A deep arctic air mass combined with overrunning moisture made for a high impact event for parts of north-central Idaho with heavy snow leading to slick roads and school closures.
Every event with a place to put it; 2 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 MSO wrote it up.
A deep arctic air mass combined with overrunning moisture made for a high impact event for parts of north-central Idaho with heavy snow leading to slick roads and school closures.
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 Missoula, MT wrote its last area forecast discussion before the first event at Feb 3, 3:03 AM PST, 5 hours 57 minutes earlier.
Area Forecast Discussion
National Weather Service Missoula MT
403 AM MST Sun Feb 3 2019
...SIGNIFICANT WINTER STORM UNDERWAY...
.DISCUSSION...The arctic air has made it into the Flathead Valley
as of 3 am this morning with winds gusting to 50 mph combined with
snow and blowing snow. Last evening rain fell in many locations
and when combined with temperatures in the single digits and
teens, strong winds and falling snow makes for difficult travel
conditions. Be very careful if you have to drive as there could be
an ice layer under the snow causing it to be slicker than one
would think! As the arctic cold front continues to push west and
south, expect areas of freezing rain, especially along the Highway
200, I-90 and US-93 corridors. Eventually the arctic air will
become deep enough causing a switch-over to all snow.
The radar has filled in over the Mission and Flathead Valleys this
morning as expected as the colder air continues to shift
southward, undercutting the moist flow aloft.
The arctic boundary will eventually stall by this afternoon from
Clearwater County, Idaho east and south towards Hamilton/Darby and
east and south towards Divide which is south of Butte. Waves of
moisture moving over this feature will cause:
1) Periods of heavy snow along the I-90 corridor, central
Bitterroot Valley and portions of Highway 200 corridor especially
towards Helmville. Also near Headquarters and Pierce, Idaho.
2) Freezing rain near or south of Hamilton, MT towards Darby and
connecting valleys towards Painted Rocks. It is also possible over
portions of central or western Clearwater County.
The cold air will push south towards the Camas Prairie, ID and
Grangeville area tonight which will cause a changeover to snow.
Snow intensities could become quite heavy at times into Monday
morning. Confidence is low, but even the Riggins area could
changeover to a period of decent snow Monday morning.
On Monday, the arctic boundary will be draped over central Idaho
extending east into southwest Montana. Weak disturbances will
provide enough lift and moisture to keep snow going in many
locations. Other places like over Lincoln County could see decent
breaks in the snow. Some locations could continue to deal with
freezing rain near the stationary front..one area of concern is
the southern Bitteroot Valley where the arctic air will be
shallow enough to support that. There could be enough solar
penetration to allow for ground temperatures to warm above
freezing.
Areas of light snow will continue Tuesday and Wednesday as we
remain under an upper level trough with frigid arctic air in
place. One focused area of heavier snowfall and gusty winds is
expected across Lemhi County into southwest Montana Tuesday into
early Wednesday with travel impacts likely. Meanwhile, highs will
be in the teens and 20s, with overnight lows from below zero to
single digits in western Montana with teens and 20s in north-
central Idaho. Breezy easterly winds will continue to keep wind
chills at uncomfortable to dangerous levels.
General agreement continues that most of Thursday will be dry but
continued cold. Then a wintry period may once again become
established Friday into next weekend. Current forecast model
projections show several bouts of snowfall with a renewed push of
Arctic air.
&&
.AVIATION...A winter storm is underway across the Northern
Rockies. Expect strong north to east winds to 45 knots near
canyons and also on ridgetops. Periods of moderate to heavy
snow, blowing snow, and reduced visibility are expected
across west-central Montana including MSO and possibly BTM during
the day today. Freezing rain is anticipated over portions of
Clearwater County and southwest Montana as the arctic cold front
stalls in those areas by 03/2100Z. The Grangeville area in Idaho
will experience a cold front passage by 04/0300Z causing a
changeover to moderate to heavy snow that will last through
04/1600Z.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Warning until 2 PM MST Monday Butte/Blackfoot
Region.
Winter Storm Warning until 2 PM MST Monday Bitterroot/Sapphire
Mountains.
Winter Storm Warning until 2 PM MST Monday Missoula/Bitterroot
Valleys.
Winter Storm Warning until 2 PM MST Monday Lower Clark Fork
Region.
Winter Storm Warning until 2 PM MST Monday Flathead/Mission
Valleys.
Winter Storm Warning until 2 PM MST Monday West Glacier Region.
Winter Storm Warning until 2 PM MST Monday Kootenai/Cabinet
Region.
Winter Storm Warning until 2 PM MST Monday Potomac/Seeley Lake
Region.
ID...Winter Weather Advisory from 8 AM this morning to 2 PM MST
Monday Eastern Lemhi County...Western Lemhi County.
Winter Storm Warning from 4 PM this afternoon to 4 PM PST Monday
Lower Hells Canyon/Salmon River Region.
Winter Storm Warning from 4 PM this afternoon to 4 PM PST Monday
Orofino/Grangeville Region.
Winter Storm Warning until 1 PM PST Monday Southern Clearwater
Mountains.
Winter Storm Warning until 1 PM PST Monday Northern Clearwater
Mountains.
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</html>PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
810 AM MST SUN FEB 3 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0623 AM NON-TSTM WND GST HELMVILLE 46.87N 112.96W
02/03/2019 M63 MPH POWELL MT MESONET
63 MPH WIND GUST, WITH HEAVY SNOW. BLOWING
AND DRIFTING SNOW OCCURRING.
&&The national radar mosaic for the moment the first event began.
2 heavy snow. Local standard time, as filed.
Snowfall of 4 to 8 inches was common, while up to 12 inches was reported at Cardiff Spur. This snowfall led to difficult travel at times along with school closures.
Snowfall of 4 to 8 inches was typical including 6 inches in Orofino and Grangeville. This snowfall led to difficult travel at times along with school delays and closures.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2019Every state in 2019This day in weather historyWarnings in Idaho, February 2019
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 2026-09-30. Each event’s entry at NCEI: 801230, 801232.