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Once again, Portugal and Spain find themselves battling the aftermath of extensive flooding following Tempest Claudia brought torrential downpours and powerful gusts last week.

The Storm's Formation and Trajectory

The storm system developed from a region of depressed atmospheric pressure that had previously driven early season cold and snowy conditions through eastern parts of Canada and the north-eastern US during the beginning of the eleventh month.

Claudia tracked eastwards across the Atlantic over the second weekend of November before decelerating and halting to the northwestern area of the Iberian region, snared in a dip of an progressively more wavy jet stream.

Consequences for Spain and Portugal

The northwestern Spanish region of Galicia was the first affected, with three to six inches of rain pouring down along its Atlantic coast in just 24 hours up to the evening of Wednesday as a slow-moving band of rain crawled across western parts of the peninsula.

More downpours and stormy weather on the following Thursday brought flooding to parts of Portugal where a senior pair lost their lives in the capital Lisbon after floodwaters from the swollen Tagus invaded their residence as they slept.

Unsettled atmospheric states persisted into the weekend, with a twister devastating a camping ground and a nearby hotel in the town of Albufeira in Portugal's south on Saturday last week, claiming the life of an British woman aged 85 and injuring 28 people.

Broader Impacts across Europe

The storm produced wider effects across western Europe. By siphoning heated air from the subtropical zones, the system assisted in raising temperatures in south-west France to 29.8C (85.6F), the state's maximum ever November temperature.

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

In the Britain, this stationary front of rain brought very high rainfall totals, causing severe flooding in the Welsh region.

As this weather phenomenon progressively weakens early this week, the cold air mass will move towards the south, providing the continent its premier experience of the winter season.

Parallel Events in the state of California

The Golden State encountered an "atmospheric river" last week, delivering intense precipitation and high-velocity gusts that led to flash flooding and debris flows in regions impacted by blazes previously in the year.

Over two inches of rain poured down in California's southern part on last Friday, with a another 50 millimetres across extensive areas of California on Saturday.

Over four inches of rain accumulated over coastal areas of Southern CA in aggregate, attaining a full 200 millimetres in spots on high ground.

Such a weather system is a concentrated stream of hot, humid air coming from the tropical or subtropical regions.

Regions previously burned including Pacific Palisades and Altadena experienced the most severe the rapid inundations and earth movements, leading to evacuations.

Elsewhere in California, a 71-year-old man died after his car was washed off a inundated overpass, and a young girl aged seven and her father were pulled into the ocean by large waves on the California's Central Coast.