A shortwave trough coupled with surface cold front swept across the forecast area on Feb. 25th, producing an initial surge in snowfall across the region with breezy to gusty winds developing behind the frontal passage.
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 shortwave trough coupled with surface cold front swept across the forecast area on Feb. 25th, producing an initial surge in snowfall across the region with breezy to gusty winds developing behind the frontal passage. Behind this system, persistent northwest flow aloft reinforced by a series of shortwaves produced additional snowfall across the forecast area through the morning of Feb. 27th.
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 25, 3:14 AM PST, 3 hours 46 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
314 AM PST Thu Feb 25 2021
Updated Aviation Discussion
.AVIATION...12z TAFs...VFR conditions expected at all sites. Main
impact today will be strong winds, with wind advisory in effect for
all sites. Frontal system will arrive this morning, with winds
gusting up to and over 35 kts for most of the day, relenting only
slightly during the evening. Slight rain chances along the foothills
of the mountains this morning, but any shower will be brief and very
light. Clouds will build this morning, bkn-ovc 5-10 kft, before
clearing through the day. Sites along the Cascades will be mostly
clear by the evening, with lingering low to mid sct-bkn clouds along
the Blues. 74
&&
.PREV DISCUSSION... /issued 204 AM PST Thu Feb 25 2021/
SHORT TERM...Today through Saturday...Active weather pattern is
in store today into Saturday as two systems drop southeast across
the region in nw flow aloft. This will result in a prolonged
period of mountain snow and also wind in the lower and upper
elevations. Numerous winter warnings are in effect for nearly all
of the mountain zones where 10-24 inches of snow can be expected.
Did lower the elevation based warning for the Washington Cascade
east slopes down to 2500 feet to capture more of Snoqualmie pass
and also mentioned some decent snow accumulations in the lower
elevations of that zone. The Grande Ronde Valley and Wallowa
county will see a bit less snow but still significant
accumulations expected. Increased the winds a bit both this
afternoon/early evening and again on Friday especially over the
western half of the forecast area. HRRR and SPC HREF are showing
some 50 KT plus gusts over the higher terrain so think solid
advisory is a good bet which is handled well by the current
wind highlights. Soundings also show very steep low-mid level
lapse rates suggesting that the stronger winds aloft will mix down
to the surface. So all in all a windy couple of days is in store.
So far however the winds have not picked up in the Grande Ronde
Valley and will be monitoring that Advisory the next few hours. By
Saturday afternoon things will be quieting down as the second
upper trough exits the area. 78
LONG TERM...Saturday night through Thursday...Models in good
agreement through the weekend, but diverge heading into the work
week next week. Strong northerly flow will give way to a building
ridge by the end of the day Sunday, beginning the onset of an
overall warming trend. Behind this ridge, the flow aloft shifts SW
as a deepening cutoff low off the California coast begins to move
onshore, providing the best chance for precip in the long term.
Global ensembles largely keep lower elevations dry with only a low
chance PoPs in the mtns, but always a chance for showers given the
moisture advection supported by this synoptic pattern.
Global guidance keeps this low just to our south as it lifts, which
would keep most of the CWA dry through the week. Mtns will see at
least a slight chance for PoPs given upslope flow, but models not
suggesting anything robust at this time. High temps will flirt with
the 60s in the Basin given the SW flow, with snow levels maxing out
at 4000 ft and higher, bottoming out at around 1500 ft under calm
winds overnight around Tuesday as the northern periphery of the low
passes to our south. Overall, however, the synoptic pattern ahead
looks to support more SW flow, a break away from the dominant NW
pattern we've seen most of February, allowing us to see a taste of
spring as we head into March. 74
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 48 36 46 30 / 30 20 50 50
ALW 48 38 46 32 / 50 50 70 50
PSC 53 38 52 30 / 20 0 20 20
YKM 50 29 50 27 / 20 20 30 20
HRI 53 37 52 32 / 10 10 30 30
ELN 43 32 42 27 / 40 40 50 30
RDM 48 28 43 26 / 10 20 50 40
LGD 36 31 36 25 / 80 90 90 70
GCD 41 31 37 27 / 40 70 90 70
DLS 48 38 48 35 / 60 60 60 50
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 4 AM PST Saturday for ORZ509.
Wind Advisory from 10 AM this morning to 9 PM PST Friday for
ORZ041-044-505-507-508-510-511.
Winter Storm Warning from 7 AM this morning to 10 AM PST
Saturday for ORZ049-050-502-503.
Wind Advisory until 1 PM PST this afternoon for ORZ049.
WA...Wind Advisory from 10 AM this morning to 9 PM PST Friday for
WAZ024-026>029-521.
Winter Storm Warning from 7 AM this morning to 10 AM PST
Saturday for WAZ030.
Winter Storm Warning until 10 PM PST Friday for WAZ520.
&&
SHORT TERM...78
LONG TERM....74
AVIATION...74The national radar mosaic for the moment the first event began.
5 heavy snow. Local standard time, as filed.
A trained spotter 4 miles NNW of Wallowa, OR reported 7 inches of snowfall in a 24 hour period ending at 1245pm PST on Feb. 27th. A Cocorahs observer 2 miles SW of Wallowa, OR reported 6.3 inches at 7am PST on Feb. 27th.
The Tipton Snotel 10 miles WSW of Mount Ruth, OR reported 14 inches of storm total snow at 906am PST on Feb. 27th. The Beaver Reservoir Snotel 14 miles SSW of La Grande, OR reported 7 inches of snowfall at 722pm PST on Feb. 26th.
The High Ridge Snotel 5 miles SW of Spout Springs, OR reported 12 inches of snow accumulation from 10pm PST on Feb. 25th to 4pm PST on Feb. 26th. A Cocorahs observer 9 miles N of Elgin, OR reported 11.9 inches of snowfall at 7am PST on Feb. 27th.
A social media report originating in Cove, OR reported 10.2 inches of snowfall at 856am PST on Feb. 27th. A trained spotter 5 miles NNE of La Grande, OR reported 8 inches of snowfall at 955am PST on Feb. 26th.
A trained spotter 9 miles NW of Seneca, OR reported 9.2 inches of snowfall in a 24 hour period ending at 7am PST on Feb. 27th. The Lake Creek R.S. Snotel 18 miles ENE of Seneca reported 6 inches of snowfall at 733pm PST on Feb. 26th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2021Every state in 2021This day in weather historyWarnings in Oregon, February 2021
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: 938518, 938521, 938526, 938527, 938522.