Two cold fronts moved across Southwest California during this period. On 4/7/01, the first front brought between one and two and a half inches of rain.
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.
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 episode as NWS SGX wrote it up.
Two cold fronts moved across Southwest California during this period. On 4/7/01, the first front brought between one and two and a half inches of rain. Record cold temperatures followed that night and into 4/09/01. On the afternoon of 4/09/01, the second cold front arrived bringing thunderstorms with snow and hail. During that night and the morning of 04/10/01, two to six inches of snow fell between 3000 and 6000 feet with light to moderate snow at the 2250 feet level. In the Laguna Mountains, four separate groups of people, consisting of 52 men and 13 women, were rescued by the U. S. Border Patrol. They had been walking north from the United States/Mexico border and were found to be suffering the first stages of hypothermia. Spring Break campers and bikers in the Palomar Mountains had to abandon these outdoor activities. One man was injured when he drove off the road due to dense fog and snow. In the Tenaja Falls area of the Santa Ana Mountains a group of nine lightly-clad hikers became lost on the afternoon of 04/08, but were able to ward off the freezing overnight temperatures by huddling together. They were rescued the morning of 04/09.
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 7, 1:20 AM PST, 4 hours 40 minutes earlier.
EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
220 AM PDT SAT APR 7 2001
...SYNOPSIS...
A PACIFIC STORM SYSTEM WILL MOVE THROUGH TODAY AND BRING RAIN AND
SNOW TO MOST AREAS. RAINFALL AMOUNTS WILL GENERALLY BE NEAR OR
SLIGHTLY UNDER 1/2 INCH EXCEPT FOR HIGHER AMOUNTS ON SOUTH AND WEST
SLOPES OF ORANGE AND SAN BERNARDINO COUNTIES...AND LESS IN THE
DESERTS. IT WILL BE WINDY OVER THE MOUNTAINS AND DESERTS. SOME
CLEARING AND WARMING SHOULD OCCUR SUNDAY BEFORE ANOTHER SYSTEM
BRINGS A CHANCE OF PRECIPITATION MONDAY AND TUESDAY. A GRADUAL
WARMING TREND SHOULD OCCUR LATER NEXT WEEK.
...DISCUSSION...
RAIN IS STARTING TO SPREAD INTO ORANGE COUNTY. EXPECT MOST AREAS TO
RECEIVE AT LEAST SOME RAIN TODAY...ESPECIALLY NORTH. 06Z MSO IS
DEFINITELY THE PREFERRED MODEL AS IT SEEMS TO BE TRACKING THE VORT
MAX NW OF SFO WELL...AND THE 00Z MSO WAS GOOD TOO...UNLIKE THE 00Z
NOGAPS WHICH SEEMS TO BE OVERDOING THE SYSTEM WITH THE VORT MAX
BEING TRACKED TOO FAR SOUTH. MOST LIKELY...THE VORT MAX WILL STAY
JUST NORTH OF THE NORTHERN END OF OUR FORECAST AREA. SATELLITE
INDICATES PRETTY GOOD MOISTURE EXTENDING AT LEAST 200 MI SW OF PT
CONCEPTION...SO THIS WILL CERTAINLY CONTRIBUTE POSITIVELY TO THE
RAIN TOTALS.
IT IS ALREADY QUITE COLD IN THE MOUNTAINS...SO THE SNOW LEVELS
SHOULD START AT AROUND 4000 FEET AND REMAIN THERE THROUGH THE DAY.
GENERALLY...AMOUNTS SHOULD BE 3-8 INCHES...DEPENDING ON
LOCATION/ELEVATION. WINDS ALOFT...LIKE AT 700 MB ARE QUITE STRONG
AND SHOULD PEAK AROUND 18Z. THE MOUNTAIN WAVE ACTION CAN BE SEEN ON
THE MSO...WHICH HAS GOOD DVV AT 700 MB OVER THE DESERTS. THE DVV
PEAKS THIS MORNING...BUT THE NORMAL DIURNAL PATTERN HAS MOST
FAVORABLE WINDS IN THE AFTERNOON...SO OVERALL IT SHOULD BE WINDY ALL
DAY. THUS...A WIND ADVISORY HAS BEEN ISSUED FOR THE DESERTS UNTIL 6
PM.
THE NEXT SYSTEM COULD BRING SHOWERS MONDAY AND/OR TUESDAY. THE VORT
MAX SO FAR IS TRACKED FURTHER SOUTH...AND THERE COULD BE MORE
INSTABILITY. AFTER THAT...WE REMAIN IN SOME CYCLONIC FLOW AS A
WEAKER CLOSED LOW GOES BY TO THE SW...IF THE NEW AVN VERIFIES. DUE
TO THE CYCLONIC FLOW AND TOO SLOW OF TRANSITION TOWARDS EVENTUAL
HIGH PRESSURE ALOFT...I HAVE CUT BACK ON SOME TEMPS AND ADDED SOME
CLOUDS TO THE WED-FRI PERIOD.
SAN 74-
.SAN...WINTER WEATHER ADVISORY 55/56/58.
WIND ADVISORY 60/61/62.
MAXWELLThe national radar mosaic for the moment the first event began.
2 winter weather. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2001Every state in 2001This day in weather historyWarnings in California, April 2001
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 2026-10-01. Each event’s entry at NCEI: 5237551, 5237552.