Weather tracker: More extreme rain in Japan and a tornado in France

Japan’s western coast has been battered by a series of extreme rainfall events, while western Europe has faced severe convective storms that produced hail and a tornado. The two episodes, driven by different atmospheric conditions, have left thousands displaced and caused widespread damage.

In Ishikawa and Toyama prefectures, heavy rain from moisture drawn in from the Sea of Japan fell on Thursday, triggering flash floods and mudslides. The town of Himi in Toyama recorded 361.5 mm of rain in a single 24‑hour period, roughly half the annual average rainfall for cities such as London and Paris. Rivers in the area burst their banks, flooding homes and damaging infrastructure. The Japan Meteorological Agency issued the highest‑level rain warning for both prefectures and issued landslide alerts, prompting the evacuation of hundreds of thousands of residents. Weather models forecast that an additional 200 mm could fall just to the south of the region as the moisture front moved in from the west.

Two days earlier, Typhoon Saudel had brushed the islands of Kagoshima and Okinawa in the southwest of the mainland, delivering winds of 100 mph (160 km/h) and heavy rainfall. In the Amami region, 230 mm of rain fell in one day. The storm was projected to head toward southeast China by week’s end, with markedly weaker winds. The increased frequency of such storms is linked to the ongoing El Niño, which alters the North Pacific High and allows tropical systems to track farther south before turning toward Japan. In El Niño years the ridge shifts northward, easing the passage of weather fronts and enabling storms to recur more often over the Japanese archipelago.

Meanwhile, a separate weather system over western Europe produced intense convective activity across the Alpine region. High‑pressure instability and strong vertical wind shear fed the development of large hail, winds, and a tornado. Spain, France and Italy were all struck, with hailstones up to 10 cm in diameter reported in Catalonia. In the village of Pomas in southwestern France, a tornado touched down, damaging buildings and uprooting trees. The storms were driven by a low‑pressure system skirting the western coast of Europe, which combined with the region’s convective instability to produce the severe weather.

Both the Japanese and European events illustrate how large‑scale climate patterns can influence regional weather extremes. While the El Niño phase has amplified rainfall in Japan, the European convective storms were a product of a low‑pressure trough and atmospheric instability. In both cases, the heavy precipitation and strong winds have resulted in flooding, mudslides, and structural damage, and have forced emergency services to respond to evacuations and rescue operations.

The incidents underscore the growing challenge of extreme weather events in an era of climate change. In Japan, authorities are monitoring the situation closely as additional rainfall is forecast, while European meteorological agencies have issued severe weather warnings for the Alpine and surrounding regions. The damage, both human and economic, remains significant as communities work to recover and rebuild.