Winter Storm in Montana, April 14, 2015

Name: Winter Storm in Montana, April 14, 2015
Start: 2015-04-14T12:30
End: 2015-04-14T17:00
Location: Montana

April 14, 2015 · NWS MSO · 1 event in 1 county or zone

Where it happened

Every event with a place to put it; 1 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: 1

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.

A slow-moving and very cold Pacific trough, originating from eastern Siberia, moved into central Idaho and western Montana bringing with it snow and wind. Because the upper level jet orientation was southerly, many places saw an extended period of snow behind the cold front passage. Central Idaho saw the effects of this system first in the morning as moderate to heavy snow fell caused slushy roads. Then as the cold front marched eastward, conditions deteriorated across southwest Montana. This was a big change from the day before in which temperatures were in the 60s and low 70s.

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 Apr 14, 12:15 PM MST, 15 minutes earlier.

Area forecast discussion, Apr 14, 12:15 PM MST, 15 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
115 PM MDT TUE APR 14 2015

.UPDATE...HAVE ALLOWED THE WINTER WEATHER ADVISORY FOR WHITEBIRD
HILL AND THE GRANGEVILLE/CAMAS PRAIRIE AREA TO EXPIRE AT NOON.
HAVE ISSUED NEW WINTER WEATHER ADVISORIES FOR EASTERN LEMHI COUNTY
AND THE BUTTE/BLACKFOOT REGION.

&&

.DISCUSSION...A STRONG, SLOW MOVING COLD FRONT CONTINUES TO MARCH
ACROSS THE NORTHERN ROCKIES THIS AFTERNOON. LIGHTER PRECIPITATION
RATES COMBINED WITH SOLAR RADIATION HAVE LEAD TO SIGNIFICANT
IMPROVEMENT OVER WHITEBIRD HILL AND THE GRANGEVILLE/CAMAS PRAIRIE
AREA OF WEST CENTRAL IDAHO AND THUS THE ADVISORY HAS BEEN ALLOWED
TO EXPIRE. MEANWHILE HAVE ISSUED A NEW SET OF ADVISORIES FOR
SOUTHWEST MONTANA AND EASTERN LEMHI COUNTY WHILE ALSO EXTENDING
THE ADVISORY FOR THE BITTERROOT/SAPPHIRE MOUNTAINS (INCLUDING LOLO
AND LOST TRAIL PASS). THESE AREAS ARE ALL BEING HIGHLIGHTED BY THE
LATEST MODEL DATA AS HAVING EXCELLENT FORCING FOR HEAVIER
PRECIPITATION RATES AND A GOOD CHANCE FOR ACCUMULATING SNOWFALL
WHICH MAY AFFECT THE EVENING RUSH HOUR HOME. THESE ADVISORIES WILL
CONTINUE THROUGH WEDNESDAY MORNING.

&&

.AVIATION...THE COLD PACIFIC TROUGH WILL CONTINUE TO TRACK ACROSS
THE NORTHERN ROCKIES TONIGHT THROUGH WEDNESDAY MORNING. EXPECT
NUMEROUS SNOW SHOWERS(WITH CEILING AND VISIBILITY REDUCTIONS) AND
GUSTY NORTHERLY WINDS FROM LEMHI COUNTY TO SOUTHWEST MONTANA
INCLUDING KBTM AND ALONG THE CONTINENTAL DIVIDE DURING THIS
PERIOD. THERE IS GOOD CHANCE FOR A PERIOD OF HEAVY SNOW WITH
VISIBILITY LESS THAN ONE HALF MILE ACROSS SILVER BOW & DEER LODGE
COUNTIES INCLUDING KBTM BETWEEN 14/1900Z AND 14/2300Z BUT
CONFIDENCE LOWER ON EXACTLY WHEN AND WHERE THIS WILL OCCUR. AN
UPPER LEVEL RIDGE WILL BEGIN TO BUILD IN FROM THE NORTHWEST
BRINGING DRIER AND MORE STABLE CONDITIONS WITH IT DURING THE DAY
ON WEDNESDAY AND THURSDAY. PATCHY FOG IS POSSIBLE IN THE FLATHEAD
VALLEY WEDNESDAY MORNING. NOBLE

&&

.PREV DISCUSSION... /ISSUED 408 AM MDT TUE APR 14 2015/

..COLDER TODAY WITH BREEZY CONDITIONS AND SNOW, ESPECIALLY OVER
MOUNTAIN PASSES...

..HARD FREEZE POSSIBLE WEDNESDAY AND THURSDAY MORNINGS WITH
POSSIBLE IMPACTS TO SENSITIVE VEGETATION...

DISCUSSION...A SLOW MOVING COLD FRONT CURRENTLY LOCATED IN
EASTERN WASHINGTON AND OREGON WILL MOVE THROUGH CENTRAL IDAHO
EARLY THIS MORNING AND WESTERN MONTANA MID MORNING INTO THE
AFTERNOON. WIDESPREAD PRECIPITATION IS EXPECTED TO DEVELOP, WITH
THE HEAVIEST PRECIPITATION EXPECTED IN CENTRAL IDAHO AND ALONG THE
IDAHO/MONTANA BORDER. SNOW LEVELS ARE EXPECTED TO QUICKLY LOWER
BEHIND THE COLD FRONT TO AROUND 3000 FEET, BRINGING SNOW OR A
RAIN/SNOW MIX TO MANY VALLEYS AND ACCUMULATING SNOW ON MOUNTAIN
PASSES. THE BIGGEST IMPACT FROM SNOW IS EXPECTED IN NORTH CENTRAL
IDAHO AND OVER THE MOUNTAIN PASSES ALONG THE IDAHO/MONTANA
(LOOKOUT, LOLO AND LOST TRAIL) BORDER DUE TO THE HEAVIER NATURE
OF PRECIPITATION AND TIMING OF THE COLD FRONT DURING THE MORNING
HOURS. WINTER WEATHER ADVISORIES REMAIN IN PLACE THROUGH THIS
AFTERNOON. AS PRECIPITATION BECOMES MORE SHOWERY THIS AFTERNOON,
IT IS POSSIBLE SOME OF THE MOUNTAIN PASSES IN SOUTHWEST MONTANA
AND ALONG THE CONTINENTAL DIVIDE (MACDONALD, HOMESTAKE, MARIAS)
COULD SEE A QUICK COVER OF SNOW, POSSIBLY BRIEFLY SLOWING TRAVEL.

ANOTHER IMPACT WITH TODAY'S FRONT WILL BE FOR THE DEVELOPMENT OF
GUSTY WEST TO NORTHWEST WINDS. THE STRONGEST WINDS ARE EXPECTED
ACROSS SOUTHWEST MONTANA INTO LEMHI COUNTY WHERE SOME GUSTS TO
NEAR 40 MPH ARE POSSIBLE. BREEZY CONDITIONS ON FLATHEAD LAKE WILL
CAUSE CHOPPY CONDITIONS FOR BOATERS THROUGH THIS AFTERNOON.

SNOW SHOWERS WILL LINGER INTO THE EVENING, BUT SHOULD GRADUALLY
DECREASE OVER NIGHT INTO WEDNESDAY. ALTHOUGH CLOUDS AND SOME
LIGHT WIND IS EXPECTED TO LINGER INTO WEDNESDAY MORNING, A MUCH
COLDER AIRMASS BEHIND TODAY'S COLD FRONT WILL ALLOW FOR WIDESPREAD
TEMPERATURES INTO THE 20S.

WEDNESDAY NIGHT/THURSDAY MORNING...
AS THE WEATHER SYSTEM MOVES OFF TO OUR EAST, CLEAR SKIES WILL LEAD
TO THE COLDEST TEMPERATURES OF THE WEEK. MANY VALLEYS WILL SEE
TEMPERATURES IN THE LOW 20S AND POSSIBLY TEENS FOR HIGHER
ELEVATION VALLEYS OF IDAHO AND MONTANA. THE COLD TEMPERATURES
COULD DAMAGE SENSITIVE PLANTS.

THURSDAY AND FRIDAY...
A BUILDING RIDGE OF HIGH PRESSURE WILL BRING WARM AND DRY WEATHER
TO THE REGION. HIGH TEMPERATURES ON FRIDAY WILL BE IN THE MID 60S
TO LOW 70S FOR MOST AREAS ACROSS THE REGION.

SATURDAY AND SUNDAY...
A QUICK WEATHER DISTURBANCE WILL BRING MOUNTAIN SNOW AND RAIN/SNOW
MIX TO THE VALLEYS ON SATURDAY. THE BEST AREA FOR PRECIPITATION
LOOKS TO BE ALONG THE CONTINENTAL DIVIDE. WESTERN MONTANA SHOULD
EXPECT A SHOWERY AND COOL SATURDAY. THE SYSTEM WILL BEGIN TO EXIT
THE REGION SATURDAY NIGHT, BUT LIGHT SHOWERS COULD BE POSSIBLE ON
SUNDAY.

AVIATION...A SLOW MOVING COLD FRONT IS MAKING ITS WAY INTO
NORTH- CENTRAL IDAHO AS OF 14/1000Z AND WILL MOVE INTO WESTERN
MONTANA BY 14/1500Z. EXPECT LOWERING CEILINGS AND WIDESPREAD
MOUNTAIN OBSCURATIONS AS SNOW LEVELS LOWER TO VALLEY BOTTOMS.
THERE IS THE POTENTIAL FOR STRONG WEST TO NORTHWEST WIND GUSTS UP TO
35 KNOTS FOR KSMN AND KBTM ASSOCIATED WITH THE FRONTAL PASSAGE
BETWEEN 14/1700Z AND 14/2100Z. SNOW SHOWERS WILL PERSIST ACROSS
THE REGION THROUGH THIS EVENING, BEFORE GRADUALLY DECREASING
TOWARDS WEDNESDAY MORNING.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY UNTIL 3 PM MDT THIS AFTERNOON ABOVE 3000
     FEET FOR THE LOWER CLARK FORK REGION.

     WINTER WEATHER ADVISORY UNTIL 9 AM MDT WEDNESDAY
     BITTERROOT/SAPPHIRE MOUNTAINS.

     WINTER WEATHER ADVISORY UNTIL 9 AM MDT WEDNESDAY BUTTE/BLACKFOOT
     REGION.

ID...WINTER WEATHER ADVISORY UNTIL 2 PM PDT THIS AFTERNOON ABOVE 3000
     FEET FOR THE NORTHERN CLEARWATER MOUNTAINS...SOUTHERN
     CLEARWATER MOUNTAINS.

     WINTER WEATHER ADVISORY UNTIL 9 AM MDT WEDNESDAY EASTERN LEMHI
     COUNTY.

&&

In the hours before

Local storm report, Apr 14, 9:37 AM MST, 2 hours 53 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1037 AM MDT TUE APR 14 2015

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

0834 AM     HEAVY SNOW       6 WSW SYRINGA           46.10N 115.83W
04/14/2015  M1.1 INCH        IDAHO              ID   TRAINED SPOTTER

            REPORTED THAT IT SNOWED 1.1" BETWEEN 8 AND 9
            AM PDT.

&&

NWS MISSOULA MT
IRIS SYSTEM

The radar

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

Open the radar archive at this moment

Event by event

1 winter storm. Local standard time, as filed.

Winter Storm, Butte / Blackfoot Region

When: April 14, 12:30 PM MST to 5:00 PM MST
Where: Butte / Blackfoot Region forecast zone
Reported by: Department of Highways
Coordinates: 46.306, -113.025 (the zone’s center; the record gives no point)

Due to the nature of this system, it was a major change to road conditions and most likely caught some travelers off-guard. Three main areas saw the highest impacts with the storm: The first area was around Georgetown Lake. Snowplow crews barely could keep up with the heavy snowfall even with extra equipment they had to bring in to mitigate. The second area included the Racetrack Interchange to Warm Springs along Interstate 90. Heavy wet snow caused deep slush on the road which contributed to a three vehicle car accident in that stretch. The third area that saw impacts covered a stretch of I-90 east of Butte to Homestake Pass. Blizzard-like conditions were reported by the MDT and the sharp temperature drop from the 40s to the 20s caused road temperatures cold enough for snow to stick. Weather sensors reported wind gusts to 38 mph while snow amounts up to 6 inches were estimated in the higher terrain including Homestake Pass. Two jack-knifed vehicles caused Homestake Pass to be closed for a time around 415 pm MDT.

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.

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

The same day elsewhere

Every storm in Montana in 2015 Every state in 2015 This day in weather history Warnings in Montana, April 2015

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: 560388.