An arctic front backed in from the northeast and moved westward across the Billings Forecast Area. A deep upslope flow was ushered in behind the front.
Every event with a place to put it; 10 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 BYZ wrote it up.
An arctic front backed in from the northeast and moved westward across the Billings Forecast Area. A deep upslope flow was ushered in behind the front. This upslope flow combined with a strong, unstable disturbance aloft, resulted in heavy snow across the central and western portions of the area, as well as the mountain foothills locations.
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 Billings, MT wrote its last area forecast discussion before the first event at Dec 14, 3:16 AM MST, 44 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
316 AM MST MON DEC 14 2015
.SHORT TERM...VALID FOR TDY AND TUE...
LITTLE IN THE WAY OF CHANGES TO THE SHORT TERM FORECAST AGAIN
THIS MORNING. SNOW STORM CROSSING THE REGION DOMINATES THE
PATTERN THROUGH THE FORECAST PERIOD...WITH STORM EXIT TO THE EAST
COINCIDING WITH END OF THE PERIOD. FOR THE MOST PART THE STORY
REMAINS THE SAME...WITH HIGH QPF PROGGED INTO THE
REGION...REASONABLE...THOUGH NOT GREAT INSTABILITY...AND DECENT
VERTICAL MOTION THROUGH DENDRITIC GROWTH ZONE...AS WELL AS MORE
FAVORABLE TEMP PROFILE THAN WITH PREVIOUS SYSTEMS. BEST SNOW
AMOUNTS SHOULD STILL BE IN THE NORTH TO NORTHEAST FACING SLOPES
AND GENERALLY WEST OF BILLINGS...WITH LESSER AMOUNTS EAST OF
BILLINGS.
GENERAL CONSENSUS OF MODELS IS FOR A MORE CONDENSED
PASSAGE...WITH SLOWER MOVEMENT OF THE SYSTEM EASTWARD...REACHING
BILLINGS AROUND NOON AND SPREADING INTO MILES CITY LATE THIS
EVENING...AND EXITING BY WEDNESDAY MORNING. INDICATIONS ARE STILL
THAT SNOW SHOULD BE PRETTY HEAVY TO START IN BILLINGS...ONCE THE
BRUNT OF THE SYSTEM ARRIVES...WITH 0.25 INCHES QPF. SO...CHANGED
MORNING SNOW TO SHOWERS FROM BILLINGS EAST TO INDICATE TRANSITION
TO STEADY HEAVIER SNOW...AND KEPT QPF AND SNOW AMOUNTS IN TACT. OF
GREATER CONCERN THROUGH THE PERIOD IS CONTINUED TREND OF SOME
DEGREE OF SPLITTING OF THE SYSTEM...WITH ENERGY TRANSFERRING SOUTH
INTO BOWLING BALL LOW AS IT DEEPENS OVER NEBRASKA. THIS ALLOWS
THE BULK OF THE ENERGY TO ALL BUT MISS THE EASTERN ZONES...WITH
EXCEPTION OF MAINLY WRAP- AROUND TYPE SNOW. THESE INDICATIONS OF
SPLITTING PROMPTED PARING BACK OF SNOW AMOUNTS IN THE EAST FOR THE
SYSTEM. ADDITIONALLY...TIMING IS AN ISSUE...WITH PRECIP NOT
PROGGED INTO THE EASTERN THIRD OF THE CWA UNTIL CLOSER TO MIDNIGHT
TONIGHT IF MODELS ARE CORRECT. THEREFORE...HAVE CHOSEN TO CONTINUE
WITH WATCH IN THE EAST TO ALLOW FOR ANOTHER LOOK AT TIMING AND
SNOW AMOUNTS BEFORE DECISION ON ADVISORY OR WARNING. GILSTAD
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
NORTHWEST FLOW ALOFT WEDNESDAY AND THURSDAY FOLLOWED BY A
FLATTENING RIDGE THAT MOVES INTO THE AREA ON FRIDAY AND
TRANSITIONS TO A FAST SOUTHWEST FLOW ALOFT ON SATURDAY WITH THIS
FLOW BECOMING MORE UNSETTLED BY SUNDAY.
CLIPPER SYSTEM IN THE NORTHWEST FLOW ON WEDNESDAY BRING ANOTHER
SHOT OF SNOW FOR THE REGION BUT ITS A BRIEF ROUND SO ADDITIONAL
ACCUMULATIONS WILL BE MINIMAL. COLDER AIR GETS PULLED INTO THE
AREA BEHIND THIS SYSTEM WHICH WILL WORK WITH THE SNOW COVER TO
YIELD THE COLDEST TEMPERATURES OF THE WEEK ON THURSDAY WITH
READINGS 10 TO 15 DEGREES BELOW NORMAL.
AS THE FLOW BECOMES WESTERLY ON FRIDAY TEMPERATURES MODERATE AND
WINDS WILL INCREASE ESPECIALLY FOR THE GAP FLOW AREAS. COULD BE
SOME AREAS OF BLOWING SNOW BUT IT SEEMS LIKE A SHORT WINDOW GIVEN
HOW QUICKLY TEMPERATURES WANT TO CLIMB ABOVE FREEZING. SATURDAY
WILL BE EVEN WARMER WITH NEAR FREEZING LOWS CONTRIBUTING STRONGLY
TO SNOW MELT. A SLOW COOLING TREND EXPECTED FOR SUNDAY AND MONDAY.
WITH INCREASING MOUNTAIN SNOW SHOWERS. BORSUM
&&
.AVIATION...
SOUTHEAST MONTANA INCLUDING KMLS AND KBHK WILL SEE LOW CLOUDS AND
FOG UNTIL NOON WITH THE WESTWARD EXTENT OF THESE CLOUDS AND FOG
NEAR HYSHAM. THESE AREAS COULD SEE IFR TO LIFR CONDITIONS WITH
IMPROVEMENT THIS AFTERNOON.
SNOW OVER WESTERN PORTIONS OF SOUTH CENTRAL MONTANA EARLY THIS
MORNING WILL MOVE EAST BRINGING IFR TO LIFR CONDITIONS. THE SNOW
SHOULD REACH KSHR AND KBIL BETWEEN 1800 AND 2000 UTC. SNOW WILL
COVER ALL OF THE REGION THIS EVENING WITH WIDESPREAD LIFR
CONDITIONS. BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 033 021/027 013/024 007/020 004/033 029/044 029/036
+/S +6/S 23/J 21/B 11/E 11/B 11/E
LVM 031 014/025 012/021 003/020 013/039 035/044 030/037
+/S +4/S 33/J 31/B 12/J 11/N 32/J
HDN 036 021/030 009/027 003/022 902/030 021/045 026/039
9/S +7/S 34/J 21/E 11/B 11/B 12/W
MLS 036 022/030 010/023 001/014 909/022 015/041 023/037
7/S 97/S 42/J 21/E 11/B 11/B 11/B
4BQ 038 023/029 013/022 007/017 901/027 021/044 023/040
5/S 99/S 62/J 21/E 11/B 11/B 11/B
BHK 033 019/028 014/021 006/015 904/023 014/041 021/037
2/S 77/S 53/J 21/B 11/U 11/B 11/B
SHR 036 018/026 013/024 007/022 003/034 022/047 023/039
8/S ++/S 62/J 22/J 11/B 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WARNING IN EFFECT UNTIL 6 PM MST TUESDAY FOR
ZONES 28-29-34-35-39>42-56-63>68.
WINTER STORM WARNING IN EFFECT FROM NOON TODAY TO MIDNIGHT
MST TUESDAY NIGHT FOR ZONES 30>32-36-38-57-58.
WINTER STORM WATCH IN EFFECT FROM THIS AFTERNOON THROUGH LATE
TUESDAY NIGHT FOR ZONES 33-37.
WY...WINTER STORM WARNING IN EFFECT FROM NOON TODAY TO MIDNIGHT
MST TUESDAY NIGHT FOR ZONES 98-99.
&&
WEATHER.GOV/BILLINGSThe national radar mosaic for the moment the first event began.
15 winter storm. Local standard time, as filed.
Snowfall of 6-12 inches was reported across the area.
Snowfall of 6-15 inches was reported across the area.
Snowfall of 5 inches was reported, as well as, sustained winds 30-35 mph with gusts to 40 mph.
Snowfall amounts of 7 to 14 inches were reported across the area.
Snowfall amounts ranged from 6 to 18 inches.
Snowfall of 6 inches was reported across the area.
Snowfall amounts around 14 inches were reported.
Placer Basin Snotel received around 16 inches of snow.
Snowfall of 6-15 inches was reported across the area.
Ryegate received 6 inches of snow.
Snowfall of 7-15 inches was received across the area.
Snowfall of 6 to 11 inches was reported across the area.
Snowfall of 6 to 10 inches was reported across the area.
Snowfall of 6-9 inches was reported across the area.
Snowfall around 6 inches was reported across the county.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2015Every state in 2015This day in weather historyWarnings in Montana, December 2015
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: 609694, 609695, 609700, 610408, 610409, 610411, 610413, 610414, 609692, 609688, 609690, 609691, 609685, 609686, 609693.