A moist frontal system with a tap into subtropical moisture produced heavy rain for Southwest Washington January 4th and 5th. The rain resulted in flooding of the Gray's River near Rosburg and a mud or rock slide that closed part of State Route 4.
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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 PQR wrote it up.
A moist frontal system with a tap into subtropical moisture produced heavy rain for Southwest Washington January 4th and 5th. The rain resulted in flooding of the Gray's River near Rosburg and a mud or rock slide that closed part of State Route 4.
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 Portland, OR wrote its last area forecast discussion before the first event at Jan 4, 8:26 PM PST, 1 hour 4 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
825 PM PST SUN JAN 4 2015
.SYNOPSIS...A WARM FRONT WITH A SUBTROPICAL TAP BACK AROUND 145W WILL
AIM A LOT OF MOISTURE INTO WESTERN WASHINGTON AND NORTHWEST OREGON
TONIGHT AND EARLY MONDAY. THE RAIN WILL DECREASE MONDAY AFTERNOON AND
MONDAY NIGHT AS THE WARM FRONT LIFTS NORTH. 850 MB WINDS WILL PEAK
AROUND 50 KT TONIGHT...INCREASING THE MOISTURE TRANSPORT WITH THE
HEAVIEST RAIN IN SOUTHWEST WASHINGTON AND CLOSE TO THE COLUMBIA RIVER
IN NORTHWEST OREGON. AN UPPER RIDGE WILL BE OVER THE AREA TUESDAY
INTO WEDNESDAY FOR DRY WEATHER BUT AREAS OF FOG. THE NEXT FRONT NOW
LOOKS SLOWER...LIKELY HOLDING OFF UNTIL THURSDAY NIGHT AND FRIDAY.
&&
.UPDATE...FORECAST LOOKS ON TRACK WITH RAIN TOTALS ADDING UP ACROSS SW
WASHINGTON. THE HEAVIEST RAINFALL HAS BEEN NORTH OF THE PORTLAND
FORECAST AREA...BUT THERE HAS BEEN DECENT RAIN RATES FROM 0.015 TO
0.30 INCH PER HOUR ACROSS EXTREME SW WASHINGTON AND EXTREME NW
OREGON. THE HIGHEST RAINFALL MEASUREMENTS THE PAST 6 HOURS IN THE
PORTLAND FORECAST AREA HAS BEEN AT THE ASTORIA AIRPORT...WHERE 1.26
INCHES HAS BEEN MEASURED. THE SW WA COAST RIVERS ARE RISING IN
RESPONSE TO THE RAIN. THE BEST CHANCE FOR RIVER FLOODING IS FOR THE
GRAYS RIVER AT ROSBURG...BUT HAVE NOT SEEN RAPID ENOUGH RISES TO
WARRANT A WARNING YET. SNOW LEVELS OVER THE SW WASHINGTON CASCADES
ARE SLOWLY RISING AND WILL LET THE WINTER WEATHER ADVISORY EXPIRE AT
9 PM. TJ
FROM PREVIOUS SHORT TERM...850 MB WINDS AROUND 50 KT COMBINED WITH A
WARM FRONT TRANSPORTING AMPLE MOISTURE FROM A COLD FRONT WITH A
SUBSTANTIAL TROPICAL TOP OUT NEAR 145W ARE PRODUCING THE HEAVY RAIN.
SATELLITE DERIVED PWS IN THIS BAND ALONG 145W CONTINUE TO RANGE FROM
1.5 TO 2 INCHES. THE FOCUS OF THE HEAVY RAIN WILL BE SOUTHWEST
WASHINGTON AND FAR NORTHWEST OREGON...PROBABLY NOT TOO FAR SOUTH OF
THE COLUMBIA RIVER.
RAINFALL FORECASTS INDICATE THERE WILL BE SHARP RISES ON RIVERS
ESPECIALLY IN SOUTHWEST WASHINGTON. THE BEST CHANCE FOR ANY FLOODING
LOOKS TO BE ON THE GRAYS RIVER AT ROSBURG. THE COWLITZ AT KELSO MAY
ALSO APPROACH FLOOD STAGE. HAVE ISSUED A FLOOD WATCH FOR MOST OF
SOUTHWEST WASHINGTON EXCLUDING CLARK COUNTY FOR TONIGHT AND MONDAY.
RIVER FLOODING IN NORTHWEST OREGON LOOKS LESS LIKELY ESPECIALLY
SOUTH...BUT WILL NEED TO MONITOR WHETHER THE HEAVIER RAIN SLOPS SOUTH
OF THE COLUMBIA RIVER LONG ENOUGH TO CAUSE PROBLEMS.
THE STRONG 850 MB WINDS WILL ALSO LEAD TO SOME WINDY CONDITIONS ALONG
THE COAST...STRONGEST ALONG THE SOUTH WASHINGTON AND NORTH OREGON
COASTAL BEACHES AND HEADLANDS WHERE GUSTS TO 55 MPH ARE POSSIBLE
TONIGHT.
THE WARM FRONT LIFTS NORTH OF OUR FORECAST AREA DURING THE DAY ON
MONDAY...WITH RAIN DECREASING BY AFTERNOON...AND MOSTLY ENDING MONDAY
NIGHT. WE WILL THEN BE IN THE WARM SECTOR WITH DECREASING CLOUDS
MONDAY NIGHT AND TUESDAY...BUT WITH THE MOIST GROUND EXPECT AREAS OF
FOG TO DEVELOP MONDAY NIGHT AND CONTINUE INTO TUESDAY. LIGHT
GRADIENTS ON TUESDAY SUGGEST THE FOG AND LOW CLOUDS WILL BE SLOW TO
CLEAR IF THEY DO CLEAR AT ALL. NOT MUCH CHANGE IS THEN EXPECTED
WEDNESDAY SA COMPARED TO TUESDAY WITH MORE AREAS OF FOG UNDER A DRY
UPPER RIDGE AND A CONTINUED MILD AIR MASS. TOLLESON
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...WEDNESDAY
NIGHT THROUGH SUNDAY...THE DRY...STABLE AND SOMEWHAT STAGNANT PATTERN
ENDING THE SHORT TERM PERIOD APPEARS IT WILL EXTEND INTO THURSDAY AS
THE MODELS HAVE SLOWED DOWN THE NEXT SYSTEM...WHICH NOW LOOKS LIKE IT
WILL ARRIVE MAINLY ON THURSDAY NIGHT AND FINISH MOVING THROUGH
SOUTHWEST WASHINGTON AND NORTHWEST OREGON ON FRIDAY. THIS SYSTEM IS
RELATIVELY WEAK AND STILL ON THE MILD SIDE. ANOTHER RELATIVELY WEAK
SYSTEM LOOKS TO START TO EDGE IN FROM THE WEST AND NORTHWEST DURING
THE LATTER PART OF NEXT WEEKEND. TOLLESON
&&
.AVIATION...WIDESPREAD MVFR CIGS ACROSS THE FORECAST AREA THIS
EVENING. RAIN WILL CONTINUE TO INCREASE TONIGHT...ESPECIALLY
ACROSS SW WASHINGTON AND EXTREME NW OREGON. THE COASTAL TERMINALS
WILL LIKELY SEE PERIODS OF IFR VSBYS IN RAIN AND GUSTY S WINDS
WILL CONTINUE OVERNIGHT. ACROSS THE INTERIOR...EXPECT
PREDOMINATELY MVFR WITH A FEW LOCAL POCKETS OF IFR POSSIBLE.
MOUNTAINS
AND HIGHER TERRAIN TO BE OBSCURED IN RAIN/FOG THROUGH MONDAY. RAIN
WILL TAPER OFF MONDAY AS FRONTAL BOUNDARY LIFTS NORTH...AND SOME
IMPROVEMENT TO HIGHER MVFR OR BETTER LIKELY BY AROUND MIDDAY MON.
KPDX AND APPROACHES...MVFR PREVAILS AT THE TERMINAL THIS EVENING.
GUSTY S WINDS WILL INCREASE AND PERSIST OVERNIGHT...WHICH MAY
SERVE TO BRIEFLY IMPROVE CIGS TO HIGHER MVFR OR PERHAPS EVEN VFR
THROUGH ABOUT 09Z MON. HOWEVER...AS RAIN INCREASES THROUGH THE
OVERNIGHT AND WINDS GRADUALLY EASE...EXPECT SOLID MVFR FOR MOST OF
THE PERIOD. RAIN WILL BEGIN TO TAPER BY EARLY AFTERNOON WITH SOME
IMPROVEMENT IN CIGS...THOUGH GOOD CHANCE THAT FOG DEVELOPS WITH
THIS CLEARING MON NIGHT INTO TUE. CULLEN
&&
.MARINE...WIDESPREAD GALE FORCE GUSTS CONTINUE OVER THE WATERS
THIS EVENING...WITH BUOY 46029 REPORTING A PEAK GUST OF 39 KT LAST
HOUR. THESE WINDS ARE EXPECTED TO CONTINUE OVERNIGHT...EASING A
BIT AFTER MIDNIGHT. A MORE DRAMATIC DROP OFF IN WIND SPEED LIKELY
WILL OCCUR EARLY MONDAY MORNING. WILL MAINTAIN CURRENT GALE
WARNING THROUGH 9 AM...THOUGH WOULD NOT BE SURPRISED TO SEE GUSTS
BEGIN TO DROP BELOW GALE CRITERIA FROM SOUTH TO NORTH STARTING
AROUND 5 OR 6 AM.
THESE STRONG WINDS HAVE PUSHED SEAS UP TO 15 FEET IN THE NORTH
AND STRONGLY DOMINATED BY WIND WAVE COMPONENT...RESULTING IN VERY
CHOPPY CONDITIONS. SEAS WILL LIKELY PEAK OVERNIGHT IN THE 14 TO 16
FT RANGE IN THE NORTH...BUT CLOSER TO 12 TO 14 FT FOR THE CENTRAL
OREGON WATERS...BEFORE GRADUALLY SUBSIDING BELOW 10 FT BY MONDAY
EVENING.
EXPECT MUCH CALMER WIND CONDITIONS...GENERALLY BELOW 15 KT...FOR
MUCH OF THE NEXT WEEK AS REBUILDING SURFACE HIGH PRESSURE WILL
PERSIST FROM MONDAY EVENING THROUGH MUCH OF THE WEEK. SEAS ALSO
LOOK TO REMAIN BELOW 10 FT THROUGH MUCH OF THE WEEK. FORECAST
MODELS CONTINUE TO SUGGEST THE NEXT COLD FRONT WILL NOT APPROACH
THE WATERS UNTIL AT LEAST LATE THURSDAY...AND THIS WEAKENING FRONT
MAY BRING A CHANCE OF ADVISORY LEVEL WINDS AND/OR SEAS. CULLEN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR I-5 CORRIDOR IN
COWLITZ COUNTY-SOUTH WASHINGTON CASCADE FOOTHILLS-SOUTH
WASHINGTON CASCADES-SOUTH WASHINGTON COAST-WILLAPA HILLS.
WINTER WEATHER ADVISORY UNTIL 9 PM PST THIS EVENING FOR SOUTH
WASHINGTON CASCADES.
PZ...GALE WARNING UNTIL 7 AM PST MONDAY FOR COASTAL WATERS FROM CAPE
SHOALWATER WA TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 8 PM
PST MONDAY.
&&
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.The national radar mosaic for the moment the first event began.
2 flood, 1 heavy rain. Local standard time, as filed.
The Washington Department of Transportation reported Westbound State Route 4 was closed at mile post 21 due to a rock or mud slide resulting from heavy rain. The rain gauge at nearby KM Mountain measured 2 inches of rain in the 6 hour period leading up to the slide.
Grays River near Rosburg reached flood stage of 12 feet at 1205 AM on January 5th, and crested around 15.4 feet at 815 AM. The river fell below flood stage around 1030 PM.
The Naselle River near Naselle reached flood stage of 15.5 feet at 410 AM on January 5th. The river crested at the major flood stage of 17 feet around 745 AM before dropping below flood stage at 1150 AM.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2015Every state in 2015This day in weather historyWarnings in Washington, January 2015
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: 552373, 552365, 552366.