A storm system brought periods of moderate to heavy snow to parts of the North Central Mountains, Front Range Foothills, Urban Corridor with blizzard conditions developing over the parts of the Northeast Plains of Colorado. The combination of snow and wind reportedly reduced the visibilities to just a few hundred feet at times, and resulted in several road closures.
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 BOU wrote it up.
A storm system brought periods of moderate to heavy snow to parts of the North Central Mountains, Front Range Foothills, Urban Corridor with blizzard conditions developing over the parts of the Northeast Plains of Colorado. The combination of snow and wind reportedly reduced the visibilities to just a few hundred feet at times, and resulted in several road closures. Across eastern Elbert, Lincoln, Logan, Phillips, Sedgwick and Washington Counties, gusty northerly winds ranged from 35 to 55 mph producing extensive blowing and drifting snow, ranging from 1 to 4 feet in depth. Storm totals in those areas were difficult to measure but estimated to range from 3 to 5 inches.
Road closures included: Interstate 70, east of Aurora to the Kansas Stateline; U.S. Highway 24, from Limon to Colorado Springs; Colorado Highway 94 between Punkin Center and Enoch; U.S. Highway 40/287 between Limon and Kit Carson; Colorado Highway 71 from east of Fort Morgan to Limon; U.S. Highway 34 from Brush to Yuma.
In the mountain and foothills, the heaviest amounts generally occurred north of Interstate 70. Storm totals included: 13 inches at Estes Park, 12 inches at Genesee and Red Feather Lakes, 11 inches at Glen Haven; 10.5 inches at Livermore, 9 inches, 4 miles west-southwest of Eldorado Springs; 8.5 inches at Coal Creek Canyon and near Crescent Village; 8 inches near Evergreen, 7 inches at Drake and Bear Lake; with 6 inches at Eldora Ski Area, Idaho Springs, Grandby, Gross Reservoir and Nederland.|Along the Urban Corridor and adjacent plains, lesser storm totals from 1 to 4 inches were observed.
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 Denver/Boulder, CO wrote its last area forecast discussion before the first event at Dec 18, 8:21 PM MST, 3 hours 39 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER/BOULDER CO 821 PM MST TUE DEC 18 2012 .UPDATE...SOME MINOR ADJUSTMENTS REGARDING SNOW AMOUNTS BASED OFF THE LATEST NAM12 00Z RUN. PRIMARILY THE FOOTHILLS OF LARIMER COUNTY...OTHERWISE THE OVERALL FCST STILL LOOKS GOOD. THERE WAS A GOOD ENHANCED BAND OF SNOWFALL THAT PRODUCED 1-2 INCHES AROUND FORT COLLINS EARLIER THIS EVENING...THEN IT SHIFTED TO THE NORTH AND WEST INTO THE FOOTHILLS. WILL CONTINUE WITH THE TIMING ALREADY IN THE GRIDS WITH MOST OF THE SNOWFALL DEVELOPING ALONG THE FRONT RANGE LATE TONIGHT THEN INCREASING WEDNESDAY MORNING. THE LATEST MDL OUTPUT GENERATED UP TO 12 INCHES POSSIBLE IN THE FOOTHILLS OF LARIMER COUNTY. ALONG THE URBAN CORRIDOR GENERALLY 2-5 INCHES STILL LOOKS GOOD...WITH ANOTHER AREA OF HEAVY SNOW (6-8 INCHES) IN ZONES 48..50 AND 51. && .AVIATION...SUSPECT NORTHEAST TO NORTHERLY WINDS WILL CONTINUE THROUGH THIS EVENING...THEN NORTHERLIES INCREASING AFTER 06Z. MDLS STILL GENERATING 2 TO 4 INCHES OF SNOW AT KDEN...WITH AREAS OF BLOWING SNOW DEVELOPING AFTER 12Z. OVERALL TIMING IN THE TAFS LOOKS GOOD AT THIS TIME SO ANY CHANGES IN THE UPCOMING TAFS SHOULD BE MINOR. CONDITIONS SHOULD IMPROVE WEDNESDAY AFTERNOON. && .PREV DISCUSSION... /ISSUED 342 PM MST TUE DEC 18 2012/ SHORT TERM...MOUNTAIN WEB CAMS SHOW SNOW HAS DECREASED MOST AREAS AS FLOW ALOFT BECOMES SOUTHWEST AHEAD OF APPROACHING TROUGH. ELSEWHERE...MID AND HIGH LEVEL CLOUDS ON THE INCREASE AS MOISTURE SPREADS INTO REGION. MODELS SIMILAR IN BRINGING TROUGH ACROSS GREAT BASIN THIS EVENING WITH INCREASING MID LEVEL ASCENT AND INSTABILITY. SHOULD BEGIN TO SEE SNOW INCREASE ONCE AGAIN... ESPECIALLY AFTER MIDNIGHT WHEN 700 MB LOW MOVES INTO WESTERN COLORADO AND FLOW ALOFT BECOMES WESTERLY. SHOULD SEE A GOOD SHOT OF SNOW WITH THE INCREASING ASCENT AND FAVORABLE LAPSE RATES. WILL ISSUE AN ADVISORY FOR SNOW FOR THE MOUNTAINS...BEGINNING AT MIDNIGHT. ACROSS PLAINS...SURFACE LOW TO DEEPEN TONIGHT AHEAD THE APPROACHING LOW WITH WINDS BECOMING NORTHERLY AFTER 06Z. AIRMASS TO GRADUALLY MOISTEN AS DEEPER MOISTURE SPREADS INTO AREA. BEGINNING TO SEE SOME ECHOES ACROSS LARIMER AND NORTHWESTERN WELD COUNTIES. LATEST MODELS SHOW MOST OF THE SNOW DEVELOPING AFTER 06Z..THOUGH THE RAP HOLDING OFF UNTIL AFTER 09Z WHICH MAY BE A BIT SLOW. AS WINDS BECOME NORTHERLY...SHOULD SEE SNOW COVERAGE INCREASE AND BEGIN TO SPREAD SOUTH BY 12Z. UPPER LOW TO MOVE ACROSS THE STATE DURING THE MORNING WITH GOOD QG VERTICAL VELOCITIES AND INCREASING LAPSE RATES. LATEST MODELS HAVE BEEN INDICATING LESS SNOW FOR THE PLAINS...BUT MAY BE OVERDONE GIVEN THE MID LEVEL ASCENT. A FEW LOCATIONS COULD SEE SNOW FALL RATES OF 1/2 TO 1 INCH PER HOUR DURING THE PERIOD OF GREATEST ASCENT DURING THE MORNING. WILL UPGRADE THE WINTER STORM WATCH TO A SNOW AND BLOWING SNOW ADVISORY FOR MUCH OF THE PLAINS. WILL BEGIN THIS HILITES AT 08Z...MAINLY TO ACCOUNT FOR THE MORNING RUSH. WILL ALSO ISSUE A SNOW ADVISORY FOR THE FOOTHILLS BEGINNING AT 08Z AS MODELS SHOW DEEP UPSLOPE TO AROUND 600 MB. ACROSS THE FAR EASTERN PLAINS...BEST CHANCE FOR SNOW TO BE AROUND 15Z. THOUGH SNOW AMOUNTS MAY BE A BIT LIGHT...THE GUSTY WINDS WILL PROVIDE FOR BLIZZARD CONDITIONS FOR ZONES 46..47 AND 49 WITH LIMITED VISIBILITES. WILL ISSUE A BLIZZARD WARNING FOR THOSE ZONES BEGINNING AT 15Z. WILL ALSO INCLUDE ZONES 48..50..51 AS WELL AS 41. SOME ROAD CLOSURES WILL CERTAINLY BE POSSIBLE. ACROSS THE MOUNTAINS...WILL CONTINUE THE ADVISORY THROUGH THE AFTERNOON. SNOW WILL PROBABLY BE ON THE DECREASE AS MOISTURE AND DYNAMICS DECREASE. TOTAL SNOW ACCUMULATIONS LOOK TO BE FROM 3 TO 8 INCHES ACROSS THE PLAINS AND FOOTHILLS...HIGHEST NEAR THE WYOMING BORDER. ACROSS THE MOUNTAINS...6 TO 14 INCHES CAN BE EXPECTED. LONG TERM...MODELS SHOW THE UPPER TROUGH AXIS OVER THE EASTERN BORDER AT 00Z WEDNESDAY EVENING. STRONG NORTHWESTERLY FLOW ALOFT IS PROGGED WEDNESDAY NIGHT. ON THURSDAY AND THURSDAY NIGHT...AN UPPER RIDGE IS PROGGED TO MOVE ACROSS COLORADO WITH FAIRLY STRONG WEST- NORTHWESTERLY FLOW ALOFT. THURSDAY NIGHT AND FRIDAY ARE PROGGED TO HAVE FAIRLY WEAK ZONAL FLOW ALOFT. BY FRIDAY NIGHT...THE FLOW ALFOT IS WEST-SOUTHWESTERLY IN DIRECTION. THE QG VERTICAL VELOCITY FIELDS HAVE DOWNWARD SYNOPTIC SCALE ENERGY PROGGED FOR THE CWA WEDNESDAY NIGHT INTO THURSDAY EVENING. THE REST OF THE THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE ENERGY IS BENIGN. THE LOW LEVEL WIND AND PRESSURE FIELDS SHOW THE BOUNDARY LAYER FLOW TO BECOME DOWNSLOPING EARLY WEDNESDAY EVENING. BY 06Z WEDNESDAY NIGHT... WESTERLY WINDS PREVAIL OVER THE MOUNTAINS...FOOTHILLS AND WESTERN PLAINS...WITH FAIRLY STRONG NORTHWESTERLIES THE FURTHER EAST TO GO TO THE COLORADO BORDER. DOWNSLOPING IS PROGGED TO CONTINUE THURSDAY AND FRIDAY...BUT AT LESSER SPEEDS. FOR MOISTURE...THERE IS STILL SOME OVER THE EASTERN FORECAST AREA EARLY THURSDAY EVENING...BUT ALL THE MODELS DRY THINGS OUT RAPIDLY AND BY 06Z WEDNESDAY NIGHT...PRECIPATION SHOULD BE OVER EVERYWHERE. MOISTURE IS QUITE SPARSE THURSDAY THROUGH FRIDAY NIGHT. THERE IS NO MEASURABLE PRECIPITATION NOTED ON THE QPF FIELDS WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...ALL FIVE PERIODS. FOR POPS...WILL DECREASE EVERYTHING RAPIDLY WEDNESDAY EVENING...THEN NO POPS FROM 06Z WEDNESDAY NIGHT THROUGH FRIDAY. WILL LINGER SOME BLOWING SNOW OVER APPROPRIATE AREAS WEDNESDAY NIGHT. AS FAR AS HIGHLIGHTS GO... WILL GO WITH THE SHORT TERM FORECASTER. FOR TEMPERATURES... THURSDAY HIGHS ARE 6-9 C WARMER THAN WEDNESDAY'S. MOS GUIDANCE VALUES MAY BE TO HIGH...ESPECIALLY FIGURING WE WILL LIKELY HAVE A SNOW COVER IN PLACE OVER MUCH OF THE CWA. FRIDAYS'S HIGH COME UP ANOTHER 2-4 C FROM THURSDAY'S. FOR THE LATER DAYS...SATURDAY THROUGH TUESDAY...MODELS HAVE WEST-SOUTHWESTERLY FLOW ALOFT OVER THE CWA SATURDAY INTO MONDAY. THE ECMWF BRINGS AN UPPER TROUGH ACROSS LATE MONDAY AND MONDAY NIGHT. THE GFS IS MUCH SLOWER WITH THE SYSTEM. BOTH MODELS HAVE LITTLE MOISTURE OVER THE WEEKEND. BUT BY SUNDAY NIGHT...MOISTURE IS ON THE INCREASE. BOTH MODELS DO SHOW A PRETTY COLD AIRMASS TO MOVE INTO COLORADO WITH THE UPPER TROUGH MONDAY OR TUESDAY...DEPENDING. THERE IS ALSO UPSLOPE FOR THE PLAINS AND FOOTHILLS. WILL GO WITH MINOR POPS RIGHT NOW AND CONTINUE TO WATCH THE EVOLUTION OF THIS FEATURE. AVIATION...EASTERLY WINDS TO SHIFT TO THE NORTH AROUND 06Z AS A COLD FRONT MOVES SOUTH ACROSS THE PLAINS. SHOULD SEE CEILINGS GRADUALLY LOWER...WITH CEILINGS AROUND 6000 FEET POSSIBLE. NOT EXPECTING SNOW TO DEVELOP UNTIL AFTER 06Z WITH MVFR CONDITIONS BY 09Z. IFR CONDITIONS TO FROM 12Z TO 19Z DUE TO SNOW AND BLOWING SNOW AS WELL AS LOW CEILINGS. SNOW TO DECREASE AFTER 19Z BUT GUSTY WINDS TO CONTINUE. MVFR CONDITIONS TO PREVAIL WITH OCCASIONAL IFR CONDITIONS. TOTAL SNOW ACCUMULATIONS OF 2 TO 4 INCHES EXPECTED...MAINLY DURING THE 12Z TO 18Z TIME FRAME. && .BOU WATCHES/WARNINGS/ADVISORIES... BLIZZARD WARNING FROM 8 AM TO 8 PM MST WEDNESDAY FOR COZ041- 046>051. WINTER WEATHER ADVISORY FROM 3 AM TO 5 PM MST WEDNESDAY FOR COZ035-036-038>040-042>045. WINTER WEATHER ADVISORY UNTIL 5 PM MST WEDNESDAY FOR COZ031-033- 034. && SHORT TERM...COOPER LONG TERM....RJK AVIATION...COOPER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER/BOULDER CO 1050 AM MST TUE DEC 18 2012 COZ030>051-191800- JACKSON COUNTY BELOW 9000 FEET- WEST JACKSON AND WEST GRAND COUNTIES ABOVE 9000 FEET- GRAND AND SUMMIT COUNTIES BELOW 9000 FEET- SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/ NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET- SOUTH AND SOUTHEAST GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/ GILPIN/CLEAR CREEK/SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE 9000 FEET-LARIMER AND BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET- JEFFERSON AND WEST DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR CREEK/NORTHEAST PARK COUNTIES BELOW 9000 FEET- CENTRAL AND SOUTHEAST PARK COUNTY- LARIMER COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY- BOULDER AND JEFFERSON COUNTIES BELOW 6000 FEET/WEST BROOMFIELD COUNTY- NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE COUNTIES/EAST BROOMFIELD COUNTY- ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET- NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD COUNTY-MORGAN COUNTY- CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES- NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN COUNTY- SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN COUNTY- LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS COUNTY- 1050 AM MST TUE DEC 18 2012 ...ANOTHER WINTER STORM HEADED FOR COLORADO TONIGHT AND WEDNESDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT LIGHT SNOW WILL CONTINUE ACROSS THE MOUNTAINS ALONG WITH GUSTY WESTERLY WINDS. ADDITIONAL SNOW ACCUMULATES OF 1 TO 4 INCHES CAN BE EXPECTED...MAINLY ALONG WEST FACING SLOPES. THE GUSTY WINDS WILL CREATE SOME BLOWING SNOW OVER THE HIGHER MOUNTAIN PASSES. THE SNOW WILL INCREASE AGAIN ACROSS THE MOUNTAINS DURING THE EVENING WITH ADDITIONAL ACCUMULATIONS OF 3 TO 6 INCHES EXPECTED BY WEDNESDAY MORNING. OVER THE NORTHEAST PLAINS...A COLD FRONT WILL PUSH SOUTHWARD AFTER MIDNIGHT. SNOW WILL DEVELOP BEFORE DAWN WITH UP TO 2 INCHES POSSIBLE. NORTHERLY WINDS WILL INCREASE THROUGH THE NIGHT AT SPEEDS OF 15 TO 25 MPH ALONG WITH COLDER TEMPERATURES. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE WINTER STORM WILL CONTINUE ON WEDNESDAY WITH SNOW...BLOWING SNOW...COLDER TEMPERATURES AND FAIRLY DECENT ACCUMULATIONS FOR MUCH OF THE FORECAST AREA. SNOWFALL AMOUNTS OVER THE PLAINS WILL RANGE FROM 2 TO 6 INCHES ON WEDNESDAY...WITH UP TO 6 INCHES OF ADDITIONAL SNOWFALL INCHES IN THE MOUNTAINS THROUGH SUNSET. WINDS COULD BE STRONG ENOUGH OVER THE NORTHEAST CORNER OF THE PLAINS FOR A PERIOD OF BLIZZARD CONDITIONS. SNOW SHOULD END BY EARLY WEDNESDAY EVENING...THEN A PERIOD OF DRIER AND WARMER WEATHER SHOULD PREVAIL THROUGH THE WEEKEND. THE NEXT WINTER STORM COULD AFFECT THE FORECAST AREA MONDAY AND TUESDAY...CHRISTMAS EVE AND CHRISTMAS DAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. HOWEVER...SNOWFALL REPORTS WILL BE APPRECIATED.
PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE DENVER CO
601 PM MST TUE DEC 18 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0527 PM SNOW 1 SE FORT COLLINS 40.55N 105.05W
12/18/2012 E1.5 INCH LARIMER CO TRAINED SPOTTER
SNOW FELL IN 45 MINUTES
0547 PM SNOW 2 SSE ESTES PARK 40.34N 105.51W
12/18/2012 M2.5 INCH LARIMER CO TRAINED SPOTTER
SNOW FALLING A RATE OF ONE HALF INCH PER HOUR
0555 PM SNOW 1 E FORT COLLINS 40.56N 105.05W
12/18/2012 M2.5 INCH LARIMER CO TRAINED SPOTTER
SNOW HAS ENDED
&&
FCOOPERPRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DENVER CO
855 PM MST TUE DEC 18 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0527 PM SNOW 1 SE FORT COLLINS 40.55N 105.05W
12/18/2012 E1.5 INCH LARIMER CO TRAINED SPOTTER
SNOW FELL IN 45 MINUTES
0547 PM SNOW 2 SSE ESTES PARK 40.34N 105.51W
12/18/2012 M2.5 INCH LARIMER CO TRAINED SPOTTER
SNOW FALLING A RATE OF ONE HALF INCH PER HOUR
0555 PM SNOW 1 E FORT COLLINS 40.56N 105.05W
12/18/2012 M2.5 INCH LARIMER CO TRAINED SPOTTER
SNOW HAS ENDED
0840 PM SNOW 2 SSE ESTES PARK 40.34N 105.51W
12/18/2012 E4.5 INCH LARIMER CO TRAINED SPOTTER
LIGHT SNOW AT THE TIME OF THE OBSERVATION
&&
FCOOPERThe national radar mosaic for the moment the first event began.
9 winter weather, 1 blizzard. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2012Every state in 2012This day in weather historyWarnings in Colorado, December 2012
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: 416785, 416783, 416784, 416786, 416787, 416789, 416790, 416791, 416792, 416793.