Boulder County, Colorado

What hazards hit Boulder County most?

The most frequent records are winter storm records: 800 since 1996. The rank column places the county among Colorado's counties by days with a record per 1,000 square miles of land over each hazard's complete period.

Source: NOAA NCEI Storm Events Database (county and forecast-zone records attributed to the county; a zone record shows its own totals on each county it covers). Days: dates with at least one record of the hazard in the county. Ranks: days with a record per 1,000 square miles of land (Census Bureau 2024 Gazetteer), since 1950 for tornadoes, 1955 for hail and thunderstorm wind, 1996 for the rest.

How many tornadoes has Boulder County had?

NOAA records 11 tornadoes in Boulder County from 1953 to 2015, the strongest rated EF3, with 0 deaths and 0 injuries recorded in the county. That is 25th of 63 Colorado counties by days with tornadoes per 1,000 square miles since 1950. A tornado that crossed a county line is counted in each county it touched, with the length of its path inside the county.

Counted as whole tornadoes rather than county records, the Storm Prediction Center's database holds 11 tornadoes whose track touched Boulder County since 1950 (NOAA's county records number 11, the same count); along their whole tracks they killed 0 people.

Map of the strongest tornado tracks in Colorado.

Source: NOAA NCEI Storm Events Database, tornado records by county (path length in the county, maximum width); ratings as published: F scale before February 1, 2007, EF scale after. Whole-track figures: NOAA Storm Prediction Center tornado database (1950-2025). SPC severe weather database.

When was the last damaging storm in Boulder County?

The most recent record with damage, injuries or deaths is the December 17, 2025 high wind ($300,000 in damage in 2025 dollars).

A 91 mph wind gust occurred in the middle of Boulder and a 87 mph wind gust was measured at the Boulder Airport. Multiple trees were blown down on the University of Colorado campus. Powerline poles were blown over north of Golden along highway 93 and near the intersection with 64th Parkway. Boulder Valley School District estimated $250,000 in damage from the wind storm to its schools/buildings. The following highways were closed due to the high winds...Highway 128 from Superior to Highway 93, Highway 93 between Boulder and Arvada, and Highway 36 between Boulder and Lyons. Several reports of car and structure windows broken by flying debris and flying rocks.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 1300897)

Source: NOAA NCEI Storm Events Database; every record of 2025-2026 is listed, earlier ones when they caused deaths, injuries or $250,000 of damage (2025 dollars), and every tornado.

The deadliest and costliest records

Source: NOAA NCEI Storm Events Database: deaths and injuries direct and indirect; damage is property plus crops as estimated by the National Weather Service, converted to 2025 dollars.

Is it getting more frequent?

Records per decade for Boulder County's most frequent hazards. Counts rose everywhere after 1996, when NOAA began recording every event type, so compare decades within a hazard's complete period only (the shaded cells come before it).

Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).

What time of year?

Records by month in Boulder County. The two busiest months are in violet.

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

Federal disaster declarations for Boulder County

FEMA's register lists 19 declarations that include Boulder County: 7 major disasters, 5 emergencies and 7 fire management assistance declarations. Most were for fire (9) and flood (5).

Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), declarations through October 2, 2026; one declaration is counted once however many areas it names. OpenFEMA dataset page.

How many floods has Boulder County had?

NOAA's Storm Events Database holds 37 flood or flash flood records for Boulder County from 1997 to 2021, on 21 days, with 4 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Boulder County ranks 204th of 2,942 U.S. counties.

The National Flood Insurance Program has paid $50.1 million on 1,784 claims filed in Boulder County; the most in one year was 1,520 in 2013. Claims count insured losses only: uninsured flood damage is not in this file.

Source: FEMA OpenFEMA NFIP Redacted Claims, as of September 8, 2026; claims by year of loss, payments in the dollars of the year paid. OpenFEMA dataset page.

FEMA's modeled risk for Boulder County

FEMA's National Risk Index rates Boulder County Relatively Moderate overall, with an expected annual loss of $125 million. These are FEMA's model estimates of future loss from 18 hazards, not a count of what happened; they can differ from the record above.

Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.

Counties that share a border with Boulder County

1. Weld County 2,459
2. Larimer County 1,978
3. Boulder County 1,789
4. Jefferson County 1,455
5. Grand County 1,114
6. Broomfield County 119
7. Gilpin County 108

Source: U.S. Census Bureau county adjacency file; NOAA NCEI Storm Events Database, records since 1950. The Census Bureau's adjacency file.

Next

• Tornadoes in ColoradoEvery Colorado tornado since 1950 and the counties with the most per square mile
• Winter storms in ColoradoThe state's winter storm records, by county, year and month
• The Colorado recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in Boulder CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Boulder County's FEMA declarations (CSV)19 rows: every declaration that named the county, for your own analysis