The short version
- Hundreds of thousands of residents in Ishikawa and Toyama prefectures were evacuated after record-breaking rainfall caused rivers to burst their banks and trigger mudslides.
- Meteorologists attribute the increased frequency of storms approaching Japan this year to developing El Niño conditions, which alter atmospheric ridge patterns compared to La Niña years.
- Severe convective weather systems have simultaneously impacted western Europe, producing large hailstones in Spain and a significant tornado in southwestern France due to high instability and wind shear.
Japan is grappling with another wave of extreme weather events just weeks after an unprecedented deluge struck Chiba in mid-August. This latest surge of intense rainfall has targeted the western regions of the country, specifically Ishikawa and Toyama prefectures. Moisture drawn from the Sea of Japan delivered relentless precipitation on Thursday, overwhelming local infrastructure and prompting emergency responses across the affected areas.
The intensity of the storm in Himi, Toyama, was particularly severe, with 361.5 millimeters of rain recorded within a single twenty-four-hour period. To put this volume into perspective, that amount is roughly equivalent to half the average annual rainfall seen in major European capitals like London and Paris. The sheer weight of the water caused several rivers to overflow their banks, resulting in flash floods and mudslides that damaged or destroyed buildings in the region.
In response to the escalating danger, Japan’s Meteorological Agency issued its highest-level rain warnings for both Ishikawa and Toyama this week. These alerts were accompanied by specific landslide warnings, leading authorities to evacuate hundreds of thousands of people from their homes. Forecast models indicated that the situation could worsen, with an additional 200 millimeters of rain expected to fall just south of the currently hardest-hit areas as moisture continued to move in from the west.
This recent event follows closely on the heels of Typhoon Saudel, which passed through Kagoshima and Okinawa Island two days prior. The typhoon brought destructive winds reaching 100 miles per hour and extreme rainfall to these southwestern regions. In the Amami area alone, 230 millimeters of rain fell in a single day. The storm was projected to move into southeastern China by the end of the week, though its winds were expected to weaken significantly during that transition.
Climate experts suggest that the developing El Niño phenomenon may be a key driver behind the unusual frequency and intensity of storms approaching Japan this year. Unlike La Niña years, where the semi-permanent North Pacific High typically extends westward toward Japan, El Niño conditions tend to push this ridge northward. This shift allows weather fronts to penetrate more easily and enables tropical storms developing farther south to recurve toward the Japanese archipelago.
While warm ocean waters surrounding Japan naturally contribute to heightened typhoon activity during this time of year, the specific atmospheric changes associated with El Niño appear to be exacerbating the situation. The alteration in ridge patterns facilitates a more direct path for moisture and storm systems, explaining why so many extreme rain events have occurred in succession. This meteorological shift underscores the complex interplay between global climate patterns and regional weather extremes.
Simultaneously, western Europe has been battered by severe convective storms, particularly affecting the Alpine regions. These storms have produced a dangerous mix of intense rain, strong winds, large hail, and even tornadoes. Countries including Spain, France, and Italy have borne the brunt of this activity, with reports of hailstones up to 10 centimeters in diameter falling in Catalonia. A significant tornado also developed in the village of Pomas in southwestern France.
The severe weather in Europe stems from a combination of atmospheric factors, including a low-pressure system tracking along the western coast, high levels of convective instability, and strong vertical wind shear. These conditions created an environment ripe for violent storm development. As both Japan and Europe face these distinct but simultaneous weather crises, emergency services remain on high alert to manage the immediate dangers posed by flooding, landslides, and severe wind events.
Sources behind this briefing
Go to the original reporting
- The Guardian World↗Weather tracker: More extreme rain in Japan and a tornado in France
