HONOLULU, Aug. 21 (Reuters) — Tropical Storm Moke will dump 5 to 10 inches of rain on Hawaii’s Big Island starting late Saturday night, targeting ground already saturated by Hurricane Lala’s Aug. 16 landfall.
The collision of fresh rainfall with waterlogged terrain creates a high risk of catastrophic flash flooding and mudslides, according to the latest forecast models tracked on weather.com.
Moke is holding steady, drifting south of the island chain. That path spares Oahu and Maui from the worst, but keeps the Big Island’s windward slopes in the crosshairs for prolonged, heavy precipitation.
The State of Emergency: Lala’s Lingering Wounds
Lala’s August 16 punch flooded Kapiolani Boulevard in Honolulu, damaged infrastructure, and overwhelmed drainage systems.
Recovery crews are still clearing debris. Emergency shelters remain open. Power outages persist in scattered neighborhoods.
Soil moisture monitors operated by the USGS show the island’s upper soil layers at near-total saturation.
“We cannot absorb another significant rainfall event,” a Hawaii County Civil Defense spokesperson said Friday. “The ground is full. The next storm will run off or slide.”
Tropical Storm Moke: A Slow-Moving Menace
Moke’s forward speed has dropped to 7 mph. Slower movement means longer exposure.
Rainfall rates are forecast at 1 to 2 inches per hour in the heaviest bands.
The timeline runs from late Saturday night through early Tuesday.
Lala moved through quickly. Moke won’t.
Prolonged rain on saturated ground raises the landslide risk exponentially. For readers tracking “Tropical Storm Moke holding steady, expected to stay south of the islands,” the actionable detail is simple: the storm’s stability is bad news for the Big Island.
The Ticking Time Bomb: Why Saturated Ground is So Dangerous
Waterlogged soil loses cohesion. Slope failure follows.
Hawaii’s history is instructive.
In 2018, Hurricane Lane triggered landslides that severed communities on the Big Island’s east side. In 2021, the Kona floods killed two people and destroyed homes in a matter of hours.
The at-risk zones now include east-facing slopes above Hilo, areas near Volcano, and any recent burn scars that accelerate runoff.
| Location | Soil Moisture Status | Rainfall Forecast (in) | Primary Risk |
|---|---|---|---|
| Hilo (East) | Saturated | 8–10 | Flash flooding |
| Highway 11 (Volcano) | Saturated | 6–8 | Mudslides |
| Kona (West) | Moderately wet | 3–5 | Runoff/debris flows |
Impacts: Flooding, Mudslides, and Infrastructure Strain
Low-lying areas will flood. Streams and rivers will flash.
Highway 11 near Volcano is the primary mudslide risk. Isolated communities on the Hamakua coast could be cut off.
Storm drains are already at capacity. Power outages are likely. Water supply systems may be compromised.
The economic toll is immediate: tourism interruptions, school closures, and damage to coffee and macadamia farms.
Preparedness and Response: What Residents and Visitors Must Do
Sign up for Hawaii County Civil Defense alerts.
Monitor weather.com for real-time radar and updated warnings.
Identify safe zones. Pack emergency kits. Secure loose property.
Visitors should check hotel policies on weather-related cancellations and avoid flood-prone areas like Waipio Valley.
Community groups are distributing sandbags. Volunteer networks are mobilizing.
Forecast Outlook: What Happens After Moke?
Long-range models show Moke exiting by early Tuesday.
No additional disturbances are brewing in the Central Pacific.
The drying-out process will take at least a week. Long-term rebuilding will take months.
The Big Island’s infrastructure was not built for this frequency of extreme events. It will need to be rebuilt differently.
Conclusion
The window of danger is open from Saturday night through Tuesday.
Stay informed. Stay safe. Support local relief efforts.
Heed the warnings from weather.com and local authorities.
💡 Frequently Asked Questions (FAQ)
- Q: What is the main threat from Tropical Storm Moke?
- A: The main threat is heavy rainfall of 5-10 inches on already saturated ground, leading to catastrophic flash flooding and mudslides.
- Q: Which areas of Hawaii are most at risk?
- A: The Big Island’s windward slopes are in the crosshairs for prolonged heavy precipitation, while Oahu and Maui are spared the worst.
- Q: When will Tropical Storm Moke hit?
- A: The storm will begin late Saturday night and continue through early Tuesday, with rainfall rates of 1-2 inches per hour in the heaviest bands.
- Q: Why is the ground so dangerous?
- A: Hurricane Lala’s August 16 landfall saturated the soil, and USGS monitors show near-total saturation, meaning the ground cannot absorb more water.
Extended Reading
Additional reporting from Hawaii News Now, ABC News, and Maui Now indicates that Tropical Depression Two-C has slowed slightly as it continues toward Hawaii. Residents tracking the storm are advised that Moke’s trajectory, while south of the islands, maintains a persistent wet-weather pattern over the already saturated Big Island through the weekend.