Sonoma County

Every recorded tornado

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

Tsunamis

1. Places where NOAA's Global Historical Tsunami Database records a tsunami's water arriving, with the greatest height it reached above sea level at the time. Only tsunamis NOAA rates probable or definite are counted. Heights from eyewitness accounts and tide gauges are mixed, and older events are less completely recorded.

NOAA NCEI/WDS Global Historical Tsunami Database, 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 CA GS (11,695), NASA (24), USGS Conterminous (6), USGS CA SF Bay Dec 2022 - Jan 2023 (3).

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. Jan 1, 2006Flood$104 million
   National Weather Service narrative

   The major flooding that began late in December continued into early January. Widespread low-land flooding across the county persisted with the hardest hit areas around the Russian River in Healdsburg and Guerneville. The Petaluma River also over-flowed its banks as did the Sonoma Creek. Total number of structures tagged by county officials with damage was 66 with property damage over $100 million.

2. Dec 31, 2005Flood$104 million
   National Weather Service narrative

   Widespread low-land flooding occurred across Sonoma County with mainstem river gages along the Russian River remaining above flood stage for several days. Devastating flooding occurred near the Russian River in Healdsburg as well as Guerneville. The Petaluma River overflowed its banks as well, as did the Sonoma Creek. Approximately 66 structures were tagged by county officials as significantly damaged in the wake of the flooding. An average of 4 to 6 inches of rain fell over a 24 hour period, 2 days after 1 to 3 inches drenched the same area. The flood continued to affect the area into early January.

3. Apr 1, 2006Debris Flow, North Bay Interior Valleys$14.4 million
   National Weather Service narrative

   Persistent heavy rainfall caused a massive number of landslides across the Sonoma and Marin County valleys area during the first half of April. About $20 million of damage was done to agriculture, with over $9 million spent in road repair damage in Sonoma County alone. Over $5 million worth of damage was done to single family dwellings in Sonoma - with lesser (but still substantial) amounts of damage experienced to businesses and public buildings. In Marin county the hardest hit areas were Mill Valley, Fairfax and San Rafael. In Mill Valley a man was killed after he was buried in a mudslide in his back yeard.

4. Feb 3, 1998Flash Flood$5.0 million
5. Feb 2, 1998Flash Flood$2.0 million
   National Weather Service narrative

   Flash Flood on Willow Brook at Stoney Point Road near Petaluma. 25 homes near the river were evacuated as well as 40 to 50 residents of a Mobile home park.

6. Jan 25, 2001Lightning$1.0 million
7. Dec 5, 1998Tornado$1.0 million
8. Mar 25, 2011Debris Flow, North Bay Interior Valleys$855,000
   National Weather Service narrative

   In San Anselmo heavy rain and strong wind caused mudslides, trees to blow down and power poles to topple. The following are other damage reports from around the city. On Florence Road trees fell into the public right of way blocking the roadway and crushing a car. It also took down several PGE, cable and telephone poles. On Woodruff Ave, a mudslide traveled 1/4 mile down the road carrying structure debris and blocking a main intersection that accesses 12 homes. On Scenic Ave, a mudslide entered a roadway and wind blew down a few power poles. At 29 Summit Ave, a mudslide closed roads; caused water, gas and sewer lines to break and took out numerous trees. On Redwood Rd, the road…

9. Jan 25, 2008Flash Flood$800,000
   National Weather Service narrative

   Very heavy rain caused flash flooding around Petaluma late Friday night, January 26th. The Petaluma River near Corona Road went over its flood stage of 25.5 feet reaching nearly 30 feet. At least a dozen homes were flooded as were several businesses.

10. Dec 27, 2006Strong Wind, Coastal North Bay Including Point Reyes National Seashore$500,000
    National Weather Service narrative

    Strong winds - sustained at least up to 30 mph hit the Marin County Coast - causing a tree to fall on a restaurant.

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

115°FSep 6, 2022

All-time low

14°F2 times, most recently Dec 23, 1990

Warmest night

71°FSep 3, 1961

Coldest day

34°FDec 15, 1972

Wettest day

6.95 inFeb 4, 1937

Snowiest day

1.0 inJan 29, 1937

Hottest year

2014mean 60.0°F

Coldest year

1948mean 54.3°F

Wettest year

198384.65 in

Driest year

201312.63 in

Station Graton (USC00043578), 200 ft elevation, 7.9 miles from the population centre. Daily records from 1926 to October 6, 2026; 98.1% 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 USC00043578.
• 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.
• Tsunamis NOAA NCEI/WDS Global Historical Tsunami Database.
• 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.