A winter storm with copious moisture dumped 1 to locally 2+ feet of snow over the eastern mountains and valleys February 4th and 5th. This was the precursor to significant flooding that occurred later in the week when the snow melted due a warm-up and heavy rains.
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 PDT wrote it up.
A winter storm with copious moisture dumped 1 to locally 2+ feet of snow over the eastern mountains and valleys February 4th and 5th. This was the precursor to significant flooding that occurred later in the week when the snow melted due a warm-up and heavy rains.
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 4, 2:00 PM PST, 2 hours earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
200 PM PST Tue Feb 4 2020
.SHORT TERM...Tonight through Friday...A northwest flow is over the
region as an upper level trough moves to the east and an upper level
ridge over the eastern Pacific approaches. A system riding over the
ridge will move into the forecast area overnight and Wednesday as a
warm front. Snow levels will initially be low overnight but then
begin to rise late tonight and through Wednesday becoming 6000 to
7000 feet Wednesday night. There will be some significant snow
accumulations that occur overnight and into Wednesday over the
eastern mountains and WA CAscades before precipitation changes to
rain. Several winter weather advisories and warnings go into effect
overnight. The warm front will usher in much warmer air for
Wednesday and Thursday along with some breezy to windy conditions.
The continued northwest flow under the warmer conditions mean
increased snowmelt and runoff occurring in the mountains leading to
rising streams and rivers over the coming days. Precipitation will
begin to dwindle Friday as the moist northwest flow subsides.
.LONG TERM...Friday night through Tuesday...Northwesterly flow
Friday with lingering mountain showers ending with transient ridging
moves over the region. Dry period will be brief as a vigorous upper
low/trough drop south and east across the region Friday night into
Saturday, bringing a good burst of mountain snow and a chance of low
elevation rain. Expect precip to end north to south Saturday night
with a few lingering showers ending across central/northeast OR
mountains on Sunday. Drier and cooler northerly flow then expected
into Monday as the upper low drops south and cuts off over southern
CA. Another upper low/trough expected to impact the region Monday
night into Tuesday and will bring another shot of mountain snow.
Overall, atmosphere will be cooler with this system, so could see
chance of rain mixing with, or changing over to snow for the lower
elevations. Cooling pattern through the period with the passage of
multiple troughs/fronts. More seasonable temps with highs in the
40s. Locally breezy winds with each trough/frontal passage as well,
especially with the weekend system.
&&
.AVIATION...00Z TAFs...A system moving through will spread mountain
snow and bring a chance of snow at the terminals, starting between
23Z to 03Z, eventually changing over to rain overnight into
tomorrow. MVFR or lower CIGs/VIS possible and mountain obscuration
likely. Winds 5-15kts through most of tonight, becoming 15-25kts
with higher gusts tomorrow.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 33 52 46 59 / 90 90 50 20
ALW 32 51 45 58 / 100 100 60 40
PSC 35 52 46 61 / 50 40 10 10
YKM 30 52 38 61 / 20 30 20 30
HRI 35 53 47 61 / 50 50 10 10
ELN 30 48 38 54 / 40 40 20 60
RDM 32 49 38 54 / 40 30 20 10
LGD 28 42 41 50 / 100 100 90 50
GCD 29 47 41 51 / 90 90 70 30
DLS 35 52 45 56 / 60 50 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory from 6 PM this evening to 6 AM PST
Wednesday for ORZ507.
Winter Storm Warning until 4 PM PST Wednesday for ORZ502-503.
Winter Weather Advisory from 6 PM this evening to 10 AM PST
Wednesday for ORZ505.
Winter Storm Warning from 7 PM this evening to 10 AM PST
Wednesday for ORZ049.
Winter Storm Warning from 10 PM this evening to 4 PM PST
Wednesday for ORZ050.
WA...Winter Weather Advisory from 6 PM this evening to 6 AM PST
Wednesday for WAZ029.
Winter Storm Warning until 4 PM PST Wednesday for WAZ030.
Winter Weather Advisory until 7 AM PST Wednesday for WAZ520.
&&
91/84/84The national radar mosaic for the moment the first event began.
5 heavy snow. Local standard time, as filed.
Sixteen inches of snow at Milkshakes Snotel and 13 at Emigrant Springs Snotel.
Twelve inches of snow in Granite and 4N Ukiah.
Seven inches of snow in Mount Vernon 10 inches 6 east of John Day.
New snow of 17.5 inches 5 NNE La Grande and 26.5 inches 1 NNW La Grande. Widespread snow amounts above 10 inches.
Eight inches of snow in Wallowa and 6 inches of snow 3N of Joseph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2020Every state in 2020This day in weather historyWarnings in Oregon, February 2020
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: 870201, 870202, 870203, 870199, 870197.