Heavy Snow in Idaho, February 15 to 17, 2021

Name: Heavy Snow in Idaho, February 15 to 17, 2021
Start: 2021-02-15T12:00
End: 2021-02-17T01:00
Location: Idaho

February 15 to 17, 2021 · NWS MSO · 2 events in 2 counties and zones

Abundant sub-tropical moisture was lifted over cold low-level air leading to widespread snow.

Where it happened

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.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 2

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.

What happened

The episode as NWS MSO wrote it up.

Abundant sub-tropical moisture was lifted over cold low-level air leading to widespread snow.

What forecasters said that day

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 15, 7:25 AM PST, 4 hours 35 minutes earlier.

Area forecast discussion, Feb 15, 7:25 AM PST, 4 hours 35 minutes before

Area Forecast Discussion...UPDATED
National Weather Service Missoula MT
825 AM MST Mon Feb 15 2021

.UPDATE...Have added all of northwest Montana and the
Butte/Blackfoot region of southwest Montana into Winter Weather
Advisories through later this evening for continuous light to
moderate snow and related travel impacts.

&&

.AVIATION...A prolonged snow event has begun at KSMN. Snow will
spread towards all terminals this morning, eventually reaching
KBTM by about 15/1300Z. Expect snow to continue through Wednesday,
dropping visibility and ceilings at all terminals. Snow will also
obscure terrain across the entire Northern Rockies airspace and
will be most pronounced over the Clearwater and Bitterroot Ranges.

&&

.PREV DISCUSSION... /ISSUED 733 AM MST Mon Feb 15 2021/

UPDATE...Upgraded the Winter Weather Advisory over the
Grangeville to Orofino area of Idaho to a Winter Storm Warning
through Tuesday morning (11 am PST). Extended ongoing Winter
Weather Advisories.

Snow throughout north central Idaho will continue through the day
with little warming to change snow over to a wintry mix, thus
increasing snow amounts and longevity of snow related impacts. A
Winter Storm Warning has been issued in place of a Winter Weather
Advisory for the Camas Prairie region including Grangeville
through Orofino.

Other Winter Weather Advisories in the region have also been
extended, with snow amounts increased in the forecast
(particularly for the Missoula/Bitterroot valleys).

PREV DISCUSSION... /ISSUED 242 AM MST Mon Feb 15 2021/

DISCUSSION...Early morning satellite imagery and radar returns
show precipitation increasing over eastern Washington and Oregon
as moist, northwest flow sets up over the Pacific Northwest and
into the Northern Rockies. Some of this moisture has already made
its way into north-central Idaho this morning. The remainder of
the Northern Rockies will see snow in varying degrees by this
afternoon. Snow will favor Clearwater and Idaho Counties and parts
of west-central Montana today, especially the mountains of the
Clearwater and Bitterroot Ranges. The Missions and Rattlesnake
will also be seeing some modest accumulations. As temperatures
moderate in Idaho with the incoming warmer air, snow levels may
rise above the Camas Prairie, but there is some question on how
much warming will be realized at lower elevations. For instance,
the moisture profile over Orofino points to the potential for snow
intensities that could force the snow level to remain at the
valley floor and maybe only briefly change to a rain/snow mix this
afternoon. If snow levels remain low, the forecast snow amounts
may be underdone in the valleys of north-central Idaho. Moist
westerly flow continues through Wednesday. This setup will bring a
hefty boost of 1 to 2 feet of snow to the snowpack of the
Clearwaters, with lower confidence of 3 feet, by Wednesday
morning. The Bitterroots and Missions will also fare quite well.
Winter Weather Advisories are in effect through Tuesday or
Wednesday as travel will be impacted over the next couple of days.

By Wednesday night, a short-lived ridge builds over the Northern
Rockies,resulting in a break from winter weather until Thursday
evening. This is when a closed system of low pressure off the
coast of British Columbia will send another round of Pacific
moisture into the Northern Rockies. This event will bring
continued snow to the region into the weekend and potentially
beyond.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory until 5 PM MST this afternoon
     Butte/Blackfoot Region.

     Winter Weather Advisory until noon MST Tuesday
     Bitterroot/Sapphire Mountains.

     Winter Weather Advisory until noon MST Tuesday
     Missoula/Bitterroot Valleys.

     Winter Weather Advisory until 11 PM MST Tuesday Lower Clark Fork
     Region.

     Winter Weather Advisory until 5 PM MST this afternoon
     Flathead/Mission Valleys...Kootenai/Cabinet Region...West
     Glacier Region.

     Winter Weather Advisory until 8 AM MST Wednesday Potomac/Seeley
     Lake Region.

ID...Winter Weather Advisory until noon MST Tuesday Eastern Lemhi
     County...Western Lemhi County.

     Winter Weather Advisory until 11 AM PST Wednesday Northern
     Clearwater Mountains...Southern Clearwater Mountains.

     Winter Storm Warning until 11 AM PST Tuesday Orofino/Grangeville
     Region.

     Winter Weather Advisory until 11 AM PST Tuesday Lower Hells
     Canyon/Salmon River Region.

&&

In the hours before

Local storm report, Feb 15, 8:04 AM PST, 3 hours 56 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
904 AM MST MON FEB 15 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0903 AM     SNOW             8 N FINLEY POINT        47.85N 114.04W
02/15/2021  M4.0 INCH        LAKE               MT   TRAINED SPOTTER

            4 INCHES OF SNOW SINCE 12 PM 2/14.

&&

AL

Local storm report, Feb 15, 8:05 AM PST, 3 hours 55 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
905 AM MST MON FEB 15 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0700 AM     SNOW             EVERGREEN               48.22N 114.27W
02/15/2021  M2.0 INCH        FLATHEAD           MT   COCORAHS

            COCORAHS STATION MT-FH-29 EVERGREEN.

&&

AL

Local storm report, Feb 15, 9:40 AM PST, 2 hours 20 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1040 AM MST MON FEB 15 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0920 AM     SNOW             4 NW NOXON              48.03N 115.85W
02/15/2021  M2.1 INCH        SANDERS            MT   COCORAHS

            COCORAHS STATION MT-SN-2 4 WNW NOXON.

&&

AL

Local storm report, Feb 15, 9:41 AM PST, 2 hours 19 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1041 AM MST MON FEB 15 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 AM     SNOW             1 WSW AHSAHKA           46.50N 116.34W
02/15/2021  M3.0 INCH        CLEARWATER         ID   COCORAHS

            COCORAHS STATION ID-CW-6 AHSAHKA.

&&

AL

Local storm report, Feb 15, 10:40 AM PST, 1 hour 20 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1140 AM MST MON FEB 15 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0930 AM     SNOW             CARDIFF                 46.57N 115.81W
02/15/2021  M6.0 INCH        CLEARWATER         ID   PUBLIC

&&

AL

Local storm report, Feb 15, 10:41 AM PST, 1 hour 19 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1141 AM MST MON FEB 15 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0900 AM     SNOW             OROFINO                 46.48N 116.26W
02/15/2021  M2.8 INCH        CLEARWATER         ID   PUBLIC

&&

AL

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

2 heavy snow. Local standard time, as filed.

Heavy Snow, Orofino / Grangeville Region

When: February 15, 12:00 PM PST to February 17, 1:00 AM PST
Where: Orofino / Grangeville Region forecast zone
Reported by: Social Media
Coordinates: 46.259, -115.562 (the zone’s center; the record gives no point)

Widespread hazardous driving conditions occurred due to heavy snow, even at the lowest elevations such as Orofino. Snowfall of 11-15 inches was typical resulting in school and public services closure. Lesser snow amounts were noted on the Camas Prairie with around 6 inches of accumulation.

Heavy Snow, Southern Clearwater Mountains

When: February 15, 5:00 PM PST to February 17, 1:00 AM PST
Where: Southern Clearwater Mountains forecast zone
Reported by: Department of Highways
Coordinates: 45.844, -115.467 (the zone’s center; the record gives no point)

A combination of heavy snow and falling trees (around 30-40 trees) caused power outages and blocked roads throughout the zone. The area from Lowell to just west of Bald Mountain on US Highway 12 received 18 inches of heavy snow, which was very significant for these lower elevations. Also, driving was very difficult on Mt. Idaho grade and in the Dixie area where they received 17.8 inches from the storm.

What these are

Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Idaho in 2021 Every state in 2021 This day in weather history Warnings in Idaho, February 2021

Sources

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: 937908, 937910.