The Japan Meteorological Agency issued a Level 4 flood-danger warning for the Katsuura River in Tokushima Prefecture on June 3, 2026 [1].
The alert signals a critical risk of river flooding, necessitating immediate action from residents in affected areas to ensure public safety.
Rising water levels prompted the high-alert status [1]. According to the Tokushima Local Meteorological Observatory, water levels at the Yokose standard observation station in Katsuura Town are expected to remain above the evacuation judgment level [2].
While most primary reports cite a Level 4 flood-danger warning [1], some reports from Oita Press described the situation as a Level 3 equivalent [3]. The Level 4 designation is the higher-trust tier warning used for imminent danger of flooding.
Weather officials linked the volatility to the movement of Typhoon 6. The Japan Meteorological Agency said the storm is expected to make its closest approach to the Kinki region from early morning to the morning of June 3 [4].
Some reports indicated the Level 4 warning was specifically associated with a line-rain-band created by the typhoon [4]. This atmospheric phenomenon often leads to concentrated, heavy rainfall over a specific area, which rapidly increases the volume of river systems like the Katsuura River.
Local authorities have urged residents to monitor water levels, and follow evacuation orders as the typhoon moves through the region.
“The Japan Meteorological Agency issued a Level 4 flood-danger warning for the Katsuura River”
The issuance of a Level 4 warning indicates that the risk of flooding has moved beyond a general threat to an imminent danger, requiring residents to evacuate to safety. The intersection of Typhoon 6 and the formation of a line-rain-band creates a high-risk scenario for flash flooding and river breaches in Tokushima Prefecture.
