Calaveras County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Calaveras 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.

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 NASA (8).

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. Feb 9, 2017Flood$7.0 million
   National Weather Service narrative

   East and west bound SR-26 were closed from Iris Way to the North Fork Mokelumne River Bridge due to flooding and a slope failure.

2. Feb 14, 2019Flood$500,000
   National Weather Service narrative

   Local media reporting flood waters running over Pool Station Road caused road on bridge to crack.

3. Sep 9, 1999Wildfire$290,000
   National Weather Service narrative

   The Winton Incident was responsible for burning 120 acres. Fire suppression costs totaled $450,000. Moderate winds as well as steep terrain hampered the control process. Two homes and two out buildings, one car and one recreational vehicle were destroyed.

4. Dec 31, 2022Flood$100,000
   National Weather Service narrative

   Fifteen people had to be rescued from the Castle Oaks mobile home park. Multiple homes and townhouses flooded in La Contenta.

5. Feb 9, 1999Flash Flood$20,000
   National Weather Service narrative

   Cosgrove Creek left its banks, surrounded four homes, poured into a low-lying golf course, threatened sewage treatment ponds, and temporarily closed Highway 26.

6. Mar 11, 2023Flash Flood$20,000
   National Weather Service narrative

   Calaveras County Sheriff Dispatch reported significant roadway flooding with two houses flooded in Copperopolis.

7. Jan 10, 2023Thunderstorm Wind$11,000
   National Weather Service narrative

   Tree and powerlines across the entire roadway of SR26. There was a gust of 40 mph measured at Barton PGE.

8. Dec 22, 2015Debris Flow$10,000
   National Weather Service narrative

   There were three incidents reported in the Butte Fire area. Mud and debris covered Hawver Rd. at Jesus Maria Road in Mokelumne Hill along Calaveras River. Road was closed until the debris was cleared. That intersection has a small makeshift bridge over the creek that is made of concrete over about 8 six inch pipes that lie in the river bed. The pipes clogged and the creek overflowed the small bridge. There were also a few small rock slides and mud slides along some of the highways. Highway 26 and Woodhouse Mine Road in West Point had a mud slide, but this did not close the road. The road is open however. There was also a small rock slide on Mountain Ranch Road at Rocky Road.

9. Mar 5, 2016Debris Flow$5,000
   National Weather Service narrative

   Caltrans reported flooding and debris on Highway 26 between Mokelumne Hill and Glencoe, within the Butte Fire burn area.

10. Jan 10, 2023Thunderstorm Wind$1,000
    National Weather Service narrative

    There was a large tree reported down across SR12. There was a gust to 38 mph measured at Mills Ave in eastern San Andreas.

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

113°F2 times, most recently Jul 15, 1972

All-time low

8°F2 times, most recently Dec 10, 1972

Warmest night

79°FAug 8, 1921

Coldest day

33°F2 times, most recently Dec 9, 1972

Wettest day

5.42 inDec 11, 1906

Snowiest day

11.0 inJan 1, 1910

Hottest year

1934mean 62.5°F

Coldest year

1964mean 55.1°F

Wettest year

194046.67 in

Driest year

20139.53 in

Snowiest season

44.0 in1932-33

Station Sonora (USC00048353), 1,675 ft elevation, 19.2 miles from the population centre. Daily records from 1906 to October 27, 2026; 88.4% 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 USC00048353.
• 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.