An upper level trough moved into the Pacific Northwest enhancing ongoing shower activity and lowering snow levels. This allowed for heavy snow to fall across portions of the Oregon Cascades.
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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 PQR wrote it up.
An upper level trough moved into the Pacific Northwest enhancing ongoing shower activity and lowering snow levels. This allowed for heavy snow to fall across portions of the Oregon Cascades.
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 Portland, OR wrote its last area forecast discussion before the first event at Mar 12, 2:58 PM PST, 4 hours 2 minutes earlier.
Area Forecast Discussion
National Weather Service Portland OR
358 PM PDT Wed Mar 12 2025
.SYNOPSIS...A series of weather systems will continue lowland
rain, Cascade snow, and breezy winds through early next week.
Tomorrow (Thursday), thunderstorms are possible across the area
which could lead to heavy rain, lightning, and small hail at
times. If traveling through the Cascades over the next 4-5
days, prepare for hazardous winter weather conditions.
&&
.SHORT TERM...Now through Saturday...Radar imagery and surface
observations as of early Wednesday afternoon depicts shower
activity across northwest Oregon and southwest Washington as a
cold front approaches the region. Expect increasing rain and
Cascade snow tonight as the associated upper level trough moves
into the Pacific Northwest and drops snow levels to 1500-2500
feet. Winter Weather Advisories remain in effect for the south
WA and north OR Cascades through late Thursday evening, however,
increased snow amounts for the Cascades between Marion and Lane
Counties have warranted an upgrade to a Winter Storm Warning
for these zones. Those traveling through the Cascades should
expect hazardous winter weather conditions and refer to
ODOT/WSDOT for any travel restrictions.
Tomorrow (Thursday), expect post-frontal showers with a 20-30%
chance for thunderstorms across the entire region. The upper
level trough will usher in colder temperatures aloft (850 mb
temps around -4 to -5 deg C), steepening lapse rates and
supporting an unstable atmosphere. This is validated by HREF
guidance, which shows MUCAPE values between 100-200 J/kg (good
enough here for thunderstorms). Model soundings are also showing
this instability hitting the hail growth zone. Any passing
thunderstorms may bring brief heavy rain, lightning, gusty
outflow winds, and/or small hail. Expect this thunderstorm
threat to diminish after sunset tomorrow. Remember when thunder
roars, go indoors!
Friday to Saturday, the next weather system approaches the
Pacific Northwest, bringing another round of rain and Cascade
snow. As the warm front lifts over the area Friday morning, snow
levels will rise to 2500-3500 feet. Winds at 850 mb turn more
west southwesterly, which will support orographic enhancement of
precipitation. Heavy snow is likely over the Cascades with this
system, so a Winter Storm Watch has been issued from early
Friday morning to late Saturday afternoon. Forecast snow totals
across the Cascades during this timeframe is 1 to 2 feet, so
expect hazardous travel conditions through the passes. If you
have to travel through the passes this weekend, winterize your
vehicle and have a winter emergency driving kit readily
available. -Alviz
&&
.LONG TERM...Saturday night to Tuesday...The aforementioned
Friday to Saturday system is almost immediately followed by
secondary and deeper upper-level trough Sunday/Monday. There is
added complexity of a warm-frontal boundary initially pushing
into western Oregon Saturday night and Sunday morning which
would briefly push snow-levels up to 4500-5000 feet before
falling again by Sunday night. However, along the Cascades
crests this secondary system could easily dump another foot of
snow or more. The latest NBM probabilities for 12 inches or more
of snow accumulation have increased to 80-90% for Santiam and
Willamette Passes, while remaining around 40-50% for highway 26
near Government Camp. All in all, winter certainly isn’t done
with the Pacific Northwest and if you plan on traveling over the
Cascades through the weekend prepare for winter weather conditions
and take the necessary precautions to ensure a safe trip (same
advice given in the short term discussion).
Moving back to the interior lowlands, still not expecting too
much in the way of impacts with these series of storms Friday
through Sunday/Monday other than breezy conditions and
additional rainfall. While local rivers may see some slight
rises, the 10-day HEFS (Hydrologic Ensemble Forecast System)
probabilities for rivers to reach minor flood stage are
generally less than 10-15%. In terms of winds, there is still
some uncertainty but it generally isn't looking impactful for
now. Wind speeds Saturday night to Sunday will ultimately depend
on the exact strength and track of the low pressure system. If
the low tracks further offshore (most likely scenario), it would
just lead to breezy southerly winds with gusts of 25-35 mph for
the Willamette Valley and gusts of 40-50 mph for the coast. If
the low tracks close to or right along the coastline, it would
induce stronger winds with maximum gusts potentially exceeding
55 mph. In this case, winds this strong could potentially lead
to isolated power outages and/or downed trees. Currently, there
is a 20-40% chance for wind gusts exceeding 55 mph along the
coast and a 30-40% chance for wind gusts exceeding 40 mph inland
with this system.
At least there is good agreement between both deterministic and
ensemble guidance in a return to slightly calmer conditions
around Tuesday of next week due to a transient ridge of high
pressure shifting into the Pacific Northwest. -Alviz/Schuldt
&&
.AVIATION...Showery postfrontal conditions are producing a
mixture of MVFR/VFR cigs throughout the area. Mixed MVFR/VFR
cigs continue, trending back fully to MVFR (70-80% confidence)
around 06z Thu as a secondary front pushes through, creating
slightly stronger rain. MVFR cigs then continue until around
10-12z Thu, when rain weakens drastically, and we trend towards
VFR for all terminals. Southerly winds with gusts under 15 kts,
turning southwest by 0z Thu. Gusts up to 10-15 kt remain
possible through the rest of the period.
PDX AND APPROACHES...Mixed VFR/MVFR cigs which will be somewhat
bouncy before 4-6z. Rain increases slightly around 4-6z Thu as
another front pushes in, bringing 70-80% chance of solidly MVFR
cigs while rain is ongoing. Front moves out of the area around
10-12z Thu, and trending towards VFR afterwards with 80%
confidence. Southerly winds turn southwesterly around 4z Thu,
with gusts under 15 kts throughout the entire period. /JLiu
&&
.MARINE...Seas remain slightly higher than model guidance, with
current conditions around 10-12 ft at 12 to 14 seconds. Winds
have fallen off considerably, currently under 10 kts. That
said, the Small Craft Advisory remains in place until Thursday
evening due to wave heights above 10 ft. Thursday afternoon also
sees the potential for some occasional thunderstorms throughout
the area. The next system begins moving in late Thursday night
into Friday morning, with some marginal Gales or high end Small
Craft winds from the south, right around 35 kt. Still waiting on
further high res model guidance before making a decision on
this. For the rest of Friday, a period of Hazardous Seas looks
possible as winds drop but waves come up ahead of the next
front. Seas potentially up to 14-18 ft possible by Friday
evening, increasing even further on Saturday to potentially
15-20 ft.
Strong uncertainty regarding the front coming in Saturday
evening, but looking at the potential for much stronger winds
from the south. High end scenarios (currently around 20% chance)
show potentially low-end Storm force winds peaking Saturday
night. That said, currently the most likely scenario is high-end
Gales around 45 kts. We will continue to evaluate potential for
hazardous conditions. /JLiu
&&
.BEACH HAZARDS...High threat of sneaker waves through Thursday
night as a strong westerly swell of 9-11 ft at 14-15 seconds is
expected until then. Waves weaken in the latter half of Thursday
night, and threat of sneaker waves should end at that time.
Waves can run up significantly farther on a beach than normal,
including over rocks and jetties. Sneaker waves can suddenly
knock people off of their feet and quickly pull them into the
frigid ocean, which may lead to serious injury or drowning.
Beach goers beware, including razor clammers. Never turn your
back to the ocean. /JLiu
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 11 PM PDT Thursday for ORZ126.
Winter Storm Watch from late Thursday night through Saturday
afternoon for ORZ126>128.
Winter Storm Warning until 11 PM PDT Thursday for ORZ127-128.
WA...Winter Weather Advisory until 11 PM PDT Thursday for WAZ211.
Winter Storm Watch from late Thursday night through Saturday
afternoon for WAZ211.
PZ...Small Craft Advisory until 5 PM PDT Thursday for PZZ210.
Small Craft Advisory until midnight PDT Thursday night for
PZZ251>253-271>273.
&&
www.weather.gov/portland
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x.com/NWSPortlandThe national radar mosaic for the moment the first event began.
2 heavy snow. Local standard time, as filed.
The Salt Creek Falls SNOTEL at 4220 ft recorded 12 inches of snow between 2000 03/12 and 1900 03/13. Additionally the Roaring River SNOTEL at 4960 ft recorded 12 inches of snow between 1900 03/12 and 0800 3/13.
The Bear Grass SNOTEL at 4720 ft recorded 16 inches of snow between 2100 3/12 and 1700 3/13 with 12 inches hit 0600 3/13.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2025Every state in 2025This day in weather historyWarnings in Oregon, March 2025
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: 1240174, 1240176.