Akita's Koyoshi River flood warning downgraded to advisory after overnight overflow
In short
The Japan Meteorological Agency switched the Level 5 flood special warning for the Koyoshi River in Yurihonjo, Akita Prefecture, to a Level 2 flood advisory at 02:20 on 22 October. The river overflowed on the evening of 21 October after heavy rain, and the advisory was lifted at 06:20. The city said no harm to people or buildings had been confirmed so far.
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The Japan Meteorological Agency switched the Level 5 flood special warning for the Koyoshi River, which flows through Yurihonjo in Akita Prefecture, to a Level 2 flood advisory at 02:20 on 22 October. It said the water level had fallen sufficiently. Yurihonjo city also lifted its Level 5 emergency safety order, which asks residents to take action to protect their lives. [ 1 , 2 , 6 , 7 ]
Rain fell continuously in Akita on 21 October as warm, moist air flowed toward a low-pressure system and a front, according to TBS NEWS DIG. NHK described a rapidly developing low and front that brought record heavy rain. The agency and the Ministry of Land, Infrastructure, Transport and Tourism issued the Level 5 flood special warning at 19:45, citing a possible overflow. Flooding was then confirmed, and the tributary Ishizawa River also flooded. [ 1 , 2 , 3 ]
Nippon TV reported that 24-hour analysed rainfall in Yurihonjo reached 290 mm by 19:30 on 21 October. About 45 minutes later the Akita River and National Highway Office and the Akita Local Meteorological Observatory announced an overtopping flood on the Koyoshi River; Nippon TV placed it in the Moriko district. Separately, Kyodo, carried by Nikkei, reported 129 mm in the 24 hours to the afternoon of 21 October at Sasago in Yurihonjo, the most for October at that point. [ 6 , 7 , 9 ]
On the evening of 21 October the city issued a Level 5 emergency safety order to 448 households (1,204 people) in the Kubota, Nishitakizawa and Ishizawa districts, and lifted it all early on 22 October. Two shelters opened in the city were closed; TBS NEWS DIG said that for a time 5 households (15 people) had taken shelter there. [ 8 , 9 , 10 ]
The flood advisory was lifted at 06:20 on 22 October, Nippon TV reported. It said the river level was calmer than on the night of 21 October but that people going out still needed to check their safety. The city said no harm to people or buildings had been confirmed so far but that flood damage might come to light. As of 09:00, TBS NEWS DIG reported farmland flooded over a wide area and no information on human casualties. [ 9 , 10 ]
Funabashi Yayoi (舟橋弥生), head of the River Environment Division at the Ministry of Land, Infrastructure, Transport and Tourism, said: "Stay away from rivers, irrigation channels and low-lying areas. Do not travel by car in areas at risk of flooding. Do not enter flooded roads." Earlier, TBS NEWS DIG said the Koyoshi River was expected to stay high for some time. [ 1 , 2 ]
Why it matters
Heavy rain from a low-pressure system and front caused flooding in Yurihonjo, and evacuation instructions covered 448 households. The city said damage from flooding could still come to light, and officials urged people to keep checking for safety when going out.
Key facts
- The Japan Meteorological Agency switched the Level 5 flood special warning for the Koyoshi River in Yurihonjo, Akita Prefecture, to a Level 2 flood advisory at 02:20 on 22 October. [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]
- The agency and the Ministry of Land, Infrastructure, Transport and Tourism issued the Level 5 warning at 19:45 on 21 October; flooding was then confirmed, and the tributary Ishizawa River also flooded. [ 1 , 2 ]
- The Level 2 advisory was lifted at 06:20 on 22 October. [ 9 ]
- Yurihonjo city issued a Level 5 emergency safety order to 448 households (1,204 people) in the Kubota, Nishitakizawa and Ishizawa districts and lifted it all early on 22 October. [ 9 ]
- Two shelters opened in the city were closed; for a time 5 households (15 people) had sheltered there. [ 8 , 10 ]
- As of 09:00 on 22 October there was no information on human casualties, and farmland was flooded over a wide area. [ 10 ]
- At Sasago in Yurihonjo, 129 mm of rain fell in the 24 hours to the afternoon of 21 October, the most for October at that point. [ 6 , 7 ]
Confirmed by several sources
- The Level 5 flood special warning for the Koyoshi River was switched to a Level 2 flood advisory at 02:20 on 22 October. [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]
- The Koyoshi River overflowed on 21 October, and the Ishizawa River, a tributary, also flooded. [ 1 , 2 , 9 ]
- The city lifted the Level 5 emergency safety order after the water level fell. [ 6 , 7 , 9 ]
Still unclear
- The extent of flood damage. The city said no harm to people or buildings had been confirmed so far but that damage from flooding could still become known; farmland was reported flooded over a wide area.
- Rainfall figures differ between outlets. Two outlets cite 129 mm in 24 hours at Sasago, while another cites 290 mm of 24-hour analysed rainfall for Yurihonjo to 19:30 on 21 October; the documents do not say how the two measures relate.
- Shelters opened in Yurihonjo were closed. Reported by a single source so far
What local media are saying
Timeline, local time
- On 21 October, 24-hour analysed rainfall in Yurihonjo reached 290 mm. [ 9 ]
- The Japan Meteorological Agency and the MLIT issued the Level 5 flood special warning for the Koyoshi River. [ 1 , 2 ]
- About 45 minutes after the 19:30 rainfall reading, the Akita River and National Highway Office and the Akita Local Meteorological Observatory announced an overtopping flood on the Koyoshi River. [ 9 ]
- On 22 October the Level 5 warning was switched to a Level 2 flood advisory. [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]
- The flood advisory was lifted. [ 9 ]
- No information on human casualties; farmland flooded over a wide area. [ 10 ]