Flooding in Washington, February 21, 2017

Name: Flooding in Washington, February 21, 2017
Start: 2017-02-21T14:43
End: 2017-02-21T20:39
Location: Washington

February 21, 2017 · NWS PDT · 3 events in 3 counties and zones

Rapid melting of low elevation snow pack with heavy rain cause flooding across portions of southeast Washington.

Where it happened

Every event with a place to put it. 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

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The toll

Deaths: 0
Injuries: 0
Property damage: $3.0 million
Crop damage: None recorded
Events: 3

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 PDT wrote it up.

Rapid melting of low elevation snow pack with heavy rain cause flooding across portions of southeast Washington.

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 Pendleton, OR wrote its last area forecast discussion before the first event at Feb 21, 2:30 PM PST, 13 minutes earlier.

Area forecast discussion, Feb 21, 2:30 PM PST, 13 minutes before

Area Forecast Discussion
National Weather Service Pendleton OR
230 PM PST Tue Feb 21 2017

.SHORT TERM...Tonight through Thursday night...A storm system
continues to track across the CWA late this afternoon and evening.
This system is bringing periods of moderate rain and higher
elevation snow to much of the area. Snow levels are hovering around
1500 feet this evening. An urban and small stream flood advisory is
in effect for portions of Morrow, Umatilla, Benton, Franklin, Walla
Walla and Columbia Counties...and this will likely be extended into
this evening as rain continues to impact this area. Numerous reports
of road closure and washouts have been received...mainly in Benton
and Franklin Counties thus far. Colder air aloft is filtering into
the region and will continue to do through the overnight hours.
Moderate snow is already falling across the northern Blue Mountains,
including Meacham and Tollgate. Considering the strong, moist
upslope flow is progged to continue through at least the first half
of the overnight decided to issue a winter weather advisory for this
area...with a general 3-7 inches of snow expected by Wednesday
morning...especially above 3500 feet. This snow will impact
interstate 84 over the Blue Mountains and highway 204 near Tollgate.
The precipitation should taper off and end in the lower columbia
basin and surrounding areas by late this evening...with generally
just lingering mountain showers expected overnight. On Wednesday a
cold upper level trough will remain in place over the CWA, with
850mb temps between -2 to -4C for most locations. Any precipitation
will be light, and mainly confined to the mountain and upper
foothill zones. Snow levels will be low through the day...around
1200-1500 feet. High temperatures will only be in the mid 30s to
lower 40s...except upper 20s and 30s mountains. A stronger upper
level disturbance will pass by along the Oregon Coast Wednesday
night...however this system seems to be lacking any true deep
moisture. Therefore, just continued with chance PoPs for snow
showers...mainly for the western half of the forecast area. As the
upper level cold pool moves over the area on Thursday there could be
a higher chance for snow and lower elevation rain/snow showers. This
will be due to increasing atmospheric instabiity. After sunset
Thursday night, conditions should gradually dry out as the system
moves east and the instability decreases. At this time, any snow
accumulations look to be limited to above 1500 feet and mostly in
the mountains with this system.

.LONG TERM...Friday through Sunday afternoon...Friday and Friday
night snow levels around 500-1000 feet through Friday. A strong
mid/upper level shortwave dives south out of British Columbia on the
western flank of a longwave trough over the Pacific Northwest. The
shortwave triggers strong deepening of the trough with the main
energy developing offshore and evolving into a strong mid/upper
level closed low that digs southward offshore and then moves inland
into California. The track of the low means that the main dynamic
lift associated with this system will miss eastern sections of WA/OR
and thus result in only a slight chance of snow in the mountains of
central and NE Oregon. Another upstream mid/upper level shortwave
moves SE along coastal British Columbia on Saturday/Saturday night
and moves into interior Pacific Northwest by daybreak Sunday
spreading moisture east of the Cascades for a chance of mainly snow
through Sunday afternoon.  Polan

.Sunday Night through Tuesday...GFS/ECMWF in general agreement
bringing a trough across the Pacific Northwest Sunday Night, with
the bulk of the lift digging across southern OR/northern CA by
Monday. Thus, will concentrate the highest PoPs across the OR zones,
with high end chance to likely PoPs for the NE OR mtns in favored
upslope flow. Areas to the north will experience mainly slight
chance to low end PoPs. Snow levels will be low enough for precip to
be snow for most areas, with some rain mixed in for the lowest
elevations of the Basin/Gorge. Additional shortwaves in mainly NW
flow will prevail Monday Night/Tuesday. With weaker lift present,
will keep PoPs slight chance to low end chance category, with mainly
dry conditions for the Columbia Basin. Snow levels will rise
slightly by Tuesday with mainly rain for the Foothills and Gorge.
Temperatures 5-10 degrees below normal will generally prevail.

&&

.AVIATION...00Z TAFs...LIFR/IFR at KPDT and KALW for a few more
hours before conditions improve. Otherwise, VFR conditions are
expected over the next 24 hours. Winds will be 5-10 kts over the
next 24 hours.  Polan

&&

.HYDROLOGY...Periods of moderate rain are continuing across parts of
south central, southeast Washington, and northeast Oregon. An areal
flood advisory/warning remains in effect for parts of this area
through at least this evening. Additional rainfall amounts of up to
three quarters of an inch will be possible, especially along the
Blue Mountain foothills zones. These rainfall amounts will cause
increased runoff, ponding on area roadways and low lying areas.
Localized washouts and undermining of roadways is likely. Be sure to
follow all road closures and never drive around flood barriers.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  30  40  26  40 /  60  10  10  30
ALW  32  38  27  38 /  70  20  10  30
PSC  29  39  26  39 /  20  10  10  10
YKM  26  39  21  39 /  10  10  10  10
HRI  30  38  25  38 /  20  10  10  20
ELN  26  35  18  34 /  10  10  10  20
RDM  24  37  20  38 /  40  30  20  30
LGD  29  39  23  37 /  50  20  20  30
GCD  24  38  21  38 /  60  30  20  30
DLS  33  36  29  38 /  10  20  20  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 4 AM PST Wednesday for ORZ502.

WA...Winter Weather Advisory until 4 AM PST Wednesday for WAZ030.

&&

77/99/99/80

In the hours before

Local storm report, Feb 21, 10:44 AM PST, 3 hours 59 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
1044 AM PST TUE FEB 21 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1110 AM     NON-TSTM WND GST CONDON                  45.24N 120.18W
02/20/2017  E60 MPH          GILLIAM            OR   COCORAHS

            OBSERVER REPORTED WINDS AROUND 60 MPH IN THE CONDON AREA.
            SUBMITTIED VIA FB.

&&

RQB

Local storm report, Feb 21, 10:50 AM PST, 3 hours 53 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
1050 AM PST TUE FEB 21 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1148 AM     NON-TSTM WND GST 8 NNW CLARNO            45.03N 120.54W
02/20/2017  M69 MPH          WASCO              OR   MESONET

            THE NORTHPOLE RIDGE RAWS REPORTED 43 MPH SUSTAINED WINDS
            WITH GUSTS TO 69 MPH. ELEVATION 3480.

&&

RQB

Local storm report, Feb 21, 10:58 AM PST, 3 hours 45 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
1058 AM PST TUE FEB 21 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1159 AM     NON-TSTM WND GST 6 W CONDON              45.24N 120.30W
02/20/2017  M63 MPH          GILLIAM            OR   MESONET

            THE CWOP STATION 6 MILES WEST OF CONDON RECORDED A WIND
            GUST TO 63 MPH.

&&

RQB

Local storm report, Feb 21, 11:07 AM PST, 3 hours 36 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
1107 AM PST TUE FEB 21 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1155 PM     NON-TSTM WND GST LEXINGTON               45.45N 119.69W
02/20/2017  M61.00 MPH       MORROW             OR   AWOS

            THE AWOS AT THE LEXINGTON AIRPORT RECORDED SUSTAINED
            WINDS ABOVE 40 MPH WITH PEAK WINDS OF 61 MPH THROUGH THE
            LATE MORNING AND EARLY AFTERNOON.

&&

RQB

Local storm report, Feb 21, 11:09 AM PST, 3 hours 34 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
1109 AM PST TUE FEB 21 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0106 PM     NON-TSTM WND GST HEPPNER                 45.35N 119.55W
02/20/2017  M60 MPH          MORROW             OR   AWOS

            THE AWOS AT HEPPNER RECORDED A GUST TO 60 MPH.

&&

RQB

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

3 flood. Local standard time, as filed.

Flood, Benton

When: February 21, 2:43 PM PST to 8:39 PM PST
Where: Benton County, 1.6 mi WNW of Badger to 4.4 mi SW of Kiona
Cause: Heavy Rain / Snow Melt
Reported by: Emergency Manager
Coordinates: 46.239, -119.381

Mild temperatures February 9 -13 allowed an initial snow melt and heavy rain caused rapid melting and increased runoff across Benton county. This area had a snowpack of 5-10 inches on February 15, with much of it melted by February 21. Rain amounts of 0.50 to 0.75 were seen on February 16 and temperatures remained above freezing through February 22 with additional rain amounts of 0.50 to 1.00 inches on February 21-22. Numerous county roads had washouts, erosion, slides and undermining.

Flood, Franklin

When: February 21, 2:43 PM PST to 8:39 PM PST
Where: Franklin County, 1.39 mi NNW of Sagehill to 10.47 mi NW of (Psc)tri-Cities Arpt
Cause: Heavy Rain / Snow Melt
Property damage: $3.0 million
Reported by: Emergency Manager
Coordinates: 46.699, -119.280

Mild temperatures February 9 -13 allowed an initial snow melt and heavy rain caused rapid melting and increased runoff across Franklin County. This area had a snow pack of 5-10 inches on February 15, with much of it melted by February 21. Rain amounts of 0.50 to 0.75 were seen on February 16 and temperatures remained above freezing through February 22 with additional rain amounts of 0.50 to 1.00 inches on February 21-22. Numerous county roads had washouts, erosion, slides and undermining. In Connell, the ground was saturated with the melting snow pack and heavy rain to the north of town ( Lind, Washington had about 1 inch of rain over the 2 day period, February 15 and 16). The Esquatzel Coulee at Connell was over-topped with water and ice running through streets. A large sinkhole/erosion area was noted near Eltopia. Damage is estimated at 3 million dollars for Franklin County, for mainly roads.

Flood, Walla Walla

When: February 21, 2:43 PM PST to 8:39 PM PST
Where: Walla Walla County, 1.01 mi NE of Chew to 1.11 mi S of Scott
Cause: Heavy Rain / Snow Melt
Property damage: $10,000
Reported by: Emergency Manager
Coordinates: 46.582, -118.258

Mild temperatures February 9 -13 allowed an initial snow melt and heavy rain caused rapid melting and increased runoff across northern Walla Walla County. This area had a snow pack of 5-10 inches on February 15, with much of it melted by February 21. Rain amounts of 0.50 to 0.75 were seen on February 16 and temperatures remained above freezing through February 22 with additional rain amounts of 0.50 to 1.00 inches on February 21-22. Numerous county roads had washouts, erosion, slides and undermining.

What these are

Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

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

The same day elsewhere

Every storm in Washington in 2017 Every state in 2017 This day in weather history Warnings in Washington, February 2017

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: 683393, 683400, 683405.