A winter storm produced areas of moderate to heavy snowfall in the North-Central Mountains. 5 inches at Cabin Creek, 10 inches at St.
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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 winter storm produced areas of moderate to heavy snowfall in the North-Central Mountains. Storm totals included: 11 inches at Roach SNOTEL, 10.5 inches at Cabin Creek, 10 inches at St. Mary's Glacier, 9 inches at Fremont Pass, Deadman Hill and Lake Irene; 7 inches at Summit Ranch and 6 inches at Columbine SNOTEL.
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 13, 3:27 AM MST, 2 hours 33 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 327 AM MST SUN DEC 13 2009 .SHORT TERM...WESTERLY FLOW ALOFT WILL CONTINUE OVER THE REGION THROUGH TONIGHT. SATELLITE SHOWING A GOOD AMOUNT OF MOISTURE EMBEDDED IN THE WESTERLY FLOW OVER NEVADA AND UTAH. THE MOISTURE ALONG WITH A SHORT WAVE IN THE FLOW ALOFT WILL MOVE OVER THE STATE TODAY. BEST LIFT ASSOCIATED WITH THE SHORT WAVE WILL OCCUR TODAY. MODELS SHOWING BETTER MOISTURE OVER THE MOUNTAINS THAN YESTERDAY. AS THE SHORT WAVE PASSES THROUGH...MOUNTAIN TOP WINDS WILL SWITCH FROM SOUTHWEST TO WEST PROVIDING BETTER OROGRAPHIC LIFT. HEAVIEST SNOW AMOUNTS WILL BE ALONG WEST FACING SLOPES. COLD AIR ADVECTION BEHIND THE WAVE WILL INCREASE THE LAPSE RATES...HELPING TO KEEP THE OROGRAPHIC SNOW FALLING. AS FAR AS SNOWFALL MOUNTAINS GO...EXPECT THEM TO BE REALLY VARIABLE BECAUSE OF THE OROGRAPHIC NATURE OF THE SNOW. WILL KEEP THE ADVISORY GOING FOR ZONE 31 WITH 7 TO 14 INCHES EXPECT BY MONDAY MORNING. AREAS WEST OF THE DIVIDE IN ZONES 33 AND 34 WILL GENERALLY SEE 3 TO 6 INCHES. A FEW FAVORED UPSLOPE AREAS MAY RECEIVE UP TO 10 INCHES THROUGH MONDAY MORNING. THE WESTERLY DOWNSLOPE FLOW WILL KEEP THE URBAN CORRIDOR AND EASTERN PLAINS DRY. HOWEVER...IT WILL BE A TRICKY TEMPERATURE FORECAST FOR THE URBAN CORRIDOR AND EASTERN PLAINS TODAY. A SURFACE LOW WILL FORM OVER NORTHEAST COLORADO TODAY. SOUTHWEST SURFACE WINDS ON THE BACK SIDE OF THE LOW WILL AGAIN BRING MILD TEMPERATURES TO THE FOOTHILLS AND AREAS SOUTH OF I-70 TODAY. SOME UNCERTAINTY TO EXACTLY HOW FAR THE SOUTHWEST WINDS WILL EXTEND OFF THE FOOTHILLS...AND THUS WHERE THE WARMER AIR WILL BE. WILL FOLLOW THE NAM12 WHICH SHOWS THE SOUTHWEST WINDS STAYING CONFINED TO THE FOOTHILLS OVER LARIMER AND BOULDER COUNTIES AND THEN SPREADS THEM EASTWARD THROUGH JEFFERSON COUNTY AND ACROSS ARAPAHOE AND ADAMS COUNTIES. ANOTHER PLAYER IN DETERMINING TEMPERATURES TODAY IS AN ARCTIC COLD FRONT PUSHING SOUTH THROUGH NEBRASKA AND TAILING NORTHWEST INTO NORTH CENTRAL WYOMING. MODELS SHOWING SOME OF THE COLD AIR WILL MAKE IT INTO THE NORTHEAST CORNER OF THE STATE. HAVE DROPPED HIGHS OVER THE NORTHEAST CORNER INTO THE LOWER 20S. .LONG TERM...MODELS AGREE IN MOVING AN OPEN WAVE TROUGH ACROSS THE ROCKY MTN REGION ON MONDAY. MUCH OF THE LARGE SCALE LIFT AND MOISTURE ASSOCIATED WITH THIS FEATURE APPARENTLY PASSES TO OUR NORTH OVER WYOMING AND MONTANA. HOWEVER WE SHOULD STILL SEE OUR SHARE OF SNOW SHOWERS IN OUR MTN AREAS PRINCIPALLY ALONG AND WEST OF THE CONTINENTAL DVD BEFORE OROGRAPHIC LIFT AND COLD ADVECTION DIMINISH DURING THE AFTERNOON HOURS. ALONG THE EAST SLOPE OF THE FRONT RANGE...WESTERLY/DOWNSLOPE FLOW SHOULD KEEP THINGS DRY AND RELATIVELY MILD ON MONDAY. WHILE FARTHER OUT ON THE PLAINS PARTICULARLY WITHIN THE PLATTE RVR BASIN...LIGHT EASTERLY BNDRY LYR FLOW WILL HELP TO OOZE IN A SHALLOW COLD AIR MASS WHICH COULD HOLD DAYTIME TEMPS TO THE UPPER 20S AND LOWER 30S IN THIS AREA. MAY EVEN SEE STRATUS AND PERHAPS SOME PATCHY FOG ALONG THE EASTERN BORDER OF THE CWFA LATE IN THE DAY...BUT DUE TO THE SHALLOW DEPTH OF THIS COLD AIR DO NOT ANTICIPATE ANY PCPN EXCEPT PERHAPS A FLURRY OR TWO. BY TUESDAY...UPR TROUGH MOVES EAST OF THE STATE ALLOWING A SOMEWHAT DRIER AND MORE STABLE NWLY FLOW ALOFT TO SET UP OVER THE AREA. MODEL SOUNDINGS AND CROSS SECTIONS STILL INDICATE ENOUGH MID-LEVEL MOISTURE AROUND TO ALLOW MTN WAVE CLOUDS TO PERIODICALLY FORM IN THE LEE OF THE FRONT RANGE DURING THE DAYLIGHT AND EVENING HOURS. MTN AREAS SHOULD ALSO SEE PERIODS OF CLOUDINESS WITH WARM ADVECTION... BUT SEE LITTLE IF ANY CHANCE FOR PRECIP FM THEM. MAY ALSO SEE GUSTY WLY WINDS POSSIBLY TO 50 MPH IN WIND PRONE AREAS OF THE FRONT RANGE TUE AFTERNOON AND EVENING. OUT ACROSS THE HIGH PLAINS...SHOULD SEE SHALLOW COLD AIR LAYER ERODING FROM WEST-TO-EAST THRU THE DAY...LAST TO EXIT LOWER PORTIONS OF THE SOUTH PLATTE RIVER VALLEY BY NIGHTFALL. ANY WARMING ON THE PLAINS TUESDAY EXPECTED TO BE MINIMAL DUE IN PART TO PREVAILING SNOW COVER...LOW SOLAR ANGLE AND WEAK SFC FLOW. YET STILL LOOKING FOR TEMPERATURES ON TUESDAY TO BE NEAR AVERAGE FOR THE DATE. IT/S WEDNESDAY WHEN TEMPERATURES ARE FCST TO CLIMB ABOVE DAILY NORMS...POSSIBLY AS MUCH AS 8-12F ABOVE AVERAGE. WILL LIKELY SEE WARMEST TEMP READINGS UP AGAINST THE FRONT RANGE FOOTHILLS...BUT THE GREAT POSITIVE TEMPERATURE CHANGE WILL OCCUR ACROSS THE NERN CORNER OF THE STATE WHERE MODELS NO LONGER SHOW ANY ARCTIC AIR HANGING AROUND. SFC LEE TROUGH COUPLED WITH MODERATE W/NWLY FLOW ALOFT SHOULD KEEP LEESIDE MTN SLOPES AND FTHLS BREEZY WHICH WILL FURTHER ENHANCE WARMING ON WEDNESDAY. PROBABLY THE LARGEST ADJUSTMENT TO THIS FORECAST PACKAGE COMES THURSDAY AND FRIDAY WHEN 00Z/06Z MODEL RUNS NOW SHOW A SHORTWAVE TROUGH RACING OUT OF THE PACIFIC NORTHWEST AND ACROSS COLORADO AND WYOMING. MODELS QUICKLY DEEPEN THIS SYSTEM AS THEY PUMP UP A SHORTWAVE RIDGE OVER THE GREAT BASIN AT THE SAME TIME. RIGHT NOW MODELS ONLY INDICATE SCATTERED LIGHT PCPN AND A TURN TO COOLER TEMPERATURES AS THIS SYSTEM PASSES. BUT SHOULD THIS TROUGH DIG MORE AND SLOW ITS FORWARD PROGRESS...WE COULD BE DEALING WITH A BIT MORE WEATHER. STAY TUNE. && .AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH MONDAY AFTERNOON. HIGHS CLOUDS WILL STREAM OVER THE STATE WITH CEILINGS REMAINING ABOVE 10000 FEET. A SURFACE LOW WILL FORM OVER NORTHEAST COLORADO RESULTING IN MAINLY SOUTH TO SOUTHWEST WINDS FOR KDEN. THERE IS A SLIGHT CHANCE WINDS COULD TURN MORE EAST TO NORTHEASTERLY DEPENDING ON THE POSITION OF THE SURFACE LOW. && .BOU WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY UNTIL 6 AM MST MONDAY FOR MOUNT ZIRKEL WILDERNESS AREA AND NORTHERN GORE RANGE...ZONE 31. MEIER/BAKER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 413 AM MST SUN DEC 13 2009 COZ030>051-131800- 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- 413 AM MST SUN DEC 13 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SNOW WILL FALL IN THE MOUNTAINS TODAY...MAINLY ALONG AND WEST OF THE CONTINENTAL DIVIDE. EXCEPT FOR WESTERN JACKSON AND GRAND COUNTIES WHERE 7 TO 14 INCHES WILL BE POSSIBLE...SNOWFALL AMOUNTS WILL GENERALLY BE IN THE 3 TO 7 INCH RANGE IN THE MOUNTAINS NEAR AND WEST OF THE CONTINENTAL DIVIDE. IN ADDITION TO THE SNOW...GUSTY WEST WINDS WILL CAUSE AREAS OF BLOWING AND DRIFTING SNOW. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY SCATTERED SNOW SHOWERS IN THE HIGH COUNTRY ON MONDAY WILL GIVE WAY TO WARMER AND DRIER CONDITIONS BY MIDWEEK. ON THE HIGH PLAINS OF NORTHEAST COLORADO...PRECIPITATION WILL REMAIN OUT OF THE PICTURE THROUGH MIDWEEK WITH DOWNSLOPE BREEZES SLOWLY RETURNING TEMPERATURES TO ABOVE NORMAL READINGS BY WEDNESDAY. FOR LATER IN THE WEEK...SNOW MAY RETURN TO THE MOUNTAINS AND HIGH VALLEYS ON THURSDAY WITH THE PASSAGE OF A FAST MOVING PACIFIC STORM SYSTEM. EVEN THE HIGH PLAINS MAY SEE A BIT OF SNOW THURSDAY NIGHT SHOULD THIS WEATHER SYSTEM INTENSITY AS IT MOVES OUT OF THE ROCKIES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. MEIER/BAKER
The national radar mosaic for the moment the first event began.
3 winter weather. Local standard time, as filed.
Storm totals included 6 inches at Columbine SNOTEL.
Storm totals included: 11 inches at Roach SNOTEL, and 9 inches at Fremont Pass, Deadman Hill and Lake Irene.
Storm totals included: 10.5 inches at Cabin Creek, 10 inches at St. Mary's Glacier and 7 inches at Summit Ranch.
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: 204288, 204289, 204290.