⚠ Wahiawa Dam Threat (March 20)
Reservoir peaked 85.29 ft (flood stage 84 ft). Imminent failure declared 08:22 HST. ~5,500 evacuated. Dam receded without failure.
Inundation Depth (click to toggle)
Deep ≥ 6 ft
Moderate 3–6 ft
Shallow 1–3 ft
Trace < 1 ft
Event Impact ▶
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Buildings with inundation damage
Oahu, Hawaii — March 2026
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Estimated ground-up structural loss
HAZUS DDC • NSI structure values
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Mean damage index (affected structures)
Governor estimate: $1.0B (all damage types)
USGS Gauge Peaks
Wahiawa Reservoir
85.29 ft ⚠
Kaukonahua blw Res.
20.87 ft
Kaukonahua at Waialua
30.26 ft
Social Media Signal (Google Trends • Reddit)
"evacuation" — peak interest (HI)
100 / 100
"oahu evacuation" — related search
100 / 100
"wahiawa dam" — related search
42 / 100
"flood damage" — peak interest (HI)
6 / 100
r/Hawaii • 259 upvotes
Didn't wanna sleep anyway
r/Hawaii • 133 upvotes
'Catastrophic flash flooding' in Waialua & Haleiwa prompts evacuation
r/Hawaii • 120 upvotes
Military (Coast Guard) helping evacuation
r/Hawaii • 87 upvotes
Weather update: Minor flooding impacts possible — NWS Honolulu advisory
NWS Warnings & Advisories
Flash Flood Warnings (FF)
1
Flood Warnings (FL)
8
Flood Advisories (FA)
10
Total NWS products
19
Event Summary
Successive Kona lows (Mar 10–16 & Mar 19–20) dropped 19+ inches on Schofield/Wheeler area. Wahiawa Dam peaked 85.29 ft — above flood stage (84 ft). Imminent failure declared 08:22 HST Mar 20. ~5,500 evacuated from Haleiwa, Waialua, Mokuleia. 138,000 under life-threatening flash flood emergency.
Governor Estimate
Gov. Josh Green: $1.0B total damage — includes structures, crops, roads, infrastructure. Structure-only insured losses not yet published.
What-If Scenarios (Hummingbird Research)
⚠ Dam Failure: Wahiawa Dam
~$2.5–3.5B estimated (rough)
Corridor flood surface: 80 ft NAVD88 (vs 50 ft actual). Full 9,200 ac-ft release, 12 mi inundation corridor to Haleiwa. Est. 3–4× more corridor buildings at full submersion depths. Does not include BI, roads, or crop losses.
Flood Surface +5 ft (higher stage)
~$960M–$1.0B estimated (rough)
Corridor: 55 ft NAVD88 • Haleiwa coastal: 25 ft • Waialua: 50 ft. Est. 10–15% more structures at corridor margins vs base case ($879.8M).
Flood Surface −5 ft (lower stage)
~$710–$750M estimated (rough)
Corridor: 45 ft NAVD88 • Haleiwa coastal: 15 ft • Waialua: 40 ft. Est. 15–20% fewer structures inundated vs base case. Haleiwa coastal strip largely excluded.
Rough estimates based on corridor building density and elevation exposure. Full model runs are Phase 2.
Loading flood damage data…