Debris Flow and Heavy Snow in California, March 1 to 2, 2015

Name: Debris Flow and Heavy Snow in California, March 1 to 2, 2015
Start: 2015-03-01T00:00
End: 2015-03-02T12:20
Location: California

March 1 to 2, 2015 · NWS SGX · 6 events in 5 counties and zones

An upper-level trough deepened along the West Coast before moving inland over Southern California and brought rain and snow showers, as well as a few thunderstorms with hail, through the morning of the March 3rd. Huntington Beach reported around one inch of hail accumulation during the morning of the 2nd.

Where it happened

Every event with a place to put it; 3 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: $1,000
Crop damage: None recorded
Events: 6

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.

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 Feb 28, 9:30 PM PST, 2 hours 30 minutes earlier.

Area forecast discussion, Feb 28, 9:30 PM PST, 2 hours 30 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 PM PST SAT FEB 28 2015

.SYNOPSIS...A DEEP SLOW-MOVING TROUGH OVER THE WEST COAST WILL BRING
SCATTERED SHOWERS...MOUNTAIN SNOW...AND COOL WEATHER THROUGH
TUESDAY. DRY AND WARMER FOR THE LATTER HALF OF THE WEEK WITH LOCALLY
GUSTY NORTHEAST WINDS AT TIMES.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

SCATTERED SHOWERS WERE FILLING THE RADAR BEAM THIS EVENING BUT
RAIN AMOUNTS HAVE BEEN MOSTLY LIGHT SO FAR. TOTALS RANGE FROM A
A LOW OF A FEW HUNDREDTHS OF AN INCH IN THE INLAND EMPIRE TO A
HIGH OF A HALF-INCH IN THE SAN DIEGO COUNTY MOUNTAINS. A PRECIP
SUMMARY IS HEADLINED ON OUR WEBPAGE.

SNOW WAS FALLING IN THE MOUNTAINS ABOVE 5500 FEET. 1-2" OF NEW
SNOW WAS REPORTED IN THE SAN BERNARDINO MOUNTAINS ABOVE 7000 FEET
THIS AFTERNOON.

SHOWERS EXTENDED WESTWARD OVER THE COASTAL WATERS ALL THE WAY
PAST PT CONCEPTION THIS EVENING. THESE SHOWERS WILL MOVE EASTWARD
ACROSS SO-CAL TONIGHT IN THE SOUTHWEST FLOW AHEAD OF A 500 MB CLOSED
LOW OVER SAN LUIS OBISPO COUNTY. THIS UPPER LOW WILL STALL OVER PT
CONCEPTION SUNDAY...SO SCATTERED SHOWERS IN THE MOIST SOUTHWEST
FLOW WILL CONTINUE OVER SOCAL. A SHORTWAVE WEST OF PT CONCEPTION
WILL ROUND THE BASE OF THE TROUGH SUNDAY AFTERNOON AND MAY ENHANCE
PRECIPIATION SUNDAY EVENING. THUNDERSTORMS ARE POSSIBLE MONDAY WHEN
THE TRAILING 500 MB COLD POOL AND STEEPER LAPSE RATES MOVES OVER THE
AREA.

A SECOND UPPER LEVEL DISTURBANCE WILL BRING ANOTHER CHANCE FOR MORE
SHOWERS MONDAY NIGHT INTO TUESDAY. HOWEVER...RECENT MODEL RUNS HAVE
TAKEN THIS SHORTWAVE AND ITS VORT MAX FARTHER WEST OVER THE OCEAN
MONDAY NIGHT...AND TAKE IT ACROSS NORTHERN BAJA TUESDAY. THIS
WESTERLY TRACK WOULD KEEP MOST OF THE PRECIP OVER-WATER AND
ONLY GRAZE SOUTHWEST CALIFORNIA WITH LIGHT PRECIP AS THE BULK OF
THE ENERGY PASSES BY TO THE SOUTHWEST.

WARMER WEDNESDAY THROUGH FRIDAY AS THE EASTERN PACIFIC RIDGE
OFFSHORE BUILDS BACK OVER CALIFORNIA AND INTO THE GREAT BASIN.
NORTHEAST WINDS BETWEEN THIS BUILDING RIDGE AND THE STALLED
CLOSED LOW OVER SONORA MEXICO WILL BRING A PERIOD OF MODERATE
OFFSHORE FLOW FOR THE LATTER HALF OF THE WEEK.

&&

.AVIATION...
010414Z...COASTS/VALLEYS/MOUNTAINS...MULTIPLE SCT-OVC
CLOUDS LAYERS BETWEEN 2000 AND 7000 FT MSL CONTINUING THROUGH SUNDAY
EVENING OVER AND  WEST OF THE MTNS. ISOLD LIGHT SHOWERS BECOMING
MORE WIDESPREAD AND HEAVIER LATE TONIGHT INTO SUNDAY MORNING. LOCAL
CIGS 1000-1500 FT MSL AND VIS 3SM OR LESS ARE POSSIBLE IN HEAVIER
SHOWERS...AND COASTAL SLOPES OF THE MTNS WILL REMAIN OBSCURED IN
CLOUDS AND PRECIP. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS SUN
AFTERNOON AND EVENING. THESE STORMS MAY PRODUCE SMALL HAIL...HEAVY
RAIN...AND BRIEF GUSTY WINDS.

DESERTS...GUSTY WEST WINDS WILL CONTINUE TO DIMINISH THIS EVENING.
ISOLD-SCT LIGHT SHOWERS WILL DEVELOP LATE SUN MORNING AND CONTINUE
THROUGH SUN EVENING WITH LOCAL VIS 3-5SM IN HEAVIER SHOWERS. THERE
IS A SMALL CHANCE OF THUNDERSTORMS DURING THIS TIME...MAINLY OVER
THE HIGH DESERT. OTHERWISE VARIABLE CLOUD LAYERS ABOVE 7000 FT MSL
AND UNRESTRICTED VIS THROUGH SUNDAY EVENING.

&&

.MARINE...
830 PM...PERIODS OF SHOWERS WILL OCCUR THROUGH MONDAY
NIGHT...WITH ISOLATED THUNDERSTORMS POSSIBLE LATE SUNDAY MORNING
THROUGH MONDAY NIGHT. THESE STORMS HAVE THE POTENTIAL TO PRODUCE
SMALL HAIL...BRIEF HEAVY RAIN...GUSTY WINDS...AND CLOUD-TO-WATER
LIGHTNING. THERE IS A CHANCE OF SHOWERS MONDAY NIGHT INTO TUESDAY.
NO HAZARDOUS MARINE WEATHER IS EXPECTED WED AND THU.

&&

&&

.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED...BUT REPORTS OF RAIN AND SNOW
TOTALS ARE APPRECIATED.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WINTER STORM WARNING UNTIL 4 PM PST MONDAY
     FOR RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY
     MOUNTAINS-SAN DIEGO COUNTY MOUNTAINS ABOVE 5000 FEET.

PZ...NONE.

&&

PUBLIC...MOEDE
AVIATION/MARINE...SS

The radar

The Edwards AFB radar (KEYX), 129 km away, was scanning. The volume nearest the first event began at 18:10 UTC.

Open the radar archive at this moment

Event by event

2 winter weather, 1 heavy snow, 1 hail, 1 funnel cloud, 1 debris flow. Local standard time, as filed.

Winter Weather, San Bernardino County Mountains

When: March 1, 12:00 AM PST to March 2, 7:00 AM PST
Where: San Bernardino County Mountains forecast zone
Reported by: Trained Spotter
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

A trace to 5 inches of snow was reported from 0000 PST on the 1st through 0700 PST on the 2nd across the area. The heaviest total of 5 inches was reported by a spotter 2 mi ESE of Big Bear City. Additional snowfall amounts of 4 inches in Forest Falls, 3 inches in Angelus Oaks, and 2 inches in Green Valley Lake were also reported. Multiple traffic collisions were reported in the mountain top district, especially along Highway 38 between Angelus Oaks and Hatchery Drive (Big Bear). The aforementioned section of Highway 38 was closed.

Heavy Snow, Riverside County Mountains

When: March 1, 3:00 AM PST to March 2, 8:00 AM PST
Where: Riverside County Mountains forecast zone
Reported by: Trained Spotter
Coordinates: 33.744, -115.994 (the zone’s center; the record gives no point)

Trained spotters in Idyllwild and Pine Cove both reported a 24 hour snowfall accumulation of 9.5 inches as of 0800 PST on the 2nd. A third spotter in Pine Cove reported 8 inches of snowfall in 12 hours, as of 2100 PST on the 1st.

Winter Weather, San Diego County Mountains

When: March 1, 5:00 AM PST to March 2, 8:00 AM PST
Where: San Diego County Mountains forecast zone
Reported by: Trained Spotter
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

At 2100PST on the 1st a trained spotter reported a 12 hour snowfall total of 7 inches at Palomar Mountain.

Hail, Orange

When: March 2, 10:10 AM PST to 10:40 AM PST
Where: Orange County, 1.07 mi S of Huntington Beach to 0.37 mi N of Boulevard Gardens
Measured: 0.5 in hail
Property damage: $100
Reported by: Law Enforcement
Coordinates: 33.655, -118.002

A series of thunderstorms dropped up to 1 inch depth accumulation of 0.5-in diameter hail on Huntington Beach. The hail covered the beach near Huntington Beach Pier and numerous roads within the city of Huntington Beach. The event received widespread attention from local and national media and extensive social media photos.

Funnel Cloud, Riverside

When: March 2, 10:50 AM PST to 11:05 AM PST
Where: Riverside County, 0.29 mi NE of Perris
Reported by: Social Media
Coordinates: 33.783, -117.227

The public reported a brief cold air funnel over Perris.

Debris Flow, Orange

When: March 2, 11:20 AM PST to 12:20 PM PST
Where: Orange County, 2.18 mi E of Silverado to 2.22 mi E of Silverado
Cause: Heavy Rain
Property damage: $1,000
Reported by: Emergency Manager
Coordinates: 33.747, -117.592

A band of rain and thunderstorms moved over the Silverado Burn scar between 1045 and 1200 PST on the 2nd, producing rain rates in excess of 0.5 inches per 30 minutes. As a result, a moderate mud flow occurred in the backyard of a local resident. Video was shared with NWS San Diego.

What these are

Winter Weather: Snow, sleet or freezing rain below warning levels that still caused disruption, damage or casualties.
Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.
Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Funnel Cloud: A rotating column of cloud extending from a thunderstorm that did not reach the ground.
Debris Flow: A fast-moving slurry of mud, rock and debris, usually on a slope soaked by heavy rain or stripped by a fire.

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

The same day elsewhere

Every storm in California in 2015 Every state in 2015 This day in weather history Warnings in California, March 2015

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: 567150, 567151, 567156, 567764, 567492, 567507.