Heavy Snow was reported over the mountains and High Valleys with 6 to 12 inches of accumulation reported in many locations.
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.
Heavy Snow was reported over the mountains and High Valleys with 6 to 12 inches of accumulation reported in many 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 Pendleton, OR wrote its last area forecast discussion before the first event at Jan 10, 9:36 AM PST, 24 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
936 AM PST Fri Jan 10 2020
Updated Aviation Discussion
SHORT TERM...Upper low offshore is pushing a front through the
Pacific northwest today. Satellite showing fairly solid cloud
cover across the forecast area. The airmass is cold with low snow
levels. Dew points are also allowing for evaporational cooling.
Will likely have some low elevation snow this morning then mixed
rain and snow for the afternoon. The mid and higher elevations
will have all snow. Good westerly onshore flow will result in
heavy snow for the Cascades. Surface gradients and winds aloft
should give an increase in winds this afternoon after frontal
passage. Heavy snow will continue tonight for the Cascades with
cold onshore flow associated with the upper low. 94
AVIATION...18Z TAFs... A system currently moving through the
region is bringing mountain snow and lower elevation rain.
Currently, radar shows ALW/PDT/PSC with light rain echos within
the vicinity, and PSC currently reporting light rain. Expect MVFR
conditions to develop later this morning as ceilings and vsby
lower over the region, and periodic precip occurring after 01Z at
all sites. Winds will be breezy with southerly 10-20kts at
PDT/RDM/BDN/ALW/PSC through the period. Lawhorn/82
PREV DISCUSSION... /issued 157 AM PST Fri Jan 10 2020/
SHORT TERM...Today through Sunday...A series of Pacific weather
systems will move into the northwest bringing mountain snow and
mostly low elevation rain. The snow will become heavy at times in
the Cascades and the eastern/northeast mountains of Oregon and
southeast Washington. Winter storm warnings are in effect for these
areas, except winter weather advisories in Wallowa County, the
Grande Ronde Valley, and in central Oregon where snow amounts will
be less due to increasing snow levels and/or unfavorable conditions
for winter storm snow amounts. In fact, snow levels will rise each
day during the next 3 days and in central Oregon the snow will
probably change to rain. However, there will likely be enough snow
to start to warrant an advisory today and Saturday. The warnings
will be in all of the Blue Mountains and all of the Cascade east
slope zones where winter storm snow amounts are expected. In
addition to the snow, winds will increase which will cause
considerable blowing and drifting of snow in the higher elevations
where temperatures will be colder and snow will be drier and more
powdery. In the lower elevations, there may be a mixture of snow
this morning before the snow changes to rain by late morning or
afternoon. There could be light accumulations in the higher terrain
of the lower elevations such as the Blue Mountain Foothills and the
Horse Heaven Hills. However, snow levels will rise and change all
the snow to mainly rain. The time length of the winter weather
highlights covers several days due to the training effect of one
Pacific system after another moving into the region. Winds will be
increasing and will peak late Saturday into Saturday night. These
weather systems will be coming in before a significant arctic air
mass moves into the region during the extended period where some
snow will be expected at all elevations. 88
LONG TERM...Sunday night through Friday...Very active pattern
for next week with the coldest air of the season infiltrating the
region. Long wave troughing with cold upper low over southwest
Canada is reinforced as a series of potent upper lows/troughs rotate
through the flow aloft and into the PacNW. The first system will be
departing Sunday night. Rain showers in the basin will transition to
snow behind the cold front, but should end by Monday morning. Snow
continues in the moist west-northwest flow aloft. Much colder air
filters into the region on Monday with highs in the upper 20s to
30s. Breezy winds also expected through Monday with the frontal
passage. The next system will quickly work into the region Monday
night into Tuesday. It will have a little more of a southerly
trajectory with the surface low working across southern Oregon. With
colder air in place, expect a good chance for accumulating snow
across the region, especially on backside of low from central OR up
through southeast WA. This system is quite progressive and will exit
the region Tuesday night with snow showers ending across much of the
region as the parent Canadian low kicks east and the region falls
under brief ridging pattern. The lower track of the Tuesday system
will bring the coldest temperatures seen this season in its wake.
Highs Tuesday and Wednesday will be in the teens and 20s with lows
in the single digits and teens. Models differ a bit from midweek on,
but the general trend is for a strong low to drop south from Gulf of
Alaska towards PacNW Wednesday. This system will likely stall out
off the coast, but warm front expected to lift across the region Wed
night into Thursday SW flow into the region, with snow showers
expected across the region through the end of the work week as
series of troughs rotate around the low in the warmer and more moist
flow aloft. Even with the warmer temps, expect snow showers even in
the basin. Highs Thursday and Friday should be in the 20s and 30s.
Breezy ridgetops winds also possible with increasing southerly flow
aloft. Some stronger winds could mix down to the surface, especially
in favored downsloping locations in central OR, along the foothills
of the Blues/Wallowas and through Grande Ronde valley.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 42 34 47 34 / 60 70 60 30
ALW 42 38 52 38 / 70 90 80 50
PSC 41 34 48 37 / 60 50 40 10
YKM 37 27 47 28 / 60 40 30 20
HRI 43 35 52 35 / 60 60 40 20
ELN 34 27 39 27 / 80 50 40 20
RDM 42 32 41 28 / 50 60 60 40
LGD 30 30 44 29 / 60 100 90 60
GCD 35 33 39 33 / 40 80 80 60
DLS 41 37 49 35 / 80 70 60 50
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 10 AM PST Monday for ORZ502-503-509.
Winter Weather Advisory until 4 PM PST Saturday for ORZ049-050-
511.
WA...Winter Storm Warning until 10 AM PST Monday for WAZ030.
Winter Storm Warning until 10 AM PST Monday for WAZ520.
&&
94/82/82The national radar mosaic for the moment the first event began.
5 heavy snow. Local standard time, as filed.
Ten inches of snow in Sunriver.
Eight inches of snow 1 south of Long Creek and 11 NNE Spray.
Eleven inches snow at High Ridge Snotel, 12 inches 9 N Elgin.
Six inches of snow 1 SE Flora 7.5 inches 1 WNW Joseph.
New snow of 11.5 inches in Summerville. Widespread snow accumulations of 5-6 inches throughout the valley.
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, January 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: 869464, 869467, 869469, 869444, 869458.