California, 1998

Tornadoes and Flash Flooding in California, February 2 to 19, 1998

February 2 to 19, 1998 · NWS MTR · 13 events in 10 counties and zones

9 flash flood, 3 tornado, 1 high wind, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 10 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

Open the live radar over this ground

The toll

Deaths
0
Injuries
0
Property damage
$17 million
Crop damage
$500,000
Events
13

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

The radar

The San Francisco radar (KMUX), 84 km away, was scanning. The volume nearest the first event began at 00:01 UTC.

Open the radar archive at this moment

Event by event

9 flash flood, 3 tornado, 1 high wind. Local standard time, as filed.

Flash Flood, San Francisco

When
February 2, 4:00 PM PST
Where
San Francisco County, San Francisco
Coordinates
37.778, -122.442 (the zone’s center; the record gives no point)

Widespread road clousure, street flooding and a few mudslides.

Flash Flood, Sonoma

When
February 3, 4:00 AM PST
Where
Sonoma County, Rio Nido
Property damage
$5.0 million
Coordinates
38.525, -122.922 (the zone’s center; the record gives no point)

Flash Flood, Alameda

When
February 3, 11:00 AM PST
Where
Alameda County, East Portion
Coordinates
37.651, -121.918 (the zone’s center; the record gives no point)

breached levee along the Arroyo Mocho in Livermore. Water reached Pleasanton and sheared off a bike lane, guard rail and fence.

Flash Flood, Marin

When
February 5, 10:00 PM PST to February 6, 2:00 AM PST
Where
Marin County, Corte Madera
Coordinates
38.055, -122.749 (the zone’s center; the record gives no point)

Buildoings and streets in Corte Madera were flash flooded.

Flash Flood, Santa Cruz

When
February 6, 6:00 AM PST to 6:30 AM PST
Where
Santa Cruz County, Santa Cruz
Property damage
$250,000
Coordinates
37.022, -122.010 (the zone’s center; the record gives no point)

Flash Flood, Marin

When
February 6, 6:00 AM PST
Where
Marin County, South Portion
Property damage
$1.5 million
Crop damage
$500,000
Coordinates
38.055, -122.749 (the zone’s center; the record gives no point)

High Wind, San Francisco / San Mateo / Santa Cruz

When
February 6, 6:30 AM PST
Where
San Francisco / San Mateo / Santa Cruz forecast zone
Property damage
$50,000
Coordinates
37.778, -122.442 (the zone’s center; the record gives no point)

winds to 125 mph reported on Mt Diablo, widespread sustained winds of over 40 MPH.

Tornado, Santa Clara

When
February 6, 4:00 PM PST to 4:02 PM PST
Where
Santa Clara County, Sunnyvale
Rating
F0
Path length
0.1 mi
Path width
30 yd
Property damage
$100,000
Coordinates
37.370, -122.030

Very weak tornado touched down at Lockheed Martine plant in sunny vale with some minor damage.

Flash Flood, Monterey

When
February 6, 6:00 PM PST
Where
Monterey County, Pajaro
Property damage
$300,000
Coordinates
36.240, -121.309 (the zone’s center; the record gives no point)

Flash Flood, Monterey

When
February 6, 10:00 PM PST
Where
Monterey County, West Portion
Property damage
$10 million
Coordinates
36.240, -121.309 (the zone’s center; the record gives no point)

Highway One closed all along big Sur Coast due to Flash flooding and resulting mudslides , and portion of the road washing away. Road not opened until May 98.

Flash Flood, Contra Costa

When
February 7, 1:00 PM PST
Where
Contra Costa County, Walnut Creek
Coordinates
37.923, -121.951 (the zone’s center; the record gives no point)

Streets and businesses flash flood in Walnut Creek.

Tornado, San Mateo

When
February 7, 2:00 PM PST
Where
San Mateo County, Half Moon Bay
Rating
F0
Path length
0.2 mi
Path width
50 yd
Coordinates
37.470, -122.430

Weak tornado ripped up some trees. Appears it began as a waterspout and moved on shore.

Tornado, Contra Costa

When
February 19, 12:30 PM PST
Where
Contra Costa County, Brentwood
Rating
F0
Path length
0.2 mi
Path width
30 yd
Property damage
$50,000
Coordinates
37.930, -121.700

Weak tornado demolished a 120' by 40' shade structure at a nursery as well as a chicken coop nad a tool shed.

What these are

Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
High Wind
Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.
Tornado
A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in California in 1998Every state in 1998This day in weather historyThe tornado archive for California, 1998Warnings in California, February 1998

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5640251, 5640242, 5640243, 5640342, 5640238, 5640241, 5640239, 5640248, 5640240, 5640343, 5640344, 5640249, 5640250.