Rainwater burst from a manhole in Ikeda-cho, Hokkaido, on Monday after a brief but intense downpour [1], [2].
The incident highlights the volatility of "guerrilla" rain showers, localized, heavy precipitation, that can overwhelm urban drainage systems in minutes. Such events create sudden, high-pressure surges in underground infrastructure, posing risks to pedestrians and motorists.
The eruption occurred around 3 p.m. local time on June 29, 2026 [2], [3]. The water spewed from the manhole with a force described as being like an explosion [2], [3]. This phenomenon was triggered by a short-lived but severe rain shower generated by a double typhoon system impacting Japan [1], [2].
A cameraman who recorded the event said the heavy rain lasted for only approximately 10 minutes [2]. Despite the short duration, the volume of water was sufficient to create the pressure necessary to force the manhole cover to erupt [2], [3].
While the Hokkaido incident involved a localized burst, the double typhoon system has caused widespread disruptions across the region [1]. Other areas are facing severe weather warnings; for example, a Level 4 landslide warning was issued for Toshima Village [2].
Local authorities continue to monitor the effects of the double typhoon as additional storm systems develop in the region [1]. The sudden nature of these guerrilla rains makes them particularly difficult to predict, often leaving residents with little time to seek shelter or clear drainage paths.
“Rainwater burst from a manhole like an explosion during a short, intense downpour.”
The eruption in Ikeda-cho demonstrates the increasing risk of 'guerrilla rain' events, where extreme precipitation occurs over a very small area in a short window. As these events intensify due to complex weather patterns like double typhoons, traditional sewage and drainage infrastructure may struggle to handle the rapid pressure spikes, potentially leading to more frequent urban flooding and infrastructure failures.
