Typhoon 6, named Chanmee, is bringing dangerous rain bands to northern Kyushu, prompting a Level 4 heavy-rain warning for Kagoshima Prefecture [1].

The storm's interaction with a stationary rain front has created a concentrated line of intense rainfall. This phenomenon, known as a line-shaped rain band, is overwhelming drainage systems and causing rapid inundation in residential areas.

In Satsumasendai City, residents reported that water levels rose within five to 10 minutes [3]. Local authorities deployed fire-department boats to assist with evacuations as roads became impassable and homes suffered floor-level flooding [1, 2].

"I have lived here for five years, but I have never seen the water come this high," said one local resident in Satsumasendai [3]. Other residents reported power outages lasting approximately two hours, leaving them unable to charge mobile phones [3].

The Japan Meteorological Agency is tracking the system, which recorded a center pressure of 980 hPa [2]. The typhoon has maximum sustained wind speeds of 25 m/s and maximum gusts of 35 m/s [2]. This event marks the first June typhoon to approach northern Kyushu in seven years, the first such occurrence since 2019 [5].

Forecasters expect the most severe impacts to occur over the weekend of June 26-27 [3]. While some reports suggest the system will move north and cause significant impacts on the Kanto region, other data limits the high-risk rain band forecast to the area between Kyushu and the Tokai region [1, 2].

Emergency services remain on high alert as the storm continues its northward trajectory. Residents in the affected prefectures are urged to follow evacuation orders and monitor water levels in small rivers, and streams [1, 3].

“I have lived here for five years, but I have never seen the water come this high”

The emergence of a line-shaped rain band significantly increases the risk of flash flooding compared to standard typhoon rainfall. Because these bands remain stationary over specific areas, they can dump immense volumes of water in short windows, bypassing traditional drainage capacity and necessitating rapid, boat-led evacuations in low-lying regions like Satsumasendai.