Photo: The Sands of Time 0 · CC BY-SA 4.0More hazard damage per building is expected in Sunnyvale than in 92% of U.S. towns, mostly from earthquakes
On FEMA’s National Risk Index, Sunnyvale gets a D for hazard risk: higher expected damage per building than 92% of U.S. towns, #423 of 847 in California. Most of that expected damage is earthquakes (62%), then river and rain flooding (38%). Flood insurance has paid 5 claims here since 1983.
Graded on FEMA’s expected yearly building damage per dollar of building value (NRI v1.20, December 2025), weighted by where residents live; flood claims are shown, not graded. How hazard risk is graded
What Sunnyvale faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
Earthquakes
River and rain flooding
Shares are of FEMA’s expected building damage, the measure the grade uses; ranks compare each hazard’s building-damage rate with all 85,154 U.S. census tracts. In FEMA’s terms, river and rain flooding is FEMA’s “Inland Flooding” (rivers and streams overflowing their banks, or rain overwhelming drainage). FEMA defines coastal flooding as high or rising tides and storm surge, so surge damage is counted there. Drought isn’t listed: FEMA counts its losses in crops only.
What’s behind Sunnyvale’s grade
Earthquakes are 62% of the building damage FEMA expects in Sunnyvale, and Sunnyvale’s rate of earthquakes damage is in the top 4% of U.S. census tracts. Next is river and rain flooding at 38% (higher than 77% of U.S. census tracts).
D #423 of 847 in California; higher expected damage per building than 92% of U.S. towns (21,298).
Sunnyvale’s residents live in 39 census tracts; FEMA’s figures are combined by where they live.
The typical California town has higher expected damage than 92% of U.S. towns; within the state, Sunnyvale has less expected damage per building than 50% of California towns.
Among the 400 U.S. cities of 100,000 or more, Sunnyvale has higher expected damage per building than 87% (#349 of 400). Because it is so big, its total expected yearly loss, $114M, is the 95th largest of those 400.
Does Sunnyvale flood? Rarely: 5 flood claims since 1983
Every paid claim on a federal flood insurance policy in Sunnyvale, from FEMA’s records: 0.1 per 1,000 homes, fewer than 99% of the 13,809 U.S. towns with a flood insurance record.
- The Pineapple Express - Southern1 claim · $6K
Sunnyvale is in FEMA’s Community Rating System (class 7) for its flood-proofing work.
Insurance rates: Santa Clara County.4 federal disasters brought FEMA money to Sunnyvale
Disasters that paid out in Sunnyvale itself (aid to households or repair grants to the City of Sunnyvale), newest first, with that year’s flood claims.
- 2023Severe Winter Storms, Straight-line Winds, Flooding, Landslides, and Mudslides$333K to the City of Sunnyvale for repairs
- 2022Severe Winter Storms, Flooding, Landslides, and Mudslides11 households applied for aid$600 aid approved
- 2020Wildfires59 households applied for aid$6K aid approved
- 2017Severe Winter Storms, Flooding, and Mudslides$13K to the City of Sunnyvale for repairs
Santa Clara County has had 19 natural disasters declared by the President since 1953, most often severe storms, then floods. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Also 3 FEMA wildfire suppression grants (Fire Management Assistance, not a disaster declaration) for fires in Santa Clara County, 2002–2020.
Old photos of Sunnyvale after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Sunnyvale archive →Sunnyvale and its neighbors
Sunnyvale is 2nd of the 7 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Mountain View | Dmore damage than 92% | earthquakes | 5 |
| Sunnyvale | Dmore damage than 92% | earthquakes | 5 |
| Cupertino | Dmore damage than 94% | earthquakes | 10 |
| Los Altos | Dmore damage than 95% | river and rain flooding | 4 |
| Fremont | D−more damage than 95% | earthquakes | 9 |
| San Jose | D−more damage than 97% | earthquakes | 389 |
| Santa Clara | D−more damage than 98% | river and rain flooding | 16 |
Hazard risk = FEMA’s expected yearly building damage per dollar of building value, vs. the 21,298 U.S. towns we grade; the map is shaded by fifths of the same scale. Flood claims = paid federal flood insurance claims on record.
Get ready for what Sunnyvale faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- Turn around at flooded roads: a foot of moving water can carry off a car.
- Flood insurance usually takes 30 days to start, so buy it before the forecast.
- Keep papers and medicines up high, in a grab-and-go bag.
- Look up the address on FEMA’s flood map.
- Ask the seller or landlord whether it has ever flooded, and what flood insurance costs there.
- Get a flood insurance quote early: policies usually start 30 days after you buy.
- Sunnyvale residents get 15% off flood insurance.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in Sunnyvale
Is Sunnyvale at risk for natural disasters?
On FEMA’s National Risk Index, Sunnyvale has higher expected damage per building than 92% of U.S. towns: D for hazard risk, #423 of 847 in California. Most of the expected damage is earthquakes (62%) and river and rain flooding (38%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Sunnyvale flood?
Flood insurance has paid 5 claims in Sunnyvale since 1983, $69K in all, or 0.1 per 1,000 homes, fewer than 99% of U.S. towns with a flood insurance record. The most claims came from Pineapple Express - Southern (1).
Is Sunnyvale in a flood zone?
Flood zones are drawn street by street, so the answer depends on the address: look it up on FEMA’s flood map. In Santa Clara County, 22% of homes in mapped flood zones carry federal flood insurance, and 1.7% of all homes do.
How much is flood insurance in Sunnyvale?
Sunnyvale is in FEMA’s Community Rating System (class 7), which takes 15% off federal flood insurance policies for its flood-proofing work. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in Sunnyvale?
By FEMA money that reached Sunnyvale, Severe Winter Storms, Straight-line Winds, Flooding, Landslides, and Mudslides (2023): $333K to the City of Sunnyvale for repairs. By flood claims, Pineapple Express - Southern: 1 paid, $6K.
Is Sunnyvale at risk from earthquakes?
It is the largest share of the building damage FEMA expects here (62%), and Sunnyvale’s rate for it is in the top 4% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Sunnyvale.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Sunnyvale’s residents lived in the 2020 census; OpenFEMA: NFIP redacted claims, multiple-loss properties, community status book and residential penetration rates, housing assistance (owners and renters), public assistance funded projects, hazard mitigation properties and disaster declarations. Homes: Census ACS 2020–24. Preparedness tips: Ready.gov. FEMA’s model is an average of expected damage, not a forecast. How hazard risk is graded.