Jefferson County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Jefferson County: 0.
2. Weak tornadoes were under-recorded before Doppler radar coverage became national in the early 1990s, so earlier decades read low. Ratings use the Fujita scale before February 2007 and the Enhanced Fujita scale after.

Storm Prediction Center severe weather database, 1950 to 2025.

Every large fire

1. Large fires mapped by the Monitoring Trends in Burn Severity program since 1984: 1,000 acres or more in the West, 500 or more in the East. Prescribed burns are excluded. Acres here are the part of each perimeter inside this place.

Monitoring Trends in Burn Severity (USGS and U.S. Forest Service), 1984 to 2026.

Smoke overhead

1. A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.

NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.

Claims by ZIP code

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.

River crests

River gauges

1. Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.

NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.

1. The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.

NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.

Every earthquake of magnitude 4 or more within 50 miles

1. Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the county boundary (or inside the county).
2. Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).

USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.

Volcanoes within 100 miles

1. U.S. volcanoes within 100 miles, from the USGS Volcano Hazards Program. The threat category is the USGS 2018 National Volcanic Threat Assessment, which ranks volcanoes by how hazardous their past eruptions were and how many people and how much infrastructure lie near them. It is not a forecast of eruption.

USGS Volcano Hazards Program, retrieved October 30, 2026.

Mapped landslides

Mapped by USGS CO Front Range Sept 2013 (328), CO GS (124), NASA (6).

1. Landslides mapped in the USGS compilation of landslide inventories across the United States (version 3.0, 2025), rated probable or better. The compilation joins inventories made by federal and state agencies for different purposes and areas, so the number mapped in a county reflects how closely it has been surveyed as much as how often its slopes fail. An area with few records may simply not have been mapped. Deaths are as recorded in the inventories; a slide listed in two inventories is counted once.

USGS Landslide Inventories across the United States, version 3.0, retrieved October 27, 2026.

More event types since 1996

Costliest events since 1996

1. May 8, 2017Hail$2.3 billion
   National Weather Service narrative

   The estimated damage is for the entire episode.

2. Jul 20, 2009Hail$350 million
   National Weather Service narrative

   A severe thunderstorm produced damaging winds, large hail and very heavy rain across the western and southern suburbs of Denver. Widespread damage was observed in the cities of Arvada, Wheat Ridge and Lakewood. The intense straightline winds were the result of a wet microburst which downed hundreds of trees and snapped power poles. Winds gusts to 80 mph were reported along with nickel to golfball size hail. The combination of wind and hail produced widepread damage to homes and vehicles. The damage claim estimates totaled $350 million; about 32,900 claims were filed for homes, while another 19,500 claims were for vehicles. As many as 90,000 homes and businesses were left without…

3. Aug 11, 1997Flash Flood$128 million
   National Weather Service narrative

   Large hail, strong winds and torrential rain hammered portions of Lakewood and South Denver. Nearly 1 inch of rain fell in the span of 10 minutes in South Denver with a storm total of 1.81 inches reported. Street flooding was extensive as gutters and other drainage systems in the area were clogged by hail, piled several inches deep, as well as other debris. In addition, extensive damage to cars, homes and businesses was reported as strong thunderstorm winds to 50 mph and large hail accompanied the heavy rain. Several trees were downed by the strong winds and trees stripped of their leaves by the hail. A water lily exhibition on display at the Denver Botanic Gardens was heavily…

4. Jun 12, 2000Wildfire$12.0 million
   National Weather Service narrative

   Two large wildfires developed in the Front Range Foothills of Colorado as careless campers and very dry conditions proved to be a dangerous combination. Strong winds gusting in excess of 60 mph on the 13th, fanned the flames, spreading both wildfires out of control. The Hi Meadows wildfire, about 35 miles southwest of Denver, consumed 10,800 acres and 80 structures, mostly high priced homes. The Bobcat wildfire, located about 12 miles southwest of Fort Collins, consumed 10,600 acres and 22 structures. Mother Nature, initially a nemesis to firefighters, also played the key role in dousing the flames. Late on the 16th, a strong cold front moved into northeastern Colorado. Upslope…

5. Sep 12, 2013Flood$6.0 million
   National Weather Service narrative

   Heavy rain, ranging from 6 to 16 inches through the storm event, caused widespread flooding and included the entire drainage systems of Bear, Coal, Clear, Leyden, Ralston and Van Bibber Creeks. In Arvada, Quaker St. near W. 82nd Ave. was closed due to flooding and infrastructure damage. Evacuations were ordered in the area of 68th Ave. and 82nd Ave., between McIntyre and Alkire Streets. Flooding washed out sections of W. 82nd Ave, east of CO93. Flooding was reported near the intersection of W. 92nd Ave. and Indiana St. A section of South Golden Road was washed out near Lena Gulch. Golden Gate Canyon was closed between CO93 and Robinson Hill. Many other roads in northern Jefferson…

6. May 20, 2002Wildfire$2.2 million
   National Weather Service narrative

   Lightning sparked a wildfire near Deckers. Extremely dry conditions and very strong winds the following day allowed the fire to consume 3,860 acres before it could be contained. Thirteen structures were destroyed, including 4 homes.

7. May 30, 2001Lightning$1.0 million
   National Weather Service narrative

   Lightning ignited a fire which destroyed a luxury home on Bear Mountain near Evergreen.

8. Jul 12, 1996Flash Flood$520,000
   National Weather Service narrative

   Very heavy rain from a fast moving thunderstorm dumped 2 to 3 inches of rain within an hour over southern Jefferson County. Two people were killed near the town of Buffalo Creek when a 20-ft wall of water blasted through the area. Utility poles and trees were uprooted, cars, propane tanks and bridges were destroyed in the flood's path. Entire buildings were moved off their foundations or heavily damaged in the floodwaters. The first fatality occurred along Highway 126, when the driver of a pickup was washed off the road by the deadly wall of water. The second death occurred further downstream when a man in a 5th wheel trailer was washed away. This was the second disaster to strike…

9. Jul 21, 2009Flash Flood$321,000
   National Weather Service narrative

   Heavy rain produced mudslides in the Hayman burn area. Trees, stumps, sticks, debris, and decomposed granite came down with the mudslides. Most of the damage occurred from Six Mile Creek to Forest Service Road 211 above the Wigwam Fishing Club. Road crews had to totally restore shoulders and slopes and cleaned out ditches downstream of draws and ravines. The mudslides washed out a 250-ft stretch of one shoulder of State Highway 126, near the turnoff to Cheesman Reservoir, and a large section of guard rail was washed out.

10. May 19, 2007Lightning$200,000
    National Weather Service narrative

    Lightning struck a 33-ft marble statue of Jesus at Mother Cabrini Shrine, in the foothills of Golden. The blast broke off one of the statue's arms and a hand, and also damaged a foot. The statue was sent from Italy in five stackable sections in 1954.

1. Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.

NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.

All-time high

104°F4 times, most recently Jun 29, 2018

All-time low

−25°F4 times, most recently Dec 22, 1990

Warmest night

72°FJul 25, 2003

Coldest day

−9°F2 times, most recently Feb 4, 1989

Wettest day

3.88 inSep 12, 2013

Snowiest day

23.6 inDec 24, 1982

Hottest year

1981mean 54.1°F

Coldest year

1951mean 48.4°F

Wettest year

201524.07 in

Driest year

19547.51 in

Snowiest season

99.3 in1958-59

Station Denver-stapleton (USW00023062), 5,286 ft elevation, 14.1 miles from the population centre. Daily records from 1948 to October 22, 2026; 98.7% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.

NOAA NCEI Global Historical Climatology Network Daily.

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.

Neighbouring counties

• Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
• Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
• Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
• Storm events NOAA NCEI Storm Events Database, through 2026.
• Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
• Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
• Weather records NOAA NCEI Global Historical Climatology Network Daily, station USW00023062.
• River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
• Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
• Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
• Volcanoes USGS Volcano Hazards Program, U.S. volcanoes and 2018 threat assessment.
• Landslides USGS Landslide Inventories across the United States, version 3.0 (2025).
• Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.

Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.