Cold and moist air across western Colorado and eastern Utah combined with an upper level Pacific shortwave trough to produce widespread snowfall. The heaviest snow favored the mountains of southwest Colorado and southeast Utah.
Every event with a place to put it; 20 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 GJT wrote it up.
Cold and moist air across western Colorado and eastern Utah combined with an upper level Pacific shortwave trough to produce widespread snowfall. The heaviest snow favored the mountains of southwest Colorado and southeast Utah.
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 Grand Junction, CO wrote its last area forecast discussion before the first event at Dec 29, 4:43 AM MST, 2 hours 17 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 443 AM MST TUE DEC 29 2009 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT... WEATHER REGIME CHANGE IS UNDERWAY THIS MORNING. TODAY AND TONIGHT: A SPLIT TROUGH OF PACIFIC LOW PRESSURE WORKS THROUGH THE REGION. DYNAMICAL LIFT IS UNIMPRESSIVE AND OROGRAPHIC LIFT SHIFTS...AS SW FLOW ALOFT QUICKLY VEERS TO WEST TODAY. WEAK COLD ADVECTION BEGINS THIS MORNING ENDING ISENTROPIC UPGLIDE. MOISTURE AMOUNTS WITH THIS TROUGH ARE SIGNIFICANT THOUGH... WITH PRECIPITABLE WATER RISING TO 0.3+ INCHES. THIS MOISTURE PROGGED TO WORK ITS WAY TO THE SURFACE FOR MOST AREAS SOUTH OF I-70 TODAY. SINGLE DIGIT VALLEY DEWPOINTS WILL RISE INTO THE 20S. THIS TOP DOWN MOISTURE WILL HELP WEAKEN AND ERODE VALLEY INVERSIONS LIMITING OVERRUNNING SNOWFALL. SNOW IN THE LOWER ELEVATIONS NEAR THE FOUR- CORNERS COULD CHANGE OVER TO RAIN THIS AFTERNOON IF THE VALLEY INVERSIONS ARE FULLY BROKEN. OVERALL HAVE RAISED POPS BUT EXPECT ONLY LIGHT PRECIPITATION AMOUNTS. WEDNESDAY-WEDNESDAY NIGHT: A STRONGER AND MORE ORGANIZED TROUGH OF LOW PRESSURE DIGS IN FROM THE NW. 10KT JET STREAK WORKS INTO SE UTAH LATE WEDNESDAY AFTERNOON-EARLY EVENING VEERING THE FLOW TO NW. THE SLIGHTLY DEEPER AND SLOWER NAM IS FAVORED. -32C COLD CORE PASSES ACROSS THE NORTH EARLY THURSDAY WITH MTN TOP TEMPERATURES AT -12 TO -14C. SNOWFALL WILL INCREASE ON WEDNESDAY AFTERNOON-NIGHT WITH SIGNIFICANT ACCUMULATIONS EXPECTED IN THE NORTHERN COLORADO MTNS. ADVISORY CRITERIA LOOKS POSSIBLE FOR THE PARK/GORE/FLATTOPS/ELK MTN RANGES BUT THERE IS SOME UNCERTAINTY ON LOCATION OF BEST DYNAMICAL LIFT AND AVAILABLE MOISTURE. SO WILL LET THE DAY SHIFT LOOK AT THIS IN DETAIL. HAVE RAISED POPS AND SNOW AMOUNTS. .LONG TERM...THURSDAY THROUGH MONDAY... NORTHWEST FLOW ALOFT WILL CONTINUE TO SQUEEZE OUT ANY REMAINING MOISTURE OVER THE NORTHERN ZONES THURSDAY MORNING AS THIS STORM DEPARTS THE REGION. COVERAGE OF SNOW SHOWERS WILL BE DECREASING DURING THE AFTERNOON HOURS...WITH ACTIVITY BECOMING MORE ISOLATED IN NATURE BY THURSDAY NIGHT AS FLAT SHRTWV RIDGE BUILDS IN. PATTERN REMAINS PROGRESSIVE SO REMNANTS OF THIS RIDGE WILL BE EXITING EAST BY FRIDAY AS ANOTHER SURGE OF PACIFIC MOISTURE AND SHRTWV ENERGY MOVES IN FROM THE WEST. FAVORABLE NORTHWEST FLOW BECOMES RE- ESTABLISHED BY FRIDAY AFTERNOON...WITH SNOW SHOWERS DEVELOPING ONCE AGAIN OVER THE NORTHERN AND CENTRAL MOUNTAINS. WEAK JET STREAK PASSES JUST TO THE NORTH OF THE FORECAST AREA ON SATURDAY...CLIPPING THE NORTHERN ZONES. EXPECT TO SEE A BRIEF UPTICK IN QPF POTENTIAL DURING THIS PERIOD WITH ANOTHER WAVE POISED TO DROP SOUTH LATE SATURDAY NIGHT AND SUNDAY. THIS WILL EVENTUALLY BRING MORE OF THE COLD WEATHER TO THE REGION BY EARLY NEXT WEEK. WITH FAIRLY ACTIVE PATTERN...EXPECT CONDS TO REMAIN FAIRLY WELL MIXED...SO MOST VALLEYS WILL BE SEEING TEMPS RUNNING NEAR SEASONAL NORMS THROUGH AT LEAST SUNDAY. && .AVIATION... SOUTH OF A KCNY-KGJT-KMTJ-KGUC LINE...LIGHT SNOW SHOWERS WILL DEVELOP THIS MORNING PRODUCING MVFR CIGS AND VSBY...MAINLY OVER THE SAN JUAN...LA SAL AND ABAJO MOUNTAINS. SNOW WILL INCREASE AND SPREAD NORTHWARD THIS AFTERNOON FOR MORE WIDESPREAD MVFR CONDITIONS ALONG WITH LOCALIZED IFR CIGS AND VSBYS AT TIMES. THESE CONDITIONS WILL THEN PERSIST THROUGH WEDNESDAY. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. SHORT TERM...JOE LONG TERM....JDC AVIATION.....JDC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 545 AM MST TUE DEC 29 2009 COZ001>014-017>023-UTZ022>025-027>029-301245- ANIMAS RIVER BASIN-ARCHES/GRAND FLAT-CANYONLANDS/NATURAL BRIDGES- CENTRAL COLORADO RIVER BASIN- CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN- CENTRAL YAMPA RIVER BASIN-DEBEQUE TO SILT CORRIDOR- EASTERN UINTA BASIN-EASTERN UINTA MOUNTAINS- ELKHEAD AND PARK MOUNTAINS-FLAT TOPS- FOUR CORNERS/UPPER DOLORES RIVER- GORE AND ELK MOUNTAINS/CENTRAL MOUNTAINS-GRAND AND BATTLEMENT MESAS- GRAND VALLEY-LA SAL AND ABAJO MOUNTAINS-LOWER YAMPA RIVER BASIN- NORTHWEST SAN JUAN MOUNTAINS-PARADOX VALLEY/LOWER DOLORES RIVER- ROAN AND TAVAPUTS PLATEAUS-SAN JUAN RIVER BASIN-SOUTHEAST UTAH- SOUTHWEST SAN JUAN MOUNTAINS-TAVAPUTS PLATEAU- UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE-UPPER GUNNISON RIVER VALLEY- UPPER YAMPA RIVER BASIN-WEST ELK AND SAWATCH MOUNTAINS- 545 AM MST TUE DEC 29 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT SNOWFALL WILL SPREAD FROM SOUTH TO NORTH TODAY...REACHING THE NORTHERN MOUNTAINS BY TONIGHT. SNOW ACCUMULATIONS ARE EXPECTED TO BE LESS THAN 6 INCHES OVER THE MOUNTAINS THROUGH TONIGHT...WITH 1 TO 3 INCHES OVER THE VALLEYS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY MOUNTAIN SNOWFALL WILL INCREASE IN INTENSITY WEDNESDAY AFTERNOON THROUGH THURSDAY...FAVORING THE MOUNTAINS OF NORTHWEST COLORADO. SNOWFALL REMAINS POSSIBLE THROUGH THE WEEKEND...FAVORING THE NORTH. .SPOTTER INFORMATION STATEMENT SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT. BUT YOU ARE ENCOURAGED TO REPORT SIGNIFICANT SNOW OR STRONG WIND GUSTS TO THE NATIONAL WEATHER SERVICE IN GRAND JUNCTION. TGJT
The national radar mosaic for the moment the first event began.
18 winter weather, 2 winter storm. Local standard time, as filed.
Snowfall of 5 to 12 inches occurred mainly above the 7,000 foot level. Locally higher amounts included 15 inches over Columbine Pass.
Snowfall of 2 to 4 inches occurred with some locally higher amounts, including 7 inches at a location 6 miles southeast of Mack. The wet snowfall created slippery road conditions as the temperatures began to fall, causing a pickup to slide out of control on I-70 near the Clifton on-ramp.
Snowfall of 3 to 5 inches occurred across the area with locally higher amounts of up to 6 inches reported in the Norwood area.
Snowfall of 5 to 12 inches occurred with locally higher amounts, including 17 inches at the Mancos SNOTEL site. The snowfall created very slick road conditions, and caused a rollover accident just south of Tamarron along Highway 550. The snow also caused a few natural avalanches over Highway 550 that resulted in a few short road closures. Wind gusts up to 30 mph also produced localized blowing snow.
Snowfall of 2 to 4 inches occurred across the area with some locally higher amounts, including 9 inches in Hayden.
Snowfall of 5 to 11 inches occurred across the area.
Snowfall of 5 to 12 inches occurred. Locally higher amounts were reported, including 19 inches at Telluride Ski Area and 16 inches on Red Mountain Pass. The snowfall caused a few natural avalanches over Highway 550 that resulted in a few short road closures. Wind gusts up to 30 mph also produced localized blowing snow.
Snowfall of 4 to 12 inches occurred across the area with wind gusts up to 25 mph producing areas of blowing snow.
Snowfall of 2 to 5 inches occurred across the area and created very slick road conditions, resulting in a rollover vehicle accident just north of Highway 160 outside of the town of Durango.
Snowfall of 4 to 6 inches occurred across the area.
Snowfall of 10 to 17 inches occurred across the area with locally higher amounts reported, including 30 inches at the Tower SNOTEL site. Wind gusts up to 30 mph produced blowing and drifting snow.
Snowfall of 4 to 7 inches occurred across the area.
Snowfall of 3 to 6 inches occurred. Some locally higher amounts included 7 inches in the Mesa and Collbran areas.
Snowfall of 6 to 12 inches occurred across the area with locally higher amounts, including 19 inches at Powderhorn Ski Area. Wind gusts up to 30 mph produced blowing and drifting snow.
Snowfall of 5 to 12 inches occurred. Wind gusts up to 25 mph produced localized blowing snow.
Snowfall of 2 to 5 inches occurred with locally higher amounts, including 7 inches at a location 4 miles northeast of Crawford.
Snowfall of 2 to 4 inches occurred across about half of the area, with locally higher reports in some areas, including 7 inches at a location 11 miles south of Cimmaron.
Snowfall of 6 to 12 inches occurred across about half of the area. Locally higher amounts were reported, including 17 inches at Beaver Creek Ski Area and 14 inches at McCoy Park SNOTEL.
Snowfall of 2 to 6 inches occurred.
Snowfall of 5 to 9 inches occurred across the area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2009Every state in 2009This day in weather historyWarnings in Colorado, December 2009
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: 204876, 204871, 204877, 204867, 204869, 204728, 204866, 204859, 204878, 204880, 204725, 204879, 204872, 204730, 204862, 204874, 204875, 204738, 204873, 204870.