Another round of snow developed in and near the Front Range Foothills. The heaviest snowfall occurred in the foothills of Boulder and northern Jefferson Counties.
Every event with a place to put it; 3 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.
Another round of snow developed in and near the Front Range Foothills. The heaviest snowfall occurred in the foothills of Boulder and northern Jefferson Counties. Storm totals included: 13 inches, 7 miles southwest of Boulder; 10.5 inches, 4 miles east-northeast of Nederland; 10 inches at Genesee; 9.5 inches, 4 miles west-northwest of Boulder; 9 inches at Gross Reservoir and 4 miles east of Pinecliffe; 8.5 inches at Buckhorn Mountain. Around the Urban Corridor, storm totals ranged from 3 to 8 inches, heaviest in and around Boulder.
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 2, 8:20 PM MST, 5 hours 40 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 820 PM MST FRI DEC 2 2011 .UPDATE...HAVE ISSUED WINTER WEATHER ADVISORIES FOR THE PALMER AND I70 CORRIDOR EAST OF DENVER DUE TO THE SNOW AMOUNTS OF 2 TO 5 INCHES COMBINED WITH NORTH WINDS GUSTING TO 30 MPH ON TUESDAY. HAVE ALSO ISSUED AN ADVISORY FOR THE FOOTHILLS...FOR MODERATE SNOWFALL OVERNIGHT AND SATURDAY MORNING TOTALLING 3 TO 6 INCHES. && .AVIATION...THERE IS NO CHANGE FOR EXPECTED TIMING AND CONDITIONS AT AREA AIRPORTS. TOTAL SNOWFALL AT DIA IS EXPECTED TO BE AROUND 3 INCHES BY 18Z SATURDAY. && .PREV DISCUSSION... /ISSUED 230 PM MST FRI DEC 2 2011/ SHORT TERM...COLORADO IN THE LULL BETWEEN TWO SYSTEMS TODAY BUT THIS WILL ALL CHANGE AGAIN TONIGHT AND SATURDAY WITH SNOW AND COLDER TEMPERATURES MAKING A CAMEO APPEARANCE. THE UPPER LOW ACROSS ARIZONA WILL START TO EJECT AND WEAKEN AS UPSTREAM KICKER ACROSS MONTANA AND IDAHO MOVES SOUTHWARD INTO THE MEAN TROF POSITION SATURDAY MORNING. THE ASSOCIATED COLD FRONT IS NOW OVER NORTHERN WYOMING AND WILL MOVE SOUTH THIS EVENING INTO EASTERN COLORADO. THERE IS A SECONDARY SURGE STILL NORTH OF THE WYOMING BORDER WHICH HAS A GOOD 5-6MB PRESSURE RISE WITH IT. THIS WILL ENHANCE THE UPSLOPE FLOW OVER NORTHERN COLORADO LATER TONIGHT. THERE IS A MODEST AMOUNT OF QG FORCING THAT WILL MOVE ACROSS CENTRAL COLORADO LATER TONIGHT AND SATURDAY MORNING WHEN WE EXPECT THE MORE WIDESPREAD SNOW OVER THE EASTERN PLAINS ALONG WITH THE DEEPENING UPSLOPE FLOW. LOOKS LIKE THE MAX SNOW INTENSITY WILL BE CENTERED RIGHT AROUND 12Z SATURDAY OVER THE DENVER AREA. THE MODEL CONSENSUS SEEMS TO BE AROUND A 1-4 INCH SNOWFALL OVER MUCH OF THE AREA WITH A FEW MORE INCHES THAN THAT OVER THE FRONT RANGE FOOTHILLS. AT THIS TIME WON'T HAVE ANY WINTER HILITES IN PLACE AS AMOUNTS WOULD MAINLY BE LOW END CRITERIA. IF THE STORM POTENTIAL LOOKS BETTER DURING NEXT FEW SHIFTS THEN AN ADVISORY WOULDN'T BE OUT OF THE QUESTION. THE SNOW WILL DECREASE AND DIMINISH SATURDAY AFTERNOON FROM NORTH TO SOUTH AS THE MAIN FORCING SHIFTS INTO THE CENTRAL PLAINS BY LATE SATURDAY AFTERNOON. LONG TERM...SNOW AND WINDS WILL CONTINUE TO DECREASE SATURDAY NIGHT AS THE DOWNWARD MOTION MOVES OVERHEAD ON THE BACKSIDE OF THE SHORTWAVE AND 700 MB FLOW TURNS WEST TO HELP DRY THE AIRMASS OUT. TEMPERATURES SATURDAY NIGHT WILL DROP INTO THE SINGLE DIGITS TO LOWER TEENS...WITH THE MOUNTAINS LIKELY TO DIP BELOW ZERO. NORTHWEST FLOW ALOFT WILL CONTINUE SUNDAY AS YET ANOTHER SHORTWAVE MOVES OUT OF CANADA AND OVER COLORADO...PUSHING A COLD FRONT DOWN OVER THE AREA DURING THE DAY. THE MOISTURE CONTENT OF THIS SYSTEM WILL BE LESS THAN THE PREVIOUS TWO...HOWEVER TEMPERATURES WILL BE COLDER BEHIND THE FRONT CAUSING GREATER SNOW RATIOS. EXPECT SNOW TO BEGIN OVER THE NORTHERN MOUNTAINS THAT MORNING...INCREASING TO THE SOUTH THAT AFTERNOON...THEN SPREAD ONTO THE PLAINS IN THE EARLY EVENING. THOUGH THE STORM WILL STILL FOCUS MOST OF ITS ENERGY ON THE FOOTHILLS AND WESTERN PLAINS...THE UPSLOPE COMPONENT IS NOT EXPECTED TO BE AS STRONG WITH THIS SYSTEM. THEREFORE...EXPECTING THE MOUNTAINS TO RECEIVE MORE SNOW FROM THIS ONE THAN THE PREVIOUS TWO SYSTEMS. MAX TEMPERATURES WILL ONLY BE IN THE UPPER TEENS TO THE UPPER 20S ACROSS THE CWA SUNDAY...BUT EVEN COLDER MONDAY AS THE COLD POST FRONTAL AIRMASS SETTLES IN OVER THE STATE. COLD TEMPERATURES SUNDAY NIGHT WILL WARM LITTLE MONDAY WITH READINGS ABOUT 5 TO 10 DEGREES COLDER THAN SUNDAY. THE UPPER TROUGH WILL FINALLY MOVE SOUTHEAST OF THE AREA STARTING TUESDAY WITH AN UPPER RIDGE BUILDING OVERHEAD. THIS WILL BRING A WARMING AND DRYING TREND TO THE AREA AS THE COLD NORTHERLY FLOW ALOFT TRANSITIONS TO A MORE OF WEST/NORTHWESTERLY FLOW. MODELS ARE THEN BEGINNING TO SHOW A LARGE UPPER TROUGH DIPPING SOUTH OUT OF CENTRAL CANADA WHICH WILL BRING A SLIGHT COOL DOWN WITH A SLIGHT CHANCE OF SNOW AGAIN. AVIATION...LIGHT SNOW IS EXPECTED TO DEVELOP OVER THE DENVER TERMINALS AROUND MIDNIGHT OR SHORTLY AFTER...WITH THE BRUNT AND MORE WIDESPREAD SNOWFALL BETWEEN 10Z-16Z WITH LOWEST VISIBILITIES AND HIGHEST SNOW RATES EXPECTED. WITH THE SNOW...IFR AND ILS APPROACHES EXPECTED. STORM TOTAL SNOWFALL OF 2 TO 4 INCHES EXPECTED...WITH SOME DRIFTING SNOW AT KDEN/KAPA SATURDAY MORNING WITH NORTH WINDS 10-20 KNOTS. SNOWFALL RATES IN THE HEAVIER AROUND A HALF INCH PER HOUR. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 2 AM TO 2 PM MST SATURDAY FOR COZ041-045-046-049. WINTER WEATHER ADVISORY FROM 2 AM TO 11 AM MST SATURDAY FOR COZ035-036. && SHORT TERM...RTG LONG TERM....99 AVIATION...RTG
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1101 AM MST FRI DEC 02 2011 COZ030>051-031300- 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- 1101 AM MST FRI DEC 02 2011 ...MORE SNOW ON THE WAY FOR COLORADO LATER TONIGHT AND SATURDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT NORTHERN COLORADO WILL HAVE A BREAK BETWEEN WEATHER SYSTEMS TODAY WITH MOSTLY SUNNY SKIES OVER EASTERN COLORADO. THE FOG WILL CONTINUE TO DISSIPATE ACROSS WELD COUNTY BY EARLY AFTERNOON. CLOUDS WILL INCREASE OVER THE MOUNTAINS THIS AFTERNOON WITH A CHANCE OF SNOW DEVELOPING AHEAD OF THE NEXT WEATHER SYSTEM. THERE WILL ALSO BE SOME GUSTY SOUTHERLY WINDS OVER THE FAR EASTERN PLAINS WITH GUSTS UP TO 35 MPH. THE NEXT WEATHER SYSTEM WILL SPREAD SNOW ACROSS THE MOUNTAINS THIS EVENING...WITH LIGHT SNOW MOVING ONTO THE PLAINS LATER TONIGHT. IN THE HIGHER MOUNTAINS AND FRONT RANGE FOOTHILLS...2 TO 5 INCHES OF SNOW MAY FALL BY MORNING...WITH UP TO 2 INCHES POSSIBLE ELSEWHERE. NORTH WINDS GUSTING TO AROUND 30 MPH MAY CAUSE SOME DRIFTING SNOW ON THE PLAINS LATE TONIGHT. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY SNOW WILL CONTINUE THROUGH THE MORNING AND INTO THE EARLY AFTERNOON SATURDAY...ESPECIALLY IN AND NEAR THE SOUTHERN FRONT RANGE FOOTHILLS AND PALMER DIVIDE. ADDITIONAL ACCUMULATIONS IN THOSE AREAS WILL RANGE FROM 2 TO 4 INCHES. GUSTY NORTHERLY WINDS WILL PRODUCE AREAS OF BLOWING SNOW AS WELL ESPECIALLY ALONG THE PALMER DIVIDE AND EAST TO THE KANSAS BORDER. CONDITIONS ARE EXPECTED TO GRADUALLY IMPROVE FROM NORTH TO SOUTH LATE SATURDAY AFTERNOON. AFTER A BRIEF BREAK LATE SATURDAY NIGHT INTO SUNDAY...A WEAK SYSTEM WILL BRING ANOTHER ROUND OF SNOW TO THE REGION SUNDAY NIGHT AND MONDAY MORNING WITH SLIGHTLY LESSER SNOWFALL AMOUNTS AND WINDS. THOUGH THE HIGHER MOUNTAINS SHOULD RECEIVE MORE SNOW FROM THIS SYSTEM THAN FROM THE LAST TWO SYSTEMS...THE STORM WILL STILL FOCUS ON THE FOOTHILLS AND PALMER DIVIDE AREA. TEMPERATURES ARE EXPECTED TO REMAIN COLD THROUGH MONDAY...THEN WARMER AND DRY CONDITIONS TUESDAY THROUGH THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT...HOWEVER SNOWFALL REPORTS WILL BE APPRECIATED LATER TONIGHT WITH THE NEXT INCOMING SYSTEM. ENTREKIN/KRIEDERMAN
The national radar mosaic for the moment the first event began.
2 winter weather, 1 winter storm. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2011Every state in 2011This day in weather historyWarnings in Colorado, December 2011
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: 357307, 357308, 357309.