A strong upper level jet stream produced high winds in and near the Front Range mountains, foothills and adjacent plains of northeast Colorado. In Boulder, the strong winds snapped power poles and toppled trees.
Every event with a place to put it; 8 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 strong upper level jet stream produced high winds in and near the Front Range mountains, foothills and adjacent plains of northeast Colorado. In Boulder, the strong winds snapped power poles and toppled trees. As a result, about 7,000 Xcel Energy customers were without power for several hours. The high winds overturned a tractor-trailer on Foothills Highway overpass, north of Valmont Road. The driver suffered minor injuries. A parked car was totalled when it was crushed by a fallen tree near the University of Boulder. The strong winds were also responsible for two Boulder County wildfires which consumed a total of 65 acres. Colorado Department of Transportation officials closed U.S. 36 at McCaslin Boulevard in both directions after the wind caused damage to the pedestrian overpass. Metal siding from the overpass fell into highway; fortunately there were no injuries.
In total, electrical outages affected 46,000 customers along the Front Range. Damage to roofs, siding, garage doors and fences was also reported along the Urban Corridor. In Timnath, the wind knocked a power line on to the roof of the Colorado Feed and Grain building. The ensuing fire partially destroyed the building and forced the evacuation of three people. Across the northeast plains of Colorado the stronger wind gusts were more localized and over a much shorter duration.
Peak wind gusts included: 93 mph near Lyons; 88 mph at NCAR Mesa Lab; 85 mph, 2 miles southwest of Rocky Flats; 82 mph, 5 miles northwest of Boulder; 81 mph, 2 miles north of Longmont, 4 miles east-northeast of Nederland, the National Wind Technology Center and near Wondervu; 80 mph at the Junction of Highways 72 and 93; 79 mph at the Boulder Municipal Airport; 78 mph, 6 miles northwest of Boulder and atop Loveland Pass; 77 mph at Rocky Mountain Municipal Airport; 76 mph atop Berthoud Pass; 75 mph near Aspen Springs; 73 mph, 5 miles northeast of Hoyt; 70 mph at Longmont Municipal Airport; 64 mph at Erie Municipal Airport; 63 mph at Sterling; 62 mph, 8 miles south-southwest of Grover; and 60 mph, 3 miles west of New Raymer.
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 21, 8:34 PM MST, 2 hours 26 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 834 PM MST TUE FEB 21 2012 .UPDATE...STRONG NORTHWEST FLOW ALOFT TO CONTINUE OVER THE AREA TONIGHT AND ALL THE WAY THROUGH WEDNESDAY NIGHT. SATELLITE SHOWING A LARGE AREA OF MOISTURE EMBEDDED IN THE NORTHWEST FLOW OVER NORTH CENTRAL COLORADO EXTENDING NORTHWEST INTO IDAHO AND MONTANA. SNOTEL SITES OVER WESTERN JACKSON COUNTY INDICATE 5 TO 10 INCHES OF SNOW HAS FALLEN ALREADY IN THE PAST 12 HOURS. FARTHER EAST... ESTIMATE THAT 2 TO 5 INCHES HAS FALLEN IN ROCKY MOUNTAIN NATIONAL PARK AND ACROSS THE HIGH AREAS AROUND IT. MODELS INDICATE THE LIGHT TO MODERATE SNOW WILL PERSIST THROUGH WEDNESDAY MORNING. EXPECT TO SEE A PERIOD OF NO SNOW OR PERHAPS JUST LIGHT SNOW WEDNESDAY AFTERNOON AND WEDNESDAY. THEN THE FRONT PUSHES THROUGH WILL BRING REINFORCING SHOT OF SNOW LATE WEDNESDAY NIGHT AND THURSDAY. WILL UPGRADE ZONE 31 TO A WARNING AND ISSUE AN ADVISORY FOR ZONE 33. TOTAL SNOWFALL AMOUNTS MAY PUSH 3 FEET IN WESTERN JACKSON COUNTY WITH LOCALLY 18 INCHES IN ROCKY MOUNTAIN NATIONAL PARK THROUGH THURSDAY. FOR SUMMIT COUNTY AND ZONE 34...EXPECT PERIODS OF LIGHT SNOW OVER FAVORED NORTHWEST FACING SLOPES. SNOW AMOUNTS EXPECTED TO STAY BELOW ADVISORY CRITERIA...LESS THAN 6 INCHES. STRONG WINDS STILL ON TRACK FOR TONIGHT ON THROUGH WEDNESDAY NIGHT. MOVED UP THE WARNING START TIME TO NOW SINCE WINDS ARE GUSTING 60 TO 80 MPH. HIGH RESOLUTION MODELS...SHOWING THE GREAT THREAT FOR STRONG WINDS WILL OCCUR AFTER MIDNIGHT TONIGHT AND THROUGH THE DAY WEDNESDAY. THREAT FOR HIGH WINDS WILL END ONCE A COLD FRONT DROPS SOUTH ACROSS THE AREA LATE WEDNESDAY/EARLY THURSDAY MORNING. ALSO NEEDED TO INCREASE POPS FOR BEHIND THE FRONT LATE WEDNESDAY NIGHT AND THURSDAY MORNING. BOTH THE GFS AND NAM SHOW A BRIEF PERIOD OF UPSLOPE BEHIND THE FRONT. SOME MODELS ARE SHOWING SNOW FOR SNOW WITH THIS AND SOME NOT. NEED TO AT LEAST CONVEY THE MESSAGE WE COULD SEE A QUICK SHOT OF SNOW THURSDAY MORNING AND THUS MAKING FOR A SLOW COMMUTE. && .AVIATION...GUSTY WEST TO WEST-NORTHWEST WINDS WILL CONTINUE AT KDEN AND KBJC THROUGH THE NEXT 24 HOURS. GENERALLY EXPECT WEST WINDS OF 15 TO 30 KNOTS AT KDEN WITH OCCASIONALLY HIGHER GUSTS. WINDS AT KDEN WILL ALSO DECREASE AT TIMES. WHEN THEY DO...WINDS WILL SHIFT SOUTHWESTERLY. AT KBJC...WINDS WILL BE VERY STRONG WITH WINDS OF 30 TO 50 KNOTS COMMON AND OCCASIONAL GUSTS TO 70 KNOTS. KAPA WILL BE MORE PROTECTED FROM THE WINDS. LIGHT WINDS OVERNIGHT WILL INCREASE WEDNESDAY AND GUSTS TO 30 KNOTS. && .PREV DISCUSSION... /ISSUED 315 PM MST TUE FEB 21 2012/ SHORT TERM...THE NOSE OF THE STRONG NORTHERLY JET IS APPROACHING THE STATE THIS AFTERNOON AND WILL MOVE OVER THE FORECAST AREA LATER TONIGHT. THROUGH THIS AFTERNOON...THE WSR-88D HAS BEEN SHOWING SNOW RIGHT ALONG THE CONTINENTAL DIVIDE. HOWEVER...CROSS SECTIONS HAVE SHOWN A LAYER OF STABILITY OVER THE MOUNTAINS THAT HAS BEEN LIMITING SHOWER ACTIVITY ELSEWHERE IN THE HIGH COUNTRY. STABILITY ABOVE THE BOUNDARY LAYER IS FORECAST TO DIMINISH LATER THIS EVENING WHICH WILL ALLOW SNOW SHOWER ACTIVITY TO INCREASE OVER ZONES 31 AND 33. WITH ADDITIONAL SNOWFALL EXPECTED...WILL LET THE ADVISORY OVER ZONE 31 REMAIN IN PLACE. MODEL CROSS SECTIONS ALSO SHOW A MOUNTAIN-TOP STABLE LAYER REMAINING OVER THE SLOPES EAST OF THE CONTINENTAL DIVIDE WHICH WILL HELP PRODUCE THE AMPLIFIED MOUNTAIN WAVE WHICH WILL DRIVE THE ANTICIPATED CHINOOK HIGH WIND EVENT THROUGH THE NEXT 24 HOURS. CROSS SECTIONS AND PLAN VIEW WIND FIELDS INDICATE THAT THE STRONGEST WINDS SHOULD REMAIN IN THE FOOTHILLS. SINCE THE HIGH WIND WARNING IS ALREADY OUT FOR THE ADJACENT PLAINS...WILL LET IT CONTINUE...EVEN THOUGH CONFIDENCE IS LOW THAT STRONG WINDS WILL MAKE IT AS FAR EAST AS I-25. WINDS MAY EXTEND FURTHER EASTWARD TOMORROW AFTERNOON AS WARM TEMPERATURES ALLOW FOR GOOD MIXING OF THE BOUNDARY LAYER AND TRANSPORT OF THE JET STREAM ENERGY OVER A LARGER AREA. THE WARM TEMPERATURES ACROSS THE PLAINS WILL BE THE OTHER BIG STORY TOMORROW. GFS MOS GUIDANCE SEEMS TO BE OVERDOING THE WARMING...BUT THE NAM MOS GUIDANCE IS NOT WARM ENOUGH. WILL GO WITH AN AVERAGE OF THE TWO...EXCEPT FOR THE EASTERN ADAMS AND WASHINGTON COUNTY AREAS WHERE A SIGNIFICANT SNOWFIELD REMAINS IN PLACE. LONG TERM...NORTHWESTERLY FLOW ALOFT WILL INCREASE WEDNESDAY NIGHT WITH A 110-130 KNOT JET MAXIMUM TO MOVE SOUTHWARD CROSS THE CWA THURSDAY MORNING. STRONG NORTHWESTERLY FLOW ALOFT WILL CONTINUE OVER THE CWA THROUGH THURSDAY EVENING...THEN A 100-120 KNOT JET MAXIMUM WILL MOVE EASTWARD ACROSS THE FORECAST AREA INTO FRIDAY AFTERNOON. THE REST OF FRIDAY AND FRIDAY NIGHT...THE FLOW ALOFT WILL DECREASE AND BECOME ZONAL BY 12Z SATURDAY MORNING WITH AN UPPER RIDGE MOVING IN. WEAK UPWARD SYNOPTIC SCALE ENERGY IS PROGGED OVER THE EASTERN HALF OF THE CWA WEDNESDAY EVENING...THEN DOWNWARD VERTICAL VELOCITY IS PROGGED THROUGH FRIDAY. THE BOUNDARY LAYER WIND PROGGS HAVE WESTERLY DOWNSLOPING WEDNESDAY EVENING. AFTER MIDNIGHT...STRONGER NORTHWESTERLIES KICK IN AND CONTINUE THROUGH THURSDAY NIGHT. THE LOW LEVEL GRADIENT RELAXES FRIDAY AND FRIDAY NIGHT...WITH NORMAL DIURNAL WIND PATTERNS EXPECTED. FOR MOISTURE... IT INCREASES WEDNESDAY NIGHT OVER ALL THE FORECAST AREA...ESPECIALLY IN THE MOUNTAINS. EARLY THURSDAY MORNING...THE EASTERN PLAINS MOISTEN UP PRETTY GOOD. THE MOUNTAINS HAVE PRETTY DEEP MOISTURE IN PLACE THURSDAY AND THURSDAY EVENING...THEN IT DECREASES. THERE IS SOME MID AND UPPER LEVEL MOISTURE OVER THE PLAINS THURSDAY AND THURSDAY NIGHT. FRIDAY IS PRETTY DRY...FRIDAY NIGHT IS VERY DRY. THE QPF FIELDS HAVE LIMITED MEASURABLE SNOWFALL OVER THE MOUNTAINS...WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THERE IS A TAD OF PRECIPITATION OVER THE PLAINS FROM 06Z TO 18Z THURSDAY...BUT IT IS VERY LIMITED. THERE IS NOTHING ON FRIDAY OR FRIDAY NIGHT. FOR POPS IN THE MOUNTAINS...WILL GO WITH 60-80% WEDNESDAY NIGHT THROUGH THURSDAY EVENING. MOISTURE AND OROGRAPHICS ARE GOOD...AND THERE IS SOME COLD AIR ADVECTION AS WELL. WILL DECREASE ALPINE POPS AFTER MIDNIGHT THURSDAY NIGHT...WITH NOTHING FRIDAY AND FRIDAY NIGHT. FOR THE PLAINS...WILL HAVE POPS IN THE FROM WEDNESDAY NIGHT MIDNIGHT THROUGH THURSDAY. THE BEST POPS WILL BE OVER THE EASTERN HALF WITH A BETTER POTENTIAL FOR UPSLOPE AND BETTER MOISTURE. THERE IS PRETTY FIERCE DOWNSLOPING OVER THE WESTERN PLAINS. THE PLAINS WILL BE DRY THURSDAY NIGHT THROUGH FRIDAY NIGHT. CONCERNING THE WIND THREAT...WILL KEEP HIGHLIGHTS AS IS FOR WINDS GOING WEDNESDAY NIGHT. THE MOUNTAIN WAVE SET-UP STILL LOOKS SIGNIFICANT. FOR TEMPERATURES...THURSDAY HIGHS ARE 7-12 C COLDER THAN WEDNESDAY'S HIGHS. FRIDAY'S READINGS ARE UP 1-2 C FROM THURSDAY. FOR THE LATER DAYS...SATURDAY THROUGH TUESDAY...MEDIUM RANGE MODELS HAVE AN UPPER RIDGE OVER COLORADO SATURDAY. BY SUNDAY...UPPER TROUGHING MOVES. THE ECMWF IS QUICKER WITH THIS THAN THE GFS. THE UPPER TROUGH STICKS AROUND THROUGH TUESDAY FOR THE MOST PART. RUN TO RUN MODEL CONSISTENCY WITH THIS FEATURE HAS NOT BEEN GREAT. MANY OF THE SPECIFICS...MOISTURE...TEMPERATURE...TO NAME A FEW ARE ALL OVER THE PLACE. IT SHOULD COOL DOWN FROM SATURDAY AND THERE SHOULD BE A "SLIGHT CHANCE" OR A "CHANCE" OF SNOW OVER ALL THE FORECAST AREA FROM SUNDAY THROUGH TUESDAY. AVIATION...CEILINGS AND VSBYS WILL REMAIN UNLIMITED THROUGH THE NEXT 24 HOURS...BUT WINDS ARE GOING TO PRESENT THE GREATER OPERATIONAL CHALLENGE. STRONG NORTHWEST FLOW ALOFT IS GOING TO CONTINUE THROUGH WEDNESDAY NIGHT WITH PERIODS OF GUSTY WINDS ALONG THE FOOTHILLS. PERIODS OF GUSTY WEST WINDS WILL EXTEND OUT TO KDEN AT TIMES THROUGH THE NEXT 24 HOURS. GUSTS TO 35 KNOTS OR MORE WILL BE POSSIBLE DURING WINDY PERIODS...ESPECIALLY BETWEEN 15Z AND 00Z ON WEDNESDAY. && .BOU WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 5 AM MST THURSDAY FOR COZ033>036-038-039. WINTER WEATHER ADVISORY UNTIL 11 AM MST THURSDAY FOR COZ033. WINTER STORM WARNING UNTIL 11 AM MST THURSDAY FOR COZ031. && SHORT TERM...DANKERS LONG TERM....RPK UPDATE/AVIATION...MEIER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1109 AM MST TUE FEB 21 2012 COZ030>051-221300- 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- 1109 AM MST TUE FEB 21 2012 ...HIGH WIND WARNING FRONT RANGE MOUNTAINS...FOOTHILLS...AND NEARBY PLAINS LATE TONIGHT THROUGH WEDNESDAY NIGHT... ...WINTER WEATHER ADVISORY NORTHERN GORE AND PARK RANGE THROUGH WEDNESDAY MORNING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT GUSTY WEST WINDS WILL CONTINUE OVER THE HIGH MOUNTAIN PEAKS AND ALONG THE EASTERN SLOPES AND FOOTHILLS. AN UPPER LEVEL JET STREAM WILL MOVE OVER THE STATE TONIGHT...CAUSING PRESSURE GRADIENTS OVER NORTHEAST COLORADO TO STRENGTHEN. THIS WILL BRING EVEN STRONGER WINDS TO THE FOOTHILLS AND ADJACENT PLAINS. A HIGH WIND WARNING WILL BE IN EFFECT FOR POTENTIALLY DAMAGING WINDS TONIGHT. IN ADDITION TO STRONG WIND GUSTS...ROADWAYS NEAR OPEN FIELDS OF SNOW MAY BECOME SLICK BECAUSE OF BLOWING AND DRIFTING SNOW. MOISTURE MOVING INTO THE NORTHERN MOUNTAINS WILL CONTINUE PRODUCING SCATTERED SNOW SHOWERS IN THE COLORADO HIGH COUNTRY. ACCUMULATIONS IN THE NORTHERN GORE AND PARK RANGES MAY EXCEED 6 INCHES. OTHER MOUNTAIN RANGES WILL SEE LESSER AMOUNTS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY STRONG WINDS WILL OCCUR IN AND NEAR THE FRONT RANGE MOUNTAINS AND FOOTHILLS WEDNESDAY...WITH A GRADUAL RELAXING OF THE WINDS WEDNESDAY NIGHT. PEAK GUSTS APPROACHING 80 MPH CAN BE EXPECTED WEST OF I-25...WITH A FEW WIND PRONE AREAS IN THE FOOTHILLS SEEING WIND GUSTS NEAR 100 MPH. SNOW IS EXPECTED IN THE MOUNTAINS WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...WITH SEVERAL INCHES OF ADDITIONAL SNOW ACCUMULATION LIKELY. THE PLAINS WILL SEE A CHANCE OF SNOW WEDNESDAY NIGHT LATE INTO EARLY THURSDAY EVENING. THE BEST CHANCE WILL BE OVER THE EASTERN HALF OF THE PLAINS. DRY WEATHER IS EXPECTED OVER THE FORECAST AREA FRIDAY THROUGH SATURDAY. THE NEXT STORM WILL MOVE INTO THE FORECAST AREA SATURDAY NIGHT...BRINGING A CHANCE OF SNOW INTO EARLY NEXT WEEK TO MOST AREAS. TEMPERATURES WILL BE BELOW SEASONAL NORMALS MUCH OF THE TIME...WITH SATURDAY BEING WARMER. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. DANKERS/RJK
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
856 PM MST TUE FEB 21 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1233 PM NON-TSTM WND GST BLACK HAWK 39.80N 105.49W
02/21/2012 M69.00 MPH GILPIN CO MESONET
1256 PM NON-TSTM WND GST 2 NNE BLACK HAWK 39.83N 105.48W
02/21/2012 M73.00 MPH GILPIN CO MESONET
0148 PM NON-TSTM WND GST 12 S BOULDER 39.85N 105.25W
02/21/2012 M66.00 MPH JEFFERSON CO MESONET
AT THE INTERSECTION OF HIGHWAYS 93 AND 72 IN NORTH JEFCO.
0152 PM NON-TSTM WND GST 42 NW FORT COLLINS 40.98N 105.64W
02/21/2012 M73.00 MPH LARIMER CO TRAINED SPOTTER
0318 PM NON-TSTM WND GST 1 NW GOLDEN 39.75N 105.23W
02/21/2012 M73.00 MPH JEFFERSON CO MESONET
0321 PM NON-TSTM WND GST 7 SW BOULDER 39.96N 105.34W
02/21/2012 M81.00 MPH BOULDER CO MESONET
NEAR WONDERVU
0406 PM NON-TSTM WND GST 5 NW BOULDER 40.08N 105.32W
02/21/2012 M82.00 MPH BOULDER CO MESONET
0427 PM NON-TSTM WND GST 5 NW BOULDER 40.08N 105.32W
02/21/2012 M71.00 MPH BOULDER CO MESONET
0550 PM NON-TSTM WND GST VIRGINIA DALE 40.95N 105.35W
02/21/2012 M68.00 MPH LARIMER CO MESONET
0648 PM NON-TSTM WND GST 4 NE NEDERLAND 40.00N 105.45W
02/21/2012 M63.00 MPH BOULDER CO MESONET
0655 PM NON-TSTM WND GST 1 SW BROOMFIELD 39.93N 105.08W
02/21/2012 M68.00 MPH BROOMFIELD CO ASOS
ROCKY MOUNTAIN METROPOLITAN AIRPORT
0655 PM NON-TSTM WND GST ROCKY FLATS 39.89N 105.20W
02/21/2012 M66.00 MPH JEFFERSON CO MESONET
&&
MRBThe national radar mosaic for the moment the first event began.
8 high wind. 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: 365960, 365961, 365962, 365963, 365967, 365965, 365966, 365964.