An upper trough pushed several low pressure systems across the Pacific Northwest in the middle of April. The trough allowed for a much colder than normal air mass to settle into portions of eastern Washington and Oregon, allowing snow levels to drop to the surface across a majority of these areas.
Every event with a place to put it; 4 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.
An upper trough pushed several low pressure systems across the Pacific Northwest in the middle of April. The trough allowed for a much colder than normal air mass to settle into portions of eastern Washington and Oregon, allowing snow levels to drop to the surface across a majority of these areas. This ultimately resulted in snow accumulations in the mountains and lower elevations, with significant snow accumulations being observed in some mountain zones.
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 Apr 10, 3:48 AM PST, 12 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
448 AM PDT Sun Apr 10 2022
Updated Aviation Discussion.
.SHORT TERM...Today through Tuesday night...A very active
troughing pattern with multiple waves will impact the Pacific
Northwest through the short term period with widespread
precipitation and breezy to windy conditions. Because of the cold
nature of the systems, those outside of the lowest elevations of
the Columbia Basin will likely see light snow, while the mountains
will see significant accumulations. Winter weather highlights
have been adjusted to account for the latest expected snow totals
with a combination of advisories and warnings in effect through
the period. Additionally, temperatures are forecast to be 10-20
degrees below normal through the short term.
The first wave will impact the area today with the region under
northwest flow aloft. This pattern favors mountain snow with drier
conditions for the lower elevations. Could see some afternoon
showers and possibly a rumble of thunder across the northern
portion of our forecast area from Wallowa County to the
Washington Cascades. Otherwise, widespread breezy conditions will
persist through the day.
Things get more interesting as a closed upper low will undergo
rapid intensification this afternoon through tonight as it drops
down from the BC coast. The main surface low will approach the
OR/WA coast tonight as well, and will see widespread precipitation
as it tracks inland. Deterministic and ensemble guidance are in
excellent agreement that the upper low will track directly across
our forecast area Monday ushering in cold temperatures and
widespread snow. Exact snow totals are still somewhat uncertain as
EFI Shift of Tails values indicate some ensemble members
forecasting quite extreme snow for central Oregon, the Basin, and
into the Simcoe Highlands. EFI values indicate this will be an
unusual event with regard to snow totals regardless of whether or
not the extreme totals materialize.
Regarding snow totals, Monday morning, 850 mb winds from the
southeast, and a downsloping signature along the Blue Mountain
Foothills will likely lead to some drying and less precipitation.
Central Oregon will see similar downslope drying and a rain shadow
with westerly flow aloft through much of the event. At the same
time, the Washington Cascades and Simcoe Highlands will see strong
upslope flow and potentially heavy snow. By later Monday afternoon
and evening, the surface low will progress such that flow turns
upslope for the Blue Mountain Foothills and precipitation will
intensify. Breezy to windy conditions will accompany the surface
low on Monday.
Heading into Tuesday, the first low will exit to the east with
flow aloft turning northwesterly, while another upper low is
advertised to slide down the BC coast and slowly progress towards
the coast. Active weather will continue through Tuesday night.
Plunkett/86
.LONG TERM... Wednesday through Sunday... Unsettled and cool
conditions characterize the second half of the week before
trending drier over the weekend. The ECMWF Extreme Forecast
Index (EFI) continues to highlight the abnormally low temperatures
compared to typical climatology through Sunday with values ranging
from -0.8 to -0.97 for min and max temperatures. Mountain
snowfall remains the primary impact going forward.
Wednesday morning a closed upper-level low likely sits off the
coast of western Washington with west-northwesterly flow across
much of the region. This pattern continues to facilitate ample
snow shower activity over the Cascades, especially in Oregon, with
shower chances extending into the mountains of eastern Oregon,
central Oregon, and part of the Columbia Basin. Both ensemble and
deterministic guidance have this upper-level low slowly meandering
inland and weakening Thursday into Thursday night keeping showery
weather overhead however there’s still a fair amount of
uncertainty as to its exact progression. Nevertheless expect a
general uptick in shower activity as it crosses WA/OR. It’s a
similar story Friday into Saturday with most guidance picking up
on yet another developing disturbance swinging into the region out
of western British Columbia but struggling with the amplification
of the associated trough. Exploring the WPC Cluster Analysis
reveals a majority of the GEFS ensemble members projecting a much
deeper and slightly more progressive trough Thursday into Friday
compared to the ECMWF and the Canadian. Most of the Canadian
members forgo the trough all together Friday having the Pacific
Northwest in broader zonal flow comparatively. Given this
uncertainty confidence is currently low to moderate for QPF and
PoPs late in the week. A transient ridge of high pressure is
projected by most guidance to move into the region Saturday night
into Sunday bringing drier and calmer conditions.
There is higher confidence through the extended period in below
normal temperatures as alluded to by the aforementioned EFI values.
The NBM keeps temperature spreads fairly tight through the extended
period with generally 5 to 8 degrees between the 25th and 75th
percentiles. It’s worth noting there is more uncertainty regarding
the potential spread in overnight lows which would be heavily
influenced by clearing skies and winds, something that is a little
more dependent on the placement of disturbances within the overall
pattern. Nevertheless snow levels due to the cold airmass aloft will
be abnormally low for April. At night snow could fall at elevations
as low as 500 feet, rising to 1500 to 2000ft during the daytime
hours. Fortunately given the higher sun-angle and warmer road
surfaces this time of year, winter weather impacts should be
reduced for most areas outside of the mountains. 99
&&
.AVIATION... 12z TAFS... A passing weather disturbance early this
morning has brought some precipitation to the region with MVFR
conditions expected for a few hours at ALW due to light snow
reducing vis and cigs. Back to VFR around 16z. Otherwise generally
VFR conditions continue all other sites as shower activity remains
pinned near the higher terrain. Breezy winds pick up as the day
progresses with gusts around 15-25kts most sites, decreasing this
evening. A robust weather disturbance arrives later tonight into
Monday morning with lowering cigs to MVFR accompanied by light
rain/snow for RDM, BDN, DLS, and YKM. These MVFR conditions move to
the other sites as well as conditions deteriorate but this likely
occurs just outside of the TAF period. 99
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 48 33 46 30 / 30 20 60 60
ALW 50 33 50 33 / 60 20 50 60
PSC 55 36 51 36 / 20 20 40 40
YKM 52 29 48 29 / 10 30 50 30
HRI 53 35 49 34 / 20 20 50 50
ELN 48 28 46 29 / 20 20 40 20
RDM 45 30 42 24 / 10 60 60 60
LGD 41 27 42 28 / 80 20 60 70
GCD 43 28 43 26 / 60 50 70 70
DLS 52 36 48 36 / 20 80 70 50
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning from 11 PM this evening to 11 PM PDT Monday
for ORZ506.
Winter Storm Warning from 5 PM this afternoon to 5 AM PDT
Wednesday for ORZ509.
Winter Weather Advisory from 11 PM this evening to 11 PM PDT
Monday for ORZ503.
Winter Storm Warning until 5 PM PDT Monday for ORZ502.
WA...Winter Storm Warning from 11 PM this evening to 11 PM PDT Monday
for WAZ520-521.
Winter Storm Warning until 5 PM PDT Monday for WAZ030.
&&
SHORT TERM...86
LONG TERM....99
AVIATION...99The national radar mosaic for the moment the first event began.
4 heavy snow. Local standard time, as filed.
The milk Shakes SNOTEL 9 miles southwest of Ski Bluewood, WA measured 12 inches of new snow in a 24 hour period ending at 0400 PDT. A report relayed from a media partner estimated that 14 inches of new snow was measured at 0622 PDT.
The Ft. Clear Lake SNOTEL 17 miles west northwest of Pine Grove, OR measured 89 inches of new snow in a 18 hour period ending at 0600 PDT. The Hogg Pass SNOTEL measured 10 inches of new snow in a 24 hour period ending at 0600 PDT.
In Dale, OR the Oregon Dept. of Highways measured 9 inches of new snow in a 24 hour period ending at 0104 PDT. The Oregon Dept. of Highways measured 9 inches of new snow in a 24 hour period ending at 0120 PDT 8 miles north northwest of Ukiah, OR.
The Starr Ridge SNOTEL 11 miles south southwest of John Day, OR measured 7 inches of new in a 24 hour period ending at 1500 PDT. The Ochoco Meadows SNOTEL 13 miles southwest of Mitchell, OR measured 8 inches of new snow in a 24 hour period ending at 2300 PDT.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2022Every state in 2022This day in weather historyWarnings in Oregon, April 2022
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: 1024920, 1024933, 1024922, 1024928.