1,756
Recorded events
75
Counties affected
58
Direct deaths
$19.2B
Property damage
Puerto Rico flash flood history: 1,756 recorded events across 75 counties between 1996 and 2025.
Decade by decade
Puerto Rico flash flood history by decade
The 2020s are the busiest decade on record with 638 reported flash flood events across Puerto Rico. Earlier decades are thinner because systematic reporting for this hazard expanded over time, not because the weather was calmer.
County ranking
Counties with the most flash flood events in Puerto Rico
| Rank | County | Events | Deaths | Damage | Span |
|---|---|---|---|---|---|
| #1 | San Juan Municipio | 203 | 1 | $4.5M | 1997–2025 |
| #2 | Aguadilla Municipio | 89 | 0 | $767.3M | 1996–2025 |
| #3 | Adjuntas Municipio | 87 | 0 | $761.3M | 1997–2025 |
| #4 | Naguabo Municipio | 77 | 1 | $85K | 2008–2025 |
| #5 | Fajardo Municipio | 76 | 0 | $1.2M | 2009–2025 |
| #6 | Guaynabo Municipio | 67 | 0 | $1.6M | 2009–2025 |
| #7 | Aguada Municipio | 61 | 4 | $774.7M | 1996–2025 |
| #8 | Aibonito Municipio | 60 | 1 | $775.0M | 1996–2025 |
| #9 | Caguas Municipio | 57 | 0 | $752.7M | 1997–2025 |
| #10 | Carolina Municipio | 54 | 1 | $750.4M | 1996–2025 |
| #11 | Humacao Municipio | 53 | 3 | $5.2M | 1998–2025 |
| #12 | Ponce Municipio | 48 | 0 | $500.5M | 1998–2025 |
| #13 | Vega Alta Municipio | 47 | 1 | $750.6M | 2009–2025 |
| #14 | Bayamón Municipio | 46 | 0 | $750.9M | 1997–2025 |
| #15 | Aguas Buenas Municipio | 40 | 3 | $801.0M | 1996–2025 |
| #16 | Arecibo Municipio | 33 | 10 | $751.3M | 1996–2025 |
| #17 | San Sebastián Municipio | 33 | 2 | $154K | 2009–2025 |
| #18 | Río Grande Municipio | 31 | 0 | $31K | 2010–2025 |
| #19 | Toa Baja Municipio | 26 | 10 | $2.5B | 2010–2025 |
| #20 | Añasco Municipio | 25 | 5 | $800.1M | 1996–2025 |
| #21 | Yauco Municipio | 25 | 2 | $608K | 2010–2025 |
| #22 | Utuado Municipio | 25 | 4 | $750.7M | 2009–2025 |
| #23 | Patillas Municipio | 24 | 0 | $135K | 2011–2024 |
| #24 | Vega Baja Municipio | 23 | 0 | $122K | 2010–2025 |
| #25 | Mayagüez Municipio | 23 | 0 | $7.1M | 1998–2025 |
Significant events
Deadliest flash flood events in Puerto Rico
| Date | County | Scale | Deaths | Injuries |
|---|---|---|---|---|
| Sep 20, 2017 | Toa Baja Municipio | — | 9 | 0 |
| Nov 7, 2011 | Arecibo Municipio | — | 8 | 0 |
| Sep 20, 2017 | Añasco Municipio | — | 4 | 0 |
| Sep 20, 2017 | Utuado Municipio | — | 3 | 0 |
| May 28, 2010 | Barranquitas Municipio | — | 2 | 0 |
| May 6, 2001 | Aguas Buenas Municipio | — | 2 | 0 |
| Sep 15, 2012 | Guayanilla Municipio | — | 2 | 0 |
| Oct 22, 1998 | Humacao Municipio | — | 2 | 0 |
| Sep 20, 2017 | Aguada Municipio | — | 2 | 0 |
| Nov 10, 2022 | Juncos Municipio | — | 1 | 1 |