Thunderstorm Wind, San Diego
- When
- April 9, 5:10 PM PST to 5:25 PM PST
- Where
- San Diego County, Alpine
- Reported by
- NEWSPAPER
- Coordinates
- 33.028, -116.770 (the zone’s center; the record gives no point)
Damaging Wind in California, April 9, 2001
A thunderstorm dropped small hail and heavy snow during the evening commute along Interstate 8. In a ten to fifteen minute period hail accumulated to a depth of one inch at the 1800 foot level while two inches of snow accumulated on the ground at 4000 feet.
Where it happened
Every event with a place to put it; 1 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
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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 SGX wrote it up.
A thunderstorm dropped small hail and heavy snow during the evening commute along Interstate 8. In a ten to fifteen minute period hail accumulated to a depth of one inch at the 1800 foot level while two inches of snow accumulated on the ground at 4000 feet. Twenty eight cars, two semi-tractor trailer rigs, and one tour bus slid off the road or rolled over in a seven mile stretch along the freeway due to the icy road surface and poor visibility. In all 38 people were hospitalized, mostly coming from injured passengers on the tour bus.
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 San Diego, CA wrote its last area forecast discussion before the first event at Apr 9, 1:30 PM PST, 3 hours 40 minutes earlier.
Area forecast discussion, Apr 9, 1:30 PM PST, 3 hours 40 minutes before
EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
230 PM PDT MON APR 9 2001
...SYNOPSIS...
A COLD WEATHER SYSTEM WILL MOVE THROUGH SOUTHWEST CALIFORNIA TONIGHT
BRINGING SHOWERS AND A CHANCE OF THUNDERSTORMS...AND SNOW SHOWERS
ABOVE 3000 FEET. THE SHOWERS WILL DECREASE OVERNIGHT. HIGH PRESSURE
TUESDAY AND WEDNESDAY WILL BRING DRY AND WARMER WEATHER. ANOTHER
SYSTEM THURSDAY WILL BRING WIND TO THE MOUNTAINS AND DESERTS. WEAK
HIGH PRESSURE WILL BRING DRY WEATHER AND MILD TEMPERATURES THROUGH
THE WEEKEND.
...DISCUSSION...
SHOWERS HAVE INCREASED THIS AFTERNOON AND A FEW TSTORMS SHOWING UP
ON RADAR AND SATPIX. SO FAR SITUATION UNDER CONTROL. SFC HEATING
LIKELY TO GENERATE TSTORMS WITH LOCALLY HEAVY RAIN INTO THIS EVE.
EXPECTED SNOW AMOUNTS NOT QUITE ENOUGH TO ISSUE ADV...BUT WILL KEEP
EYE ON IT. WILD WX POSSIBLE OVER CSTL WATERS...MARINE STATEMENT
SUFFICIENT FOR NOW.
MODELS PUT MOST COLD AIR RIGHT OVER AREA THIS EVE. SNOW LEVELS WILL
DROP TO AROUND 3K FT BUT SNOW AMOUNTS ONLY A FEW INCHES AT HIGHER
ELEVS. TSTORM ACTIVITY SHOULD END AFTER SUNSET WITH SFC HEATING...
AND TAPERING OFF POPS FROM N TO S OVERNIGHT. A FEW LINGERING SHOWERS
POSSIBLE IN SAN FOOTHILLS AND MTNS EARLY TUE AM. A DRY BREAK FOR
MOST OF TUE AND WED WITH TEMPS INCHING UPWARD BEFORE ANOTHER
SHORTWAVE SLIDES DOWN CST BY EARLY THU AM. IT COULD ARRIVE BY WED
EVE. MORE INLAND TRACK MEANS DRIER SYSTEM...BUT AVN DOES PUT A
COUPLE HUNDREDTHS OVER AREA W OF MTNS. ITS A SLIGHT CHANCE SITUATION
THU...SO IN EXTENDED PUT CHANCE POPS IN FOR MTNS BUT NOWHERE ELSE.
WIND FOR SURE ESPECIALLY MTNS/DESERTS...MAYBE ADV LEVELS. HIGH
AMPLITUDE PATTERN FLATTENS OUT FRI AND SAT TO A FLOW ABOUT AS ZONAL
AS YOU CAN GET. SOME HIGH CLOUDS AND SOME COASTAL LOW CLOUDS THROUGH
WEEKEND WITH NEAR OR SLIGHTLY BELOW NORMAL TEMPS.
SAN 720
.SAN...MARINE WEATHER STATEMENT...SEE LAXMWSSAN.
MMThe radar
The San Diego radar (KNKX), 28 km away, was scanning. The volume nearest the first event began at 01:12 UTC.
Event by event
1 thunderstorm wind. Local standard time, as filed.
What these are
- Thunderstorm Wind
- Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Hail and Damaging Winds in Ohio, April 9, 2001
- Tornado and Hail in Ohio, April 9, 2001
- Tornadoes and Flash Flooding in Missouri, April 9 to 10, 2001
- Damaging Wind in California, April 9, 2001
- Hail and Damaging Winds in Indiana, April 9 to 10, 2001
- Heavy Snow in Montana, April 9, 2001
- Flash Flood and Flood in Pennsylvania, April 9, 2001
- Hail in Michigan, April 9, 2001
- Tornado and Hail in Illinois, April 9 to 10, 2001
- Damaging Wind in Pennsylvania, April 9, 2001
- Tornadoes and Hail in Pennsylvania, April 9, 2001
- Heavy Rain in New York, April 9 to 10, 2001
More
Every storm in California in 2001Every state in 2001This day in weather historyWarnings in California, April 2001
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: 5237422.