Debris Flow and Strong Wind in California, April 16 to 17, 2006

Name: Debris Flow and Strong Wind in California, April 16 to 17, 2006
Start: 2006-04-16T11:00
End: 2006-04-17T13:00
Location: California

April 16 to 17, 2006 · NWS HNX · 4 events in 4 counties and zones

Sierra Nevada, heavy rain in the Sierra Foothills, and windy conditions to the Kern Mountains and Indian Wells Valley. In the mountains Tuolomne received 12" additional snow and Tenaya Lake 18" in 24 hours.

The toll

Deaths: 0
Injuries: 0
Property damage: $2,000
Crop damage: None recorded
Events: 4

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 HNX wrote it up.

Another weather system swept through Central California on the 16th bringing more snow to the higher terrain of the S.Sierra Nevada, heavy rain in the Sierra Foothills, and windy conditions to the Kern Mountains and Indian Wells Valley. In the mountains Tuolomne received 12" additional snow and Tenaya Lake 18" in 24 hours. Black Cap Basin 7" and Sierra Summit Ski Resort got an additional 7" in 12 hours overnight. Encouraged by continued rainfall, the rockslide continues onto Highway 140 in Mariposa County, 6.3 miles WSW of Savages Trading Post on State Highway 140 continuing to close access into Yosemite National Park through that all-weather highway.

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 Hanford, CA wrote its last area forecast discussion before the first event at Apr 16, 8:49 AM PST, 2 hours 11 minutes earlier.

Area forecast discussion, Apr 16, 8:49 AM PST, 2 hours 11 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
949 AM PDT SUN APR 16 2006

.UPDATE...FRONTAL SYSTEM IS MAKING ONLY VERY SLOW PROGRESS SOUTHWARD
WITH MAIN PRECIPITATION AREA REMAINING NORTH OF THE DISTRICT. JUST
SOME TRACE AMOUNTS HAVE BEEN RECORDED OVER EXTREME NORTHERN PORTIONS
OF THE VALLEY ZONES...THOUGH SOME MODERATE PRECIP IS NOW OCCURRING
IN THE YOSEMITE VICINITY. ENERGY DIVING INTO THE BASE OF THE TROUGH
IS EXPECTED TO GIVE THE FRONTAL BAND A NUDGE SOUTHWARD AND PRECIP
CONTINUES TO LOOK LIKELY FOR THE NORTHERN HALF OF THE DISTRICT
TODAY. SOUTHERN PORTIONS SHOULD ESCAPE THE BRUNT OF THE
PRECIP...THOUGH OROGRAPHICS WILL FAVOR SOME PRECIPITATION IN THE
SOUTHERN SIERRA ZONES. ONSHORE SURFACE PRESSURE GRADIENTS ARE
CURRENTLY UNIMPRESSIVE BUT EXPECTED TO TIGHTEN UP THROUGH TOMORROW
AFTERNOON. WITH UPPER JET SUPPORT...ADVISORY LEVEL WINDS ARE
POSSIBLE IN THE KERN DESERT AND MOUNTAINS THIS AFTERNOON THROUGH
TOMORROW AFTERNOON AND THE ADVISORY BEGINNING THIS AFTERNOON LOOKS
OK. JUST LINGERING SHOWERS IN THE SIERRA TOMORROW MORNING AS THE
TROUGH AXIS MOVES EAST...THEN WARMING TUESDAY AS A RIDGE BEGINS TO
BUILD IN.

PREVIOUS DISCUSSION...

.SHORT TERM...FOR THE CENTRAL CALIFORNIA INTERIOR...A BAROCLINIC
ZONE CURRENTLY STALLED OVER NORTHERN CA WILL GAIN SOUTHWARD MOMENTUM
TODAY AND SLIDE INTO CENTRAL CA BY LATE THIS MORNING. A 120-KT JET
CURRENTLY LOCATED AT 45N/140W WILL CARVE AROUND THE BASE OF AN E/PAC
UPPER TROUGH, PROVIDING THE DRIVING FORCE TO INITIATE THE FRONTS
SOUTHWARD PUSH. AS THE COLD FRONT DROPS INTO OUR CWA TODAY, ON-SHORE
PRESSURE GRADIENTS WILL INCREASE. STRONG UPPER LEVEL WINDS
ASSOCIATED WITH THE DIVING JET WILL ALIGN WITH SURFACE GRADIENTS,
AND MODERATE/STRONG SUBSIDENCE OVER THE KERN MOUNTAINS/DESERT WILL
HELP MIX THESE STRONG WINDS ALOFT DOWN TO THE SURFACE. WILL GO AHEAD
AND ISSUE A WIND ADVISORY FOR ZNS 95/98/99 FOR 24 HOURS BEGINNING AT
200 PM THIS AFTERNOON.

ALSO ACCOMPANYING THE FRONT, RAIN AND HIGHER ELEVATION SNOW WILL
SPREAD SOUTHWARD TODAY AND TONIGHT, BUT PRECIPITATION AMOUNTS IN THE
VALLEY WILL PROBABLY BE LESS THAN IMPRESSIVE. ON THE OTHER HAND,
OROGRAPHICS WILL HELP ENHANCE PRECIP OVER THE HIGHER TERRAIN,
AND THE SNOW ADVISORY FOR THE S. SIERRA STILL LOOKS ON TRACK.
RESIDUAL MOISTURE AND STRONG UPSLOPE FLOW WILL KEEP A SLIGHT RISK OF
SHOWERS GOING FOR THE MOUNTAINS ON MONDAY. IN ADDITION, CLOUDS
BANKED UP ALONG THE FOOTHILLS AND NORTH/WEST FACING SLOPES OF THE
TEHACHAPIS COULD MAKE FOR ONE MORE GLOOMY DAY. OTHERWISE, IMPROVING
WEATHER CONDITIONS CAN BE EXPECTED MONDAY-TUESDAY AS A RIDGE OF
HIGH PRESSURE BEGINS BUILDING OVER THE WEST COAST. TEMPERATURES
WILL UNDERGO A WARMING TREND THIS WEEK, THOUGH A MINOR RIPPLE
TRAVERSING THE UPPER LEVEL FLOW WILL LIKELY PREVENT US FROM REACHING
OUR SEASONAL NORMS ON TUESDAY.

.LONG TERM...FOR TUESDAY NIGHT THROUGH SATURDAY...EXPECT DRIER AND
WARMER WEATHER THROUGH MID WEEK AS RIDGING OFF THE WEST COAST SHIFTS
ONSHORE OVER THE STATE. THE RIDGE WILL CONTINUE TO GRADUALLY SHIFT
EAST WHILE TEMPERATURES CLIMB TO NEAR OR SLIGHTLY ABOVE NORMAL.
MOST PROGS SHOW A WEAK UPPER TROUGH REACHING THE AREA WEDNESDAY.
HOWEVER DO NOT EXPECT MUCH IN SENSIBLE WEATHER EXCEPT FOR AN
INCREASE IN CLOUDINESS. A MUCH DEEPER UPPER TROUGH WILL NEAR THE
WEST COAST ON THURSDAY. THE EURO HAS BEEN CONSISTENT IN DEVELOPING
A CUT OFF UPPER LOW FRIDAY OFF THE CENTRAL CALIFORNIA COAST AND THE
GFS AND NOGAPS TRENDING TOWARDS THE ECMWF SOLUTION. THIS SCENARIO
WILL RESULT IN A SLOW MOVING STORM SYSTEM AND PROVIDE A RISK OF
PRECIPITATION ACROSS CENTRAL AND SOUTH CALIFORNIA THROUGH SATURDAY.
THE PRECIPITATION MAY BECOME CONVECTIVE WITH SHOWERS AND AFTERNOON
THUNDER SATURDAY AS BOTH GFS AND EURO PROG THE LOW INLAND OVER
CALIFORNIA. EXPECT BELOW NORMAL TEMPERATURES TO RETURN ONCE AGAIN
AS THE TROUGH NEARS THE WEST COAST AT THE END OF THE WEEK.

&&

.AVIATION...A STORM SYSTEM WILL MOVE INTO THE REGION TODAY BRINGING
STRONG WINDS OVER THE SIERRA AND KERN COUNTY MOUNTAINS AND DESERTS
BY 21Z THIS AFTERNOON. A FRONT WILL PUSH SOUTH BRINGING AREAS OF
MVFR VISIBILITIES IN RAIN BY 19Z ACROSS THE CENTRAL VALLEY AND TO
THE SOUTH VALLEY BY 22Z. LOW CLOUDS WILL PROVIDE MOUNTAINS
OBSCURATION FOR MUCH OF THE PERIOD ACROSS THE SIERRA AND
TEHACHAPIS.  FOR SPECIFIC DETAILS...PLEASE REFER TO TAFS FOR
KMCE...KFAT AND KBFL.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...SNOW ADVISORY FOR THE SOUTHERN
     SIERRA NEVADA FROM YOSEMITE TO KINGS CANYON ABOVE 7000 FEET
     FROM NOON TODAY TO 4 AM MONDAY MORNING.
  ...WIND ADVISORY FOR THE KERN COUNTY MOUNTAINS AND DESERT FROM 200
     PM THIS AFTERNOON TO 200 PM MONDAY.

&&

WWW.WEATHER.GOV/HANFORD /USE ALL LOWER CASE/

JEB/MYERS/MV

Hazardous weather outlook, Apr 16, 4:00 AM PST, 7 hours before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
500 AM PDT SUN APR 16 2006

CAZ089>094-097-171200-
WEST CENTRAL SAN JOAQUIN VALLEY-EAST CENTRAL SAN JOAQUIN VALLEY-
SOUTHWESTERN SAN JOAQUIN VALLEY-SOUTHEASTERN SAN JOAQUIN VALLEY-
MARIPOSA MADERA AND FRESNO COUNTY FOOTHILLS-TULARE COUNTY FOOTHILLS-
TULARE COUNTY MOUNTAINS-
500 AM PDT SUN APR 16 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE CENTRAL AND SOUTHERN SAN
JOAQUIN VALLEY...THE FOOTHILLS OF THE SOUTHERN SIERRA NEVADA...AND
THE TULARE COUNTY MOUNTAINS.

.DAY ONE...TODAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THE SAN JOAQUIN VALLEY NATIONAL WEATHER SERVICE
OFFICE.

CAZ095-098-099-171200-
KERN COUNTY MOUNTAINS-INDIAN WELLS VALLEY-
SOUTHEASTERN KERN COUNTY DESERT-
500 AM PDT SUN APR 16 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE KERN COUNTY MOUNTAINS AND
DESERT.

.DAY ONE...TODAY

A WIND ADVISORY WILL BE IN EFFECT FROM 2 PM THIS AFTERNOON TO 2 PM
PDT MONDAY.  PLEASE REFER TO THE LATEST WEATHER MESSAGE /WWUS76
KHNX...OR SFONPWHNX/ FOR FURTHER DETAILS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THE WIND ADVISORY WILL REMAIN IN EFFECT UNTIL 2 PM PDT MONDAY.

OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THE SAN JOAQUIN VALLEY NATIONAL WEATHER SERVICE
OFFICE.

CAZ096-171200-
SIERRA NEVADA FROM YOSEMITE TO KINGS CANYON-
500 AM PDT SUN APR 16 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE SOUTHERN SIERRA NEVADA
FROM YOSEMITE TO KINGS CANYON.

.DAY ONE...TODAY

A SNOW ADVISORY WILL BE IN EFFECT FROM NOON TO 4 AM PDT MONDAY.
PLEASE REFER TO THE LATEST WINTER WEATHER MESSAGE /WWUS46 KHNX...
OR SFOWSWHNX/ FOR FURTHER DETAILS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THE SNOW ADVISORY WILL REMAIN IN EFFECT UNTIL 4 AM PDT MONDAY.

OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THE SAN JOAQUIN VALLEY NATIONAL WEATHER SERVICE
OFFICE.

MORSE

Event by event

2 strong wind, 1 winter weather, 1 debris flow. Local standard time, as filed.

Winter Weather, S Sierra Mtns

When: April 16, 11:00 AM PST to April 17, 2:00 AM PST
Where: S Sierra Mtns forecast zone
Reported by: TRAINED SPOTTER

Strong Wind, Kern Cty Mtns

When: April 16, 11:55 AM PST to April 17, 1:00 PM PST
Where: Kern Cty Mtns forecast zone
Measured: 46 kt (53 mph) measured gust
Property damage: $1,000
Reported by: AWOS,ASOS,MESONET,ETC

Strong Wind, Indian Wells Vly

When: April 16, 4:10 PM PST to April 17, 1:00 PM PST
Where: Indian Wells Vly forecast zone
Measured: 46 kt (53 mph) measured gust
Property damage: $1,000
Reported by: AWOS,ASOS,MESONET,ETC

Debris Flow, S Sierra Foothills

When: April 16, 6:01 PM PST to April 17, 3:00 AM PST
Where: S Sierra Foothills forecast zone
Reported by: LAW ENFORCEMENT

What these are

Winter Weather: Snow, sleet or freezing rain below warning levels that still caused disruption, damage or casualties.
Strong Wind: Non-thunderstorm winds below high wind criteria that nonetheless caused damage or casualties.
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 2006 Every state in 2006 This day in weather history Warnings in California, April 2006

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: 5502000, 5502001, 5502002, 5502003.