sea by powerful waves on the the state's central shoreline.