Flash Flood and Flood in California, July 18, 2002

Name: Flash Flood and Flood in California, July 18, 2002
Start: 2002-07-18T11:45
End: 2002-07-18T15:00
Location: California

July 18, 2002 · NWS REV · 3 events in 1 county or zone

, CA cause flash flooding with 3 to 4 inches of water running down the roads in Hirschdale, CA. and flooding along Trout Creek.

Where it happened

Every event with a place to put it; 2 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: None recorded
Crop damage: None recorded
Events: 3

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.

What happened

The episode as NWS REV wrote it up.

Severe thunderstorms moving through Nevada Co., CA cause flash flooding with 3 to 4 inches of water running down the roads in Hirschdale, CA. and flooding along Trout Creek. Spotter reports of 1 inch hail also accompanied these storms.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Reno, NV wrote its last area forecast discussion before the first event at Jul 18, 8:45 AM PST, 3 hours earlier.

Area forecast discussion, Jul 18, 8:45 AM PST, 3 hours before

WESTERN NEVADA AND EASTERN CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
945 AM PDT THU JUL 18 2002

AIRMASS OVER WRN NV AND SIERRA REMAIN MOIST AND UNSTABLE WITH
VORT MAX NEAR SAC THIS MORNING. FORECAST LI OF -4 AND CAPE AROUND
1100 J/KG BY AFTN. K INDEX FAIRLY LOW AT 20 MAINLY DUE TO DRY AIR
AT 700 MB. SFC DEWPOINTS IN MID 40S TO LOWER 50S AND CONVECTIVE
TEMP OF 78 TRIGGERING AT 18Z. STEERING WINDS FAIRLY LIGHT BETWEEN
700 AND 500 MB LESS THAN 15 KTS. WILL ISSUE FF WATCH FOR SRN CWA
UNTIL 6 PM DUE TO SLOW MOVEMENT OF STRONG TSTMS. VORT MAX MOVES E
OF AREA FRIDAY BUT WITH RESIDUAL MOISTURE AND INSTABILITY WILL KEEP
SLGT CHC TSTMS MOST AREAS. ANOTHER VORT MAX MOVES TO CENTRAL CA CST
ON SAT FOR MORE TSTMS THIS WEEKEND. CYLKE

.REV...FLASH FLOOD WATCH NVZ01..02..03..04...CAZ073 UNTIL 6 PM.

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 flash flood, 1 flood, 1 hail. Local standard time, as filed.

Flash Flood, Nevada

When: July 18, 11:45 AM PST to 12:45 PM PST
Where: Nevada County, 5 mi NE of Truckee/Tahoe Arpt
Reported by: TRAINED SPOTTER
Coordinates: 39.301, -120.769 (the zone’s center; the record gives no point)

Flood, Nevada

When: July 18, 12:00 PM PST to 3:00 PM PST
Where: Nevada County, 5 mi W of Truckee
Reported by: TRAINED SPOTTER
Coordinates: 39.301, -120.769 (the zone’s center; the record gives no point)

Hail, Nevada

When: July 18, 12:15 PM PST to 12:30 PM PST
Where: Nevada County, 6 mi W of Truckee
Measured: 1 in hail
Reported by: TRAINED SPOTTER
Coordinates: 39.333, -120.300

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.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.
Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.

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

The same day elsewhere

Every storm in California in 2002 Every state in 2002 This day in weather history Warnings in California, July 2002

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: 5314706, 5314708, 5314707.