Heavy rain, falling across the Thomas Fire burn scar, resulted in significant mud and debris flows across sections of Ventura county. Highway 101, a main route from Ventura to Santa Barbara, was closed in several locations.
Every event with a place to put it. 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 LOX wrote it up.
Heavy rain, falling across the Thomas Fire burn scar, resulted in significant mud and debris flows across sections of Ventura county. Highway 101, a main route from Ventura to Santa Barbara, was closed in several locations.
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 Los Angeles, CA wrote its last area forecast discussion before the first event at Mar 22, 7:11 PM PST, 2 hours 46 minutes earlier.
Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
811 PM PDT Thu Mar 22 2018
updated marine discussion
.SYNOPSIS...22/640 PM.
The cold front will exit the area by early Friday morning.
A trough of low pressure will keep temperatures cool with breezy
winds through Monday. A warming trend is expected Tuesday into
Wednesday.
&&
.SHORT TERM (THU-SUN)...22/715 PM.
***UPDATE***
Post frontal trof is over Western SBA county and extends to the NE
into the center of SLO county. This trof is moving slowly to the
east. There is quite a bit of instability with this trof and it is
producing numerous showers and will likely spawn a few TSTMs over
the next couple of hours. There is only a very small chance of a
shower in the wake of this trof. The showers with this trof will
be fairly heavy and could be heavier if any TSTMs develop. The
flash flood watch for the burn areas in LA county continues due to
the threat of the TSTMs over the area this evening.
The heavier showers will make their way through SBA county and
then into VTA county and finally into and then out of LA county a
little after midnight.
Forecast is still on track for a partly cloudy day on Friday with
continued cool max temps.
Will issue a forecast update to change rain from "likely" to
"scattered showers" and to remove the wind advisory.
***From Previous Discussion***
The deep plume of moisture that has been over our area the last
two days is finally shifting east as the upper low over the
eastern Pacific and associated cold front moves onshore.
Precipitable waters are dropping pretty fast now but still
hovering in the .75-.90" range which is still above normal. What's
left now is the cold front passage and associated instability that
will come through late this afternoon and evening. The line of
showers stretching southwest from nrn SLO County is the leading
edge of the front and while there has not been a history of
thunderstorms with it yet models do indicate increasing
instability as it moves east and into the Channel Islands region
this evening. So the forecast will continue to have thunderstorm
chances through this evening, especially the southern part of the
forecast area. Given the pwats have dropped below an inch the
concern for significant flash flooding and debris flows has
lessened but not gone away completely. The watch covering the
western portion of the forecast area will still expire at 5 while
the LA County watch goes through 5 am Friday, though given the
speed at which the front is moving it's likely this watch will be
able to be cancelled as early as midnight.
So in short, the threat still exists for damaging debris flows but
now that we're in the convective part of the system any storms
that form will be very isolated and the chances of them hitting
any one area are pretty small. With the lower pwats now and storms
moving a little faster it will be more difficult, though not
impossible to reach critical rain rates for debris flows.
Additional rainfall amounts will vary from basically just trace
amounts to as much as a .50-.75" where the heavier downpours
develop.
By dawn Friday all precip should be east of the area. Temps will
remain on the cool side with some breezy northwest winds possible,
especially SLO/SB counties.
Over the weekend models continue to show a weak trough moving into
northern California with the southern edge of it brushing SLO/nrn
SB Counties. Any precip from it would be very light, less than a
tenth of an inch. Behind it Saturday night into early Sunday some
upslope snow showers are possible over the Grapevine. Farther
south just partly cloudy skies and continued cool temps.
.LONG TERM (MON-THU)...22/139 PM.
The weekend trough will evolve into a cutoff low over the Great
Basin and settle over the Colorado River on Tuesday before moving
east on Wednesday. Cool northerly flow Monday will prevent temps
from warming up too much despite some downslope warming from the
weak offshore flow. As the low moves into AZ and NM offshore
gradients will increase and possibly enough for some low end wind
advisories in Ventura/LA Counties Tuesday and Wednesday. Slight
warming expected Tuesday but better warming Wed/Thu with highs at
lower elevations in the 70s. Gradients are expected to trend
onshore Thursday afternoon so likely a little cooling at the coast
but continued warming inland. Looks like the dry pattern should
continue into next weekend.
&&
.AVIATION...23/0035Z.
At 00Z, there was no marine inversion at KLAX.
Low to moderate confidence in the current forecast. MVFR
conditions with occasional IFR conditions in heavier rainfall will
continue through 08Z, slowly improving to VFR conditions
throughout the period. There is a chance of LIFR to IFR
conditions due to ground fog between 08Z and 18Z.
KLAX...MVFR conditions will continue through 07Z, slowly
improving to VFR conditions throughout the period. There is a 20
percent chance of IFR conditions through 04Z. East winds greater
than 7 knots are likely through 05Z-08Z.
KBUR...MVFR conditions will continue through 07Z, slowly
improving to VFR conditions throughout the period. There is a 60
percent chance of IFR conditions through 02Z, lowering to 20
percent between 02Z and 04Z.
&&
.MARINE...22/810 PM.
Generally good confidence in the current forecast. For the outer
waters, Small Craft Advisory (SCA) winds will affect the entire
area tonight and Fri, and until 05Z Fri evening for PZZ670, thru
10Z late Fri night for PZZ673, and thru at least 22Z Sat
afternoon for PZZ676. Winds should come up again Sat night and
Sun, with 50%-60% chance of SCA winds Sun thru Tue.
For the inner waters N of Point Conception, there is a 20% chance
of SCA winds this evening western portion, and a 30%-40% chance
of SCA winds Sat evening and Sun evening, otherwise winds and seas
should remain below SCA thru Sun night. A 40% chance of SCA wind
gusts can be expected Mon as well.
Across the inner waters S of Point Conception, winds and seas will
remain below SCA thru Fri, then there is a 50% chance of SCA
winds Fri night thru Sun and again Sun nigh thru Mon.
Isolated thunderstorms are possible at times across the southern
waters through this evening. Brief gusty and erratic winds will
be possible near any thunderstorm.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Flash Flood Watch in effect until 5 AM PDT Friday for zones
41-46-54-88-547. (See LAXFFALOX).
PZ...Small Craft Advisory in effect until 9 PM PDT Friday for zone
670. (See LAXMWWLOX).
Small Craft Advisory in effect until 3 AM PDT Saturday for
zone 673. (See LAXMWWLOX).
Small Craft Advisory in effect until 3 PM PDT Saturday for
zone 676. (See LAXMWWLOX).
&&
.HAZARD POTENTIAL OUTLOOK (SUN-THU).
No significant hazards expected.
&&
PUBLIC...MW/Rorke
AVIATION...Hall
MARINE...Sirard
SYNOPSIS...B
weather.gov/losangelesPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
947 PM PDT THU MAR 22 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0932 PM DEBRIS FLOW 2 SE LA CONCHITA 34.33N 119.40W
03/22/2018 VENTURA CA LAW ENFORCEMENT
MUD ACROSS HWY 1 NEAR FARIA AND MONDO'S
BEACH.
&&
HALLPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
950 PM PDT THU MAR 22 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0934 PM DEBRIS FLOW 2 WNW LA CONCHITA 34.36N 119.45W
03/22/2018 VENTURA CA LAW ENFORCEMENT
MUD ACROSS SLOW LANE OF HWY 101 CAUSED
TRAFFIC COLLISION.
&&
HALLPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1020 PM PDT THU MAR 22 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1011 PM DEBRIS FLOW 5 N SANTA PAULA 34.42N 119.09W
03/22/2018 VENTURA CA LAW ENFORCEMENT
TREES, MUD, AND ROCKS ACROSS ALL LANES OF
HWY 150 NEAR STECKEL PARK.
&&
HALLPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1023 PM PDT THU MAR 22 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1020 PM DEBRIS FLOW 3 N SANTA PAULA 34.39N 119.07W
03/22/2018 VENTURA CA LAW ENFORCEMENT
MUD ACROSS HWY 150 NEAR BRIDGE RD.
&&
HALLPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1039 PM PDT THU MAR 22 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1029 PM DEBRIS FLOW 4 ESE LA CONCHITA 34.32N 119.37W
03/22/2018 VENTURA CA LAW ENFORCEMENT
MUD AND DEBRIS REPORTED.
&&
HALLPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1048 PM PDT THU MAR 22 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1047 PM HEAVY RAIN 6 NE OXNARD 34.25N 119.14W
03/22/2018 M0.64 INCH VENTURA CA MESONET
0.64 INCH IN ONE HOUR NEAR EL RIO.
&&
HALLThe Los Angeles radar (KVTX), 25 km away, was scanning. The volume nearest the first event began at 05:58 UTC.
2 flash flood. Local standard time, as filed.
California Highway Patrol reported a mud and debris flow across Highway 101, near Mussel Shoals. Heavy rain, exceeding USGS thresholds, generated the debris flow.
California Highway Patrol reported a mud and debris flow across Highway 150, near Steckel Park. Heavy rain, exceeding USGS thresholds, generated the debris flow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2018Every state in 2018This day in weather historyWarnings in California, March 2018
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: 760956, 760958.