Bands of moderate to heavy snow, associated with a strong upper level jet, formed over the southern Front Range Foothills, Palmer Divide and southern Denver suburbs. 5 inches at Evergreen and Louviers; 7 inches, 5 miles south-southwest of Arapahoe Park; with 4 to 6 inches elsewhere.
Every event with a place to put it; 4 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.
Bands of moderate to heavy snow, associated with a strong upper level jet, formed over the southern Front Range Foothills, Palmer Divide and southern Denver suburbs. Storm totals included: 10 inches, 2 miles west-northwest of Highlands Ranch and Kiowa; 9.5 inches near Castle Rock and Littleton; 8 inches at Aspen Springs and Marston Reservoir; 7.5 inches at Evergreen and Louviers; 7 inches, 5 miles south-southwest of Arapahoe Park; with 4 to 6 inches elsewhere.
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 Feb 23, 2:43 AM MST, 1 hour 47 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER/BOULDER CO 243 AM MST THU FEB 23 2012 .SHORT TERM...FRONT HAS ARRIVED A BIT EARLIER...PROBABLY DUE TO ACCELERATION FROM CONVECTIVE OUTFLOW. BANDED SNOW WAS QUICKLY DROPPING SOUTHWARD AND WILL CONTINUE TO PUSH SOUTH ACROSS THE PALMER DIVIDE THROUGH THE EARLY MORNING HOURS. EXPECT ONE HALF TO 2 INCHES OF SNOW ON AVERAGE WITHIN A 1-2 HOUR PERIOD...AND THEN DECREASING SNOW THEREAFTER. THERE WILL BE SOME SLUSH/SNOW COVERED AREAS ESPECIALLY DURING PERIOD OF HEAVIEST SNOWFALL BEFORE THE MAIN MORNING COMMUTE. SOME BRIDGES/OVERPASSES WILL LIKELY REMAIN SLUSHY OR BECOME ICY AS TEMPS FALL INTO THE UPPER 20S...BUT WARM PAVEMENT TEMPS SHOULD HELP MELT THE MAIN ROADS AFTER SNOW INTENSITY DECREASES. A FEW SHOWERS MAY LINGER ON THE PLAINS INTO THE LATE MORNING/AFTERNOON HOURS WITH AN UNSTABLE AIRMASS...BUT DO NOT ANTICIPATE ANY MEANINGFUL SNOWFALL GIVEN DRIER NORTHWEST BOUNDARY LAYER FLOW AND SUBSIDENCE BUILDING IN. IN THE MOUNTAINS...WILL CONTINUE THE WINTER STORM WARNINGS WITH BLIZZARD CONDITIONS AT TIMES ESPECIALLY EARLY THIS MORNING DURING THE HEAVIEST SNOWFALL. MOUNTAIN CAMS SHOW RATHER SEVERE WINTER WEATHER WITH CONSIDERABLE BLOWING/HEAVY FALLING SNOW. CONDITIONS WILL GRADUALLY IMPROVE LATER THIS MORNING AND AFTERNOON WITH PRECIPITATION BECOMING MORE SHOWERY AND DECREASING IN INTENSITY. WARNINGS WILL LIKELY BE ALLOWED TO EXPIRE AT 11 AM OR DOWNGRADED TO AN ADVISORY BASED ON OBSERVATIONS LATER THIS MORNING...AS WE STILL EXPECT SOME BUT NOT HEAVY SNOW ACCUMULATION INTO THE EVENING HOURS. WITH REGARD TO THE HIGH WIND WARNINGS...WILL CANCEL THE REMAINING WIND HIGHLIGHTS AS WINDS WILL DECREASE AFTER THE FROPA. AIRMASS DRIES LATER TONIGHT BRINGING A CONTINUED DECREASE IN MOUNTAIN SNOWFALL AND CLEARING SKIES TO THE PLAINS. .LONG TERM...A FLAT UPPER LEVEL RIDGE WILL BUILD OVER THE AREA ON FRI WITH THE FLOW BECOMING MORE WNW. CROSS-SECTIONS SHOW A DRY AIRMASS THRU FRI NIGHT. MEANWHILE WILL STILL SEE SOME GUSTY WINDS IN THE MTNS...FOOTHILLS AND OVER THE NERN PLAINS BUT SPEEDS WILL REMAIN HIGHLIGHT CRITERIA. HIGHS ON FRI WILL BE IN THE UPPER 30S TO LOWER 40S ACROSS NERN CO. ON SAT THE FLOW ALOFT WILL BECOME MORE WSW AS ANOTHER UPPER LEVEL TROUGH APPROACHES THE AREA. WINDS WILL INCREASE IN THE MTNS AND FOOTHILLS THROUGH THE DAY WITH SOME GUSTY SOUTHWEST WINDS OVER THE PLAINS BY AFTN. OVERALL SET UP IS NOT REAL FAVORABLE FOR WIDESPREAD HIGHS WINDS IN THE MTNS AND FOOTHILLS THRU SAT AFTN EXCEPT POSSIBLE OVER THE HIGHER TERRAIN OF ZONES 33 ANMD 35. MEANWHILE CROSS-SECTIONS SHOW BEST MOISTURE WILL NOT AFFECT THE MTNS UNTIL SAT NIGHT SO WILL ONLY MENTION LOW POPS FOR SAT AFTN. HIGHS SHOULD RISE BACK INTO THE MID 50S TO AROUND 60 ON SAT ACROSS NERN CO DUE TO SWLY LOW LVL FLOW. FOR SAT NIGHT INTO SUN THE MAIN UPPER LEVEL TROUGH WILL SWING ACROSS THE NRN AND CNTRL ROCKIES. AS THIS TROUGH MOVES ACROSS SNOW SHOULD INCREASE IN THE MTNS SAT NIGHT AND LINGER THRU SUN MORNING BEFORE DECREASING BY MIDDAY. MEANWHILE LOOKS LIKE ANOTHER HIGH WIND EVENT WILL BE POSSIBLE FM THE FOOTHILLS ACROSS PORTIONS OF THE PLAINS LATE SAT NIGHT THROUGH SUN MORNING AS WELL ALTHOUGH CURRENT FCST WIND SPEEDS ARE NOT AS STG AS THE MOST RECENT EVENT. HIGHS ON SUN WILL BE COOLER ACROSS NERN CO WITH READINGS DROPPING BACK INTO THE MID 30S TO LOWER 40S. CURRENT CROSS-SECTIONS SHOW VERY LITTLE MOISTURE OVER NERN CO SAT NIGHT THRU SUN SO WILL NOT MENTION ANY POPS. BY MON THE FLOW ALOFT WILL BECOME MORE SWLY AS ANOTHER UPPER LEVEL TROUGH DEVELOPS OVER THE WRN US. CROSS-SECTIONS SHOW MOISTURE INCREASING IN THE MTNS BY AFTN SO WILL MENTION A CHC OF SNOW SHOWERS DUE TO IMPOVING LAPSE RATES. OVER NERN CO A SFC LOW WILL DEVELOP OVER SRN COLORADO BY AFTN A CDFNT ATTEMPTS TO MOVE INTO THE AREA BY LATE AFTN OR MON EVENING. FOR NOW WILL MENTION SOME LOW POPS IN AND NR THE FOOTHILLS FOR MON AFTN. WILL KEEP HIGHS IN MAINLY THE 30S ACROSS NERN CO. FOR MON NIGHT INTO TUE BOTH THE GFS AND ECMWF MOVE AN UPPER LEVEL TROUGH QUICKLY ACROSS THE AREA WHILE THE CANADIEN IS ABOUT A DAY SLOWER. AT THIS POINT WILL TREND WITH THE ECMWF AND GFS WITH TIMING. MEANWHILE THE GFS AND ECMWF SHOW DIFFERENT SFC PATTERNS FM MON NIGHT INTO TUE. THE GFS SHOWS A SFC LOW OVER SWRN KS AS A COLD FNT MOVES ACROSS NERN CO WHILE THE ECMWF SHOWS MORE OF AN INVERTED SFC TROUGH. THUS THE GFS WOULD PRODUCE A BETTER CHC OF SNOW FM THE FOOTHILLS ACROSS THE NERN PLAINS WHILE THE EMCWF WOULD BE LESS FAVORABLE. AT THIS POINT WILL LEAVE LOWER END CONSENSUS POPS DUE TO ALL OF THE UNCERTAINTY ACROSS NERN CO AND HAVE BEST CHC IN THE MTNS. HIGHS WILL REMAIN COLD ON TUE WITH READINGS IN THE 30S ACROSS NERN CO. BY WED THE UPPER LEVEL TROUGH WILL BE EAST OF THE AREA WITH DRIER AIR SPREADING ACROSS ALONG WITH MODERATING TEMPERATURES. && .AVIATION...SNOW AND IFR/LIFR CONDITIONS WILL PERSIST TIL AROUND 12Z AND THEN DECREASE FROM NORTH TO SOUTH AS MAIN BAND OF SNOW MOVES SOUTH. A QUICK INCH OR TWO OF SNOW IS EXPECTED WITH THIS BAND IN THE PRE-DAWN HOURS. OTHERWISE...SOME LIGHT SNOW SHOWERS MAY LINGER TIL 15Z OR SO WITH CEILINGS THEN LIFTING TO VFR BY 18Z. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 11 AM MST THIS MORNING FOR COZ031-033-034. && SHORT TERM...BARJENBRUCH LONG TERM....RPK AVIATION...BARJENBRUCH
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1104 AM MST WED FEB 22 2012 COZ030>051-231300- 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- 1104 AM MST WED FEB 22 2012 ...HIGH WIND WARNING FRONT RANGE MOUNTAINS...FOOTHILLS...AND NEARBY PLAINS WEST OF I-25 TIL 5 AM THURSDAY... ...WINTER STORM WARNING NORTHERN GORE AND PARK RANGE UNTIL 11 AM THURSDAY... ...WINTER WEATHER ADVISORY NORTHERN FRONT RANGE MOUNTAINS UNTIL 11 AM THURSDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT ACTIVE WEATHER WILL CONTINUE OVER NORTH CENTRAL COLORADO AND ALONG THE FRONT RANGE FOOTHILLS THROUGH TONIGHT. STRONG WINDS ARE EXPECTED TO CONTINUE THROUGH TONIGHT AS A STRONG UPPER LEVEL JET STREAM REMAINS IN PLACE OVER NORTHERN COLORADO. MOISTURE IS EXPECTED TO INCREASE OVER THE MOUNTAINS LATER THIS EVENING WHICH WILL BRING SNOWFALL BACK INTO THE WEATHER MIX FOR THE MOUNTAIN AREAS AS THE WIND CONTINUES. MODERATE SNOWFALL AMOUNTS ARE EXPECTED IN THE MOUNTAIN AREAS OVERNIGHT WHICH WILL COMBINE WITH THE WINDY CONDITIONS TO PRODUCE HAZARDOUS TRAVEL CONDITIONS DUE TO BLOWING AND DRIFTING SNOW. LATE TONIGHT...A COLD FRONT WILL MOVE OVER THE NORTHEAST PLAINS...BRINGING COLDER TEMPERATURES. AREAS OF SNOW WILL ALSO BE POSSIBLE OVER THE I-25 CORRIDOR BY THURSDAY MORNING. LIGHT ACCUMULATIONS OF SNOW WILL BE POSSIBLE. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY SNOW WILL GRADUALLY DECREASE ACROSS THE MOUNTAINS AND PLAINS THURSDAY BEHIND THE PASSAGE OF A FAST MOVING UPPER LEVEL DISTURBANCE. IN THE MOUNTAINS...ADDITIONAL SNOWFALL AMOUNTS OF 2 TO 6 INCHES CAN BE EXPECTED THURSDAY MORNING...AND STRONG WINDS WILL PRODUCE CONSIDERABLE BLOWING SNOW AND HAZARDOUS DRIVING CONDITIONS. ON THE PLAINS...A BAND OF SNOW JUST BEHIND A COLD FRONT MAY BRING A QUICK INCH OF SNOW FOR THE THURSDAY MORNING COMMUTE. DRY CONDITIONS ARE EXPECTED FRIDAY THROUGH SATURDAY WITH WARMING TEMPERATURES. FROM SUNDAY THROUGH TUESDAY...AN UNSETTLED WEATHER PATTERN MOVES IN WITH A CHANCE OF SNOW...MAINLY FOR THE MOUNTAINS. TEMPERATURES SHOULD DROP BELOW SEASONAL NORMALS ONCE AGAIN. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. DANKERS/RJK
The national radar mosaic for the moment the first event began.
3 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 2012Every state in 2012This day in weather historyWarnings in Colorado, February 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: 365997, 365999, 366000, 366001.