Japan Meteorological Agency Latest Flood Risk Map “Lowest” River Flooded Niigata Oct 18 19:12
About the Jodo River in Nagaoka City, Niigata Prefecture, where many houses were damaged by water due to the impact of Typhoon No. 19, "Distribution of Flood Warning Risk" that the Meteorological Agency would notify the river water level rise at the time of the damage Then it turned out that it was the lowest level. The Niigata Local Meteorological Observatory says, “There is a problem that the current JMA technology cannot express enough, and we are striving to improve it.”
“The flood warning risk distribution” was started by the Japan Meteorological Agency in response to the flooding of small and medium-sized rivers throughout the country.
About 20,000 rivers nationwide, such as rivers without water level gauges, the risk of flood damage from floods is shown on a map in five different colors in real time and is used as reference information for residents to evacuate.
However, at 8:00 am on the 13th, at the Jodo River in Nagaoka City, where 125 houses in the basin caused water damage due to the impact of Typhoon No. 19, this “Risk Distribution” It turned out that it was the lowest level as "careful about future information".
The cause of the overflow of the Jodo River seems to be due to a phenomenon called “backwater” in which the water level of the mainstream Shinano River rises and the water level of the tributary is blocked and the water level rises. It was difficult to convey evacuation information to the residents.
“The risk is calculated based on the amount of rainfall in the surrounding area, and the rise in water level due to“ backwater ”cannot be reflected,” said the Kaneko Law History Observation Forecast Manager at Niigata Local Meteorological Observatory.
On top of that, he says, “There is a problem that the current JMA technology cannot express enough, and we are working hard to improve it.”