SAKIGAKE管理人 Introduction
The July 2018 Heavy Rains (West Japan Heavy Rains), which struck western Japan from July 6 to 8, 2018, became the worst flood disaster in postwar Japan, claiming 263 lives and leaving 8 missing. Centered on Hiroshima, Okayama, and Ehime Prefectures, it was an unprecedented wide-area disaster in which heavy rain special warnings were issued across 11 prefectures.
Yet the most serious problem that emerged from this disaster was not that “warnings failed to reach people.” Despite the fact that heavy rain special warnings and evacuation orders had been issued in advance across many affected areas, casualties from delayed evacuation continued to mount. The reality that “information had been put out. Yet people still did not move” — this is what has laid bare the fundamental challenge facing modern disaster prevention.
Why Did People “Not Evacuate”?
According to surveys conducted by the Cabinet Office, many of the victims of the West Japan Heavy Rains remained in their homes even after evacuation orders had been issued. Why do people fail to evacuate even when warnings have been issued?
Several psychological mechanisms are at work. One is normalcy bias — the assumption that “nothing major has ever happened here before” or “our area will be fine” leads people to underestimate danger. Another is an aversion to “false alarms.” People who have evacuated in the past only to find that nothing happened tend to think “it’s being overblown again.” Additionally, physical difficulties for the elderly and those moving at night, and social conformity pressure — “my neighbors aren’t moving, so I’ll wait too” — have been identified as factors that impede evacuation behavior.
What Mabi Town in Kurashiki City Revealed
The symbolic disaster site of the West Japan Heavy Rains was Mabi Town in Kurashiki City, Okayama Prefecture.The levee on the Oda River collapsed, inundating approximately 30% of the district. 51 people lost their lives, many of whom drowned on the first floor or in single-story homes, unable to evacuate to the second floor or higher.
Mabi Town was not a mountainous area — it was a residential neighborhood spread across a relatively gentle plain.The fact that an ordinary town, far from the image of “mountain areas near rivers being dangerous,” was suddenly submerged came as a shock to many. Evacuation orders had been issued, but the repeated testimony of “I never imagined the water would come this far” tells the true story of this disaster.
From “Issuing Information” to “Moving People to Act”
The West Japan Heavy Rains made it unmistakably clear that the challenge of disaster prevention has moved from the stage of “how to issue accurate information” to “how to actually get people to act.” No matter how precise the warning issued, lives cannot be protected if the people who receive it do not take action.
In response to this lesson, the Japan Meteorological Agency and the Ministry of Land, Infrastructure, Transport and Tourism reviewed their evacuation information framework, and in 2021 abolished the “evacuation advisory” category, consolidating it into “evacuation order” to sharpen the clarity of the message. However, changes in the system alone do not change human behavior. Whether a person can grasp a crisis as “something that concerns them personally” is shaped by the accumulation of drills, education, and culture over time.
Implications for Corporate Disaster Prevention and BCP
The reality that people “did not evacuate” during the West Japan Heavy Rains offers important insights for reviewing corporate disaster preparedness as well.
First, verify whether employees can “actually act” when it matters. Even if disaster prevention manuals and evacuation plans are in place, they are meaningless if employees cannot act on them when the moment arrives. The existence of a manual and employees being able to act on it are two separate things. It is essential to embed the right behaviors through regular, practical drills.
Second, systematically eliminate the assumption that “we’ll be fine.” As in the case of Mabi Town, it is not uncommon for places that have never suffered major damage before to suddenly sustain catastrophic harm. What is needed is a posture of evaluating risk based on the latest hazard maps and meteorological data, rather than on past damage records.
Third, build “getting ahead of decisions” into the system as an institution. When left to individual judgment, normalcy bias is likely to take hold. Stipulating rules in your BCP in advance — such as “when warning X is issued, action Y is automatically taken” — and minimizing on-the-spot decision-making improves the quality of an organization’s initial response.
Introducing a Related Solution
What the West Japan Heavy Rains demonstrated is the reality that “words alone — such as ‘heavy rain special warning’ — cannot help people vividly imagine a real crisis.” Rather than text-based information like “a heavy rain special warning has been issued,” what has the power to prompt action is real-time figures and changes — such as “right now, the ground around our facility has started to shift.” The following solution handled by SAKIGAKE JAPAN supports exactly that kind of “visualization of real-time risk.”
DIPPS Cloud | Portable Landslide Monitoring Stake System
“DIPPS Cloud” is a portable monitoring stake system that detects subtle ground movement in real time simply by inserting stakes into slopes or cliffs, and notifies the cloud wirelessly.
Multiple locations can be checked at a glance on the management screen, and when an anomaly is detected, the display changes from green to red and an instant email notification is sent to relevant parties. Rather than the abstract information that “a warning has been issued,” it delivers concrete data — “this is how much the ground at this specific location is moving right now” — which supports decision-makers in taking action. Combined with BCP rules such as “when readings exceed X, take action Y,” it enables objective criteria for decision-making that are not swayed by normalcy bias.
- Easy installation: Just insert the stake into the ground — no large-scale construction required
- Centralized cloud management: Monitor multiple locations on a single screen from a PC or smartphone
- Works even outside mobile coverage: Mountain areas covered via satellite communication and Starlink connectivity
- Approximately 2-year battery life: Continuous monitoring with minimal maintenance burden
“Information was out there. Yet people still did not move.” Taking this lesson to heart, please consider DIPPS Cloud as a system that delivers “information that moves people to act” in real time.
For details and inquiries, see below:
DIPPS Cloud Product Page
Conclusion
The West Japan Heavy Rains left society with a fundamental challenge at the cost of 263 lives: “information alone does not move people.” Warnings were issued. The hazard maps showed the danger. Yet people did not evacuate.
Changing this reality requires not only improvements in systems and technology, but also a culture of preparing as if it concerns you personally, and the organizational mechanisms to back it up. As professionals in corporate disaster prevention consulting and disaster risk management, SAKIGAKE JAPAN is fully committed to supporting your disaster preparedness and BCP development.