Hello, this is R2-TM.
I am deeply saddened by the recent damage caused by heavy rain in the Kyushu region. In recent years, the phrase linear precipitation band has entered the Japanese vocabulary to describe a phenomenon that has repeatedly caused devastating floods and landslides. Understanding this is no longer optional—it is essential knowledge for protecting our lives and communities.
In this article, I will provide a comprehensive guide: what linear precipitation bands are, why they form, examples from past disasters, how climate change is making them worse, and practical steps for preparedness. By the end, you will not only understand the science but also know exactly what actions to take when the next heavy rain event occurs.
What Is a Linear Precipitation Band?
A linear precipitation band (線状降水帯) refers to a continuous, stationary line of cumulonimbus clouds that repeatedly develops over the same area, producing torrential rainfall for many hours. Unlike normal thunderstorms that move quickly, these bands “park” themselves, creating catastrophic accumulations of rain in a short time.
The Japan Meteorological Agency (JMA) formally began using this term in 2021 for early warnings, after a series of disasters in the 2010s showed the urgent need for clearer communication. Today, JMA issues “Linear Precipitation Band Occurrence Information” when conditions indicate a band may persist and cause extreme rainfall.
Why They Are So Dangerous
- Massive Rainfall: 100–150mm of rain can fall within just a few hours, overwhelming rivers and drainage systems.
- Landslides: Soaked slopes lose stability, leading to catastrophic debris flows that engulf homes and roads.
- Infrastructure Collapse: Flooded transportation, blackouts, water outages, and disrupted logistics worsen the disaster’s impact.
👉 Related Reading: How to Prepare for Heavy Rain in Japan
Historical Disasters Caused by Linear Precipitation Bands
July 2018 Western Japan Torrential Rain
In 2018, western Japan experienced one of the most destructive disasters in decades. Over 200 lives were lost, thousands of homes destroyed, and transportation networks paralyzed. The rainfall exceeded records, with some areas receiving more than 1,000mm in less than a week. Linear precipitation bands were a key driver of the disaster.
August 2016 Northern Kyushu Torrential Rain
In 2016, northern Kyushu faced deadly floods and landslides. Dozens of fatalities occurred, and widespread power and water outages paralyzed local life. Recovery efforts took months, showing how localized but intense rainfall can devastate entire communities.
July 2017 Kyushu Northern Heavy Rain
In Fukuoka and Oita, linear precipitation bands triggered catastrophic landslides. Small villages were buried, and access roads were destroyed, isolating communities. Helicopter rescues were needed for stranded residents.
July 2020 Kumamoto Floods
The Kuma River overflowed after a linear precipitation band brought record-breaking rainfall. Elderly care homes were submerged, leading to tragic casualties among vulnerable residents. This event highlighted the urgent need for early evacuation of the elderly and disabled.
Overseas Examples
While the term is Japanese, similar phenomena occur worldwide. In the United States, “training thunderstorms” can cause flash floods. In Europe, stalled storm systems have caused severe flooding in Germany and Belgium (2021). Climate change is increasing the intensity of such events globally.
Climate Change and the Future of Heavy Rain
Why are linear precipitation bands becoming more frequent? Climate scientists point to global warming. A warmer atmosphere holds more water vapor. For every 1°C increase, air can hold 7% more moisture. In Japan, rising sea surface temperatures also fuel convection, feeding heavy rainstorms.
The Intergovernmental Panel on Climate Change (IPCC) warns that extreme precipitation events are expected to increase in both frequency and intensity worldwide. Japan, with its mountainous terrain and dense rivers, is especially vulnerable.
👉 Related Reading: Climate Change and Japan’s Increasing Weather Risks
Preparedness and Countermeasures
Knowledge is only useful if it translates into action. Here are concrete steps to take before, during, and after heavy rain events caused by linear precipitation bands.
1. Know Your Risk
- Check your city’s hazard maps for flood and landslide risk zones.
- Understand the evacuation alert levels (Level 3: elderly should evacuate, Level 4: everyone should evacuate, Level 5: disaster already occurring).
2. Household Preparedness
- Emergency Kit: Water (3L per person per day), food for 3 days, flashlight, portable charger, first-aid kit, radio, masks, and gloves.
- For Families with Children: Diapers, baby food, formula, and comfort items.
- For Elderly or Disabled Members: Necessary medicines, mobility aids, and early evacuation planning.
- For Pet Owners: Pet food, leashes, carriers, and vaccination records.
3. Safe Actions During an Event
- Evacuate early—do not wait until nightfall or water rises.
- Move to higher floors if evacuation is impossible.
- Stay tuned to official channels: TV, radio, smartphone alerts.
- Avoid rivers, bridges, and underpasses during rainfall.
4. After the Rain
- Do not re-enter flooded homes until authorities declare it safe.
- Beware of secondary landslides and weakened ground.
- Document damages for insurance claims with photos and receipts.
👉 Related Reading: Typhoon Preparedness Guide
Practical Items for Emergencies
- Waterproof bag for valuables
- Flashlight & spare batteries
- Non-perishable food and bottled water
- Portable power bank
- Blankets and clothing
- Battery-powered radio
- Masks, gloves, and sanitizer
Conclusion
Linear precipitation bands are among the deadliest weather patterns in modern Japan. By studying past tragedies, understanding their causes, and implementing preparedness at both individual and community levels, we can reduce risks. Remember: preparedness is not an overreaction—it is a life-saving habit.
Today’s Birth Flower: Mint (Precious Moments)
Thank you for reading. Stay safe and keep disaster preparedness a part of your everyday life.
