In mid-March 2026, back-to-back Kona low systems dropped more than 60 inches of rain across six Hawaiian islands, triggering the most destructive flooding the state had seen in over two decades. By the time the second storm passed, early damage estimates had already crossed $1 billion in combined public and private losses. This article walks through what a Kona low actually is, how the two storms unfolded, which communities were hit hardest, and what travelers should know about visiting Hawaii during Kona low season.
Two back-to-back Kona low systems within ten days — a pattern National Weather Service meteorologists consider highly unusual — dropped more than 60 inches of rain across six Hawaiian islands, causing over $1 billion in estimated damages.
A Kona low is a slow-moving, upper-level low-pressure system that pulls moist air from the south and southwest, reversing Hawaii’s normal trade-wind pattern and flooding typically dry leeward areas. The March 2026 event was exceptionally destructive because two of these systems arrived in rapid succession, saturating soils and overwhelming drainage infrastructure before the first storm’s floodwaters had receded. If you’re traveling to Hawaii between October and April, understanding Kona low risk — and knowing which areas are most vulnerable — is key to planning a safe trip.
| Tradition / System | What It Is | Where It Affects | Key Safety Note |
|---|---|---|---|
| First Kona Low March 9–15, 2026 | Upper-level low stalled northwest of Hawaii, pulling deep tropical moisture over the islands for nearly a week | All major islands; 5–10 inches widespread, 30+ inches in upslope terrain; Honolulu broke a 24-hour rainfall record that had stood for 75 years | Leeward areas usually dry — expect flash flooding when trade winds reverse |
| Second Kona Low March 19–22, 2026 | Another low arrived just days after the first, dropping heavy rain onto already saturated watersheds and elevated stream flows | Compounded flooding across Oahu, Maui, and Hawaii Island; 22.51 inches at Kaala on Oahu alone | Second storms on wet ground produce faster runoff — evacuation zones expand |
| Wahiawa Dam Threat Oahu, March 2026 | 120-year-old reservoir rose 6 feet in 24 hours, cresting at 85 feet, prompting evacuation orders for 5,000+ residents downstream | North of Honolulu; Wahiawa Dam flood inundation zones were analyzed in real time by response agencies | Dam safety is a serious concern during Kona lows — always heed evacuation orders promptly |
What Is a Kona Low — and Why Does It Flood Hawaii?
Under normal conditions, Hawaii’s trade winds blow steadily from the east, dumping rain on windward slopes while leeward sides stay comparatively dry. A Kona low flips that pattern — “kona” is Polynesian for “leeward.” These low-pressure systems form west to northwest of the islands during the cool season, typically October through April, and tap into subtropical moisture, driving cooler, moisture-rich winds from the south to southwest. When a Kona low stalls near the islands, as the March 2026 system did for nearly five days, it can produce catastrophic rainfall totals in areas that rarely see heavy rain. On average, one to two Kona storms affect Hawaii each season — having two hit within the same week is extremely rare, according to National Weather Service meteorologists.
Peak wind gusts recorded at higher elevations during the first Kona low, according to weather station data.
Because the Kona low draws moisture from the south and southwest, areas that usually escape the heaviest rain — leeward coasts, central plains, and the North Shore of Oahu — become the front line. The March 2026 event was a textbook example: the first storm stalled northwest of the islands during roughly March 9 to 15, repeatedly pulling deep tropical moisture into the state and producing multiple waves of torrential rainfall and embedded thunderstorms across all major islands, alongside damaging south to southwesterly winds. Just days later, a second Kona low arrived around March 19, bringing another round of heavy rain onto already saturated watersheds and elevated stream flows. This sequencing amplified runoff response and prolonged flooding impacts, since the second wave occurred before soils, channels, and infrastructure systems had time to recover from the initial event.
First Kona Low — March 9–15, 2026
The first storm set the stage with widespread rainfall totals of 5 to 10 inches across most islands, with swaths of 15 to 25 inches over parts of Maui and Hawaii Island and localized 30+ inch totals in upslope terrain. Honolulu broke a 24-hour rainfall record that had stood for 75 years. Wind gusts of 60–75 mph were widespread, with some locations recording 100+ mph and higher elevations hitting 135 mph. At the storm’s peak, more than 130,000 Hawaiian Electric customers were without power, and by the afternoon of Sunday, March 22, more than 32,000 were still without electricity as repair crews worked through restoration. Emergency services reported that more than 350 people were pulled from hazardous conditions during the peak response period.
Damage to roads, bridges, and drainage infrastructure was severe. The Hawaii Department of Transportation preliminarily estimated storm damage at roughly $23 million statewide, about $7 million on Maui alone. Roads collapsed, bridges failed, and Lahaina — still recovering from the 2023 wildfires — flooded again as 1960s-era infrastructure designed for 100-year storms was overwhelmed twice in three weeks.
If you’re on a leeward coast during a Kona low, don’t assume you’re safe from flooding just because the weather is typically dry there. The reversal of normal wind patterns means the areas that are usually sheltered become the most vulnerable. Check local emergency dashboards for real-time alerts.
Second Kona Low — March 19–22, 2026
Just days after the first storm’s floodwaters began to recede, a second Kona low arrived. The compounding effect was devastating. The second storm dropped 22.51 inches at Kaala on Oahu alone. Watersheds that were already saturated couldn’t absorb additional rainfall, so runoff was immediate and severe. The 120-year-old Wahiawa Dam in central Oahu drew focused attention as reservoir levels rose 6 feet in 24 hours, cresting at 85 feet. Evacuation orders were issued for approximately 5,000 residents in downstream areas. The Pacific Disaster Center’s DisasterAWARE platform was used to analyze dam flood inundation zones and communicate downstream evacuation zones in real time, helping response agencies coordinate evacuations across multiple islands simultaneously.
NASA satellite imagery captured the transformation. Landsat images from January 25 show green farmland and clear coastal waters between Mokuleia and Waialua. By March 14, after the first Kona low, the same area was visibly swamped — floodwaters pooled across neighborhoods and farmland, while massive plumes of suspended sediment discolored the waters around Kaiaka Bay. The distinctive red-brown color came from Hawaii’s volcanic Hilo soils, rich in iron and aluminum oxide. The second storm only deepened the flooding.
Infrastructure, Agriculture, and the Road to Recovery
The full extent of the damage took weeks to assess. By early April, the state had confirmed that at least 260 homes — or 17% of all homes damaged during the record rainfall and flooding — were deemed uninhabitable without major repairs based on reports verified by the county. Another 445 properties suffered non-structural damage that required lower levels of repair and were habitable, while 443 residents reported damage at the nuisance or cosmetic level. The city of Honolulu asked residents to report storm-related damage starting March 25, with the data compiled to unlock potential federal assistance from FEMA and other programs. The deadline for federal applications was June 14.
Agricultural losses were significant. The state estimated $23 million in agricultural economic losses, including flooded fields, downed trees, damaged farm structures, and operational disruptions. Dairy farms, taro patches, and nurseries across the islands were affected. The North Shore’s agricultural heartland, already dealing with the aftermath of the first storm, took another hit from the second.
Damaged across the state, along with 9 seaports and an estimated $129.7 million in highway damage, according to PDC’s preliminary assessment.
Recovery efforts were coordinated across multiple agencies. The Pacific Disaster Center staffed 20 Emergency Operations Center shifts statewide, with 30% of PDC staff activated for response. They delivered 40+ advanced analytical products, including new radar data for Hawaii, updated flood zone layers, and updated dam flood inundation data. The DisasterAWARE Common Operating Picture enabled county and state agencies across islands to contribute and view Situation Reports simultaneously, which was especially critical because Hawaii’s primary Molokai weather radar was offline for both Kona low systems.
If you’re visiting Hawaii during Kona low season, download the PDC Disaster Alert mobile app — downloads increased 100% during the March storms. It provides real-time hazard information, including flood zones, landslide risks, and evacuation notices, all in one place.
Staying Safe During Kona Low Season in Hawaii
Kona low season runs roughly from October through April, with the highest risk typically in late winter and early spring. Understanding the risks and preparing accordingly can make the difference between a disrupted trip and a dangerous one.
Know Your Vulnerability
Leeward areas — the North Shore of Oahu, leeward Maui, the Kona coast of Hawaii Island — are at highest risk during a Kona low because they’re not designed for heavy rainfall. Drainage infrastructure in these areas was built for the dry conditions they normally experience. When a Kona low stalls, these areas flood quickly. Check the flood zone maps for your accommodation before you book.
Flood Insurance Coverage Is Low
Only about 4.2% of properties in Hawaii carry flood insurance, leaving more than 400,000 properties statewide without coverage. Hawaii’s Community Rating System classes — Hawaii and Maui Counties at Class 7, Honolulu City and County and Kauai County at Class 8 — mean limited flood insurance premium discounts. If you’re renting a vacation home or staying in a ground-floor unit in a leeward area during Kona low season, consider whether your travel insurance covers flood-related cancellations or disruptions.
Monitor Alerts and Heed Evacuations
During the March 2026 event, the city of Honolulu urged residents to report damage through an online portal, and the data was used to unlock federal assistance. For travelers, the key takeaway is to monitor local emergency management agencies and heed evacuation orders immediately. The 5,000 residents evacuated from the Wahiawa Dam downstream zone had limited time to leave — the reservoir rose 6 feet in 24 hours. If you’re in an area under an evacuation order, don’t wait to see how bad it gets.
Climate change is increasing the intensity of Hawaii’s Kona low storms. Warmer air can support heavier downpours, and rising sea levels worsen coastal drainage and backwater conditions, making it harder for stormwater systems and streams to discharge during high-tide periods. The March 2026 event is a reminder that Hawaii’s flood risk sits at the intersection of extreme rainfall, sea level rise, and aging infrastructure.
Before You Go: Kona Low and Hawaii Flooding Questions Answered
What exactly is a Kona low?
A Kona low is a slow-moving, upper-level low-pressure system that forms west to northwest of Hawaii during the cool season. “Kona” means “leeward” in Polynesian, and these storms draw moisture from the south and southwest, reversing the normal trade-wind pattern. They can produce extreme rainfall on typically dry leeward coasts.
How common are Kona lows?
On average, one to two Kona storms affect Hawaii each season. Having two hit within the same week — as happened in March 2026 — is extremely rare, according to the National Weather Service. The dual-system pattern amplified the damage because the second storm arrived before soils and infrastructure had recovered.
Is it safe to travel to Hawaii during Kona low season?
Yes, but with precautions. Monitor weather forecasts, choose accommodations in areas less prone to flash flooding, and have a flexible itinerary. Avoid low-lying leeward coastal areas during active Kona low events. The PDC Disaster Alert mobile app provides real-time hazard information.
Which areas are most vulnerable during a Kona low?
Leeward areas that are normally dry: the North Shore of Oahu (Haleiwa, Waialua, Mokulēʻia), leeward Maui, the Kona coast of Hawaii Island, and central plains where rainfall gets channeled by terrain. Shallow soils and sparse vegetation on leeward slopes increase landslide risk.
What should I do if I’m in Hawaii during a Kona low warning?
Stay indoors, avoid driving through floodwaters, monitor local emergency alerts, and evacuate immediately if ordered. Don’t assume you can outdrive a flash flood — water rises faster than most people expect. If you’re in a low-lying area, move to higher ground before conditions worsen.
- Kona lows are a normal part of Hawaii’s cool season, but the March 2026 dual-system event was historically rare and destructive.
- Leeward areas — North Shore Oahu, leeward Maui, Kona coast — are most vulnerable because they’re not designed for heavy rainfall.
- Only 4.2% of Hawaii properties carry flood insurance; check your travel coverage for flood-related disruptions.
- Monitor the PDC Disaster Alert app and local emergency management for real-time updates during active Kona low events.
- If you’re in an evacuation zone, leave immediately — the Wahiawa Dam situation showed how fast conditions can change.
A New Understanding of Hawaii’s Weather
The March 2026 Kona low event was a reminder that Hawaii’s weather is not always the gentle trade-wind paradise of postcards. The back-to-back storms exposed vulnerabilities in infrastructure, housing, and emergency preparedness that will take years to fully address. But they also demonstrated the power of real-time data sharing and coordinated response across agencies and islands. For travelers, the takeaway isn’t to avoid Hawaii during the cool season — it’s to come informed, stay flexible, and respect the island weather patterns that have shaped Hawaiian life for centuries. The same forces that bring the rain also bring the green that makes the islands so beautiful. If you’re curious about how traditional Hawaiian knowledge interprets these seasonal shifts, the ancient Hawaiian tide calendar offers a deeper understanding of the natural rhythms that govern island life.
References
Guy Carpenter. “Post-Event Report: Hawaii Flood March 2026.” Guy Carpenter, April 2026. ↗
Pacific Disaster Center. “Hawaii Flood Response Case Study 2026.” PDC, 2026. ↗
Mappr. “Kona Storms Flood Oahu Hawaii 2026.” Mappr, 2026. ↗
Civil Beat. “Kona Low Storm Damage: It Wasn’t Just the North Shore That Was Hit Hard.” Civil Beat, May 2026. ↗
ENR. “Maui Kona Storm Damage: Roads Collapse, Bridges Fail, Lahaina Floods Again.” ENR, March 2026. ↗
For more context on Hawaii’s seasonal patterns and how they shape travel, check out our guide to family-friendly adventures in Hawaii and our breakdown of the best snorkeling spots — both excellent ways to enjoy the islands when the weather is clear. If you’re planning a trip during the cooler months, it’s also worth understanding the Hawaiian language and cultural connections that make the islands so special.
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