PlainHazard

Volcanic Ash

NOAA Storm Events type · 70 records since 1997 · 6 states and territories

The National Weather Service defines volcanic ash as: "Fine particles of mineral matter from a volcanic eruption which can be dispersed long distances by winds aloft, resulting in fatalities, injuries, damage, or a disruption of transportation and/or commerce." NOAA's Storm Events Database holds 70 volcanic ash records from 1997 through June 30, 2026, the most in Puerto Rico (42).

How the National Weather Service files volcanic ash

Fine particles of mineral matter from a volcanic eruption which can be dispersed long distances by winds aloft, resulting in fatalities, injuries, damage, or a disruption of transportation and/or commerce. Beginning Time - When volcanic ash began to cause disruption to transportation, commerce, fatality, injury, or damage.
National Weather Service Instruction 10-1605, Storm Data Preparation (July 26, 2021), Appendix A, entry 51

Source: National Weather Service Instruction 10-1605. Read the instruction (PDF).

Volcanic Ash, 1997 to 2026

Records per year (2026 to June 30, 2026).

  • recorded, no damage figure
  • under $10 million
  • $10 million or more
  • $100 million or more
  • $1 billion or more, or 100 deaths
  • $10 billion or more, or 1,000 deaths
  • a year's colour: its recorded damage or deaths
  • a year with a death
Records
701997 to June 30, 2026
Deaths
00 injuries
Damage, 2025 dollars
$833Kas filed (scale steps before 1993)
Counties with a record
83of 3,266

Source: NOAA NCEI Storm Events Database, records through June 30, 2026. Search the record at NCEI.

Where do volcanic ash records happen?

States

  1. Puerto Rico 42
  2. U.S. Virgin Islands 14
  3. Northern Mariana Islands 5
  4. Guam 4
  5. Alaska 4
  6. Washington 1

Counties

  1. St. Croix Island, VI 8
  2. Vieques Municipio, PR 5
  3. Río Grande Municipio, PR 5
  4. Naguabo Municipio, PR 5
  5. Luquillo Municipio, PR 5
  6. Humacao Municipio, PR 5
  7. Fajardo Municipio, PR 5
  8. Culebra Municipio, PR 5
  9. Ceiba Municipio, PR 5
  10. Canóvanas Municipio, PR 5

Source: NOAA NCEI Storm Events Database (forecast-zone records count on every county the zone covers).

When do volcanic ash records happen?

44% of its volcanic ash records since 1997 fell in June and July. The busiest month is July.

The values, month by month

Jan 0 · Feb 3 · Mar 11 · Apr 5 · May 6 · Jun 1 · Jul 30 · Aug 1 · Sep 12 · Oct 1 · Nov 0 · Dec 0 (records).

Source: NOAA NCEI Storm Events Database, records by the month they began.

The most recent volcanic ash records

To June 30, 2026
DateRecordCharacterKilledInjuredDamage
2001-07-29 Volcanic AshBayamón Municipio and 6 more, PR · forecast zone San Juan And Vicinity 0 0 $500K

Source: NOAA NCEI Storm Events Database.

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