A snowmobiler was injured when he triggered an avalanche near Jones Pass, in near whiteout conditions. Visibilities at the time ranged from 10 feet to 100 feet.
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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 snowmobiler was injured when he triggered an avalanche near Jones Pass, in near whiteout conditions. Visibilities at the time ranged from 10 feet to 100 feet. He was caught and buried in the slide that was approximately 100 feet long. While in the avalanche, he discharged his airbag which helped him to float to the surface. The snowmobiler was partially buried in approximately 6 to 18 inches of snow.
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 12, 3:46 AM MST, 7 hours 59 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 346 AM MST SUN DEC 12 2010 .SHORT TERM...NW FLOW ALOFT WILL REMAIN OVER THE AREA THRU TONIGHT. CROSS-SECTIONS SHOW FAVORABLE OROGRAPHIC FLOW IN THE MTNS TODAY WITH MOISTURE DEPTH RANGING AROUND 200 MB HOWEVER LAPSE RATES ARE RATHER STABLE. MODELS DO SHOW A DISTURBANCE MOVING ACROSS THE AREA BY MIDDAY WHICH COULD BRIEFLY ENHANCE SNOW SOMEWHAT FOR A FEW HOURS HOWEVER EXPECT AMOUNTS WILL BE FAIRLY LIGHT CONSIDERING POOR LAPSE RATES. ALSO WILL CONTINUE TO SEE GUSTY WINDS OVER THE HIGHER PASSES WITH AREAS OF BLOWING SNOW. AT LOWER ELEVATIONS EXPECT DRY CONDITIONS WITH TEMPS MODERATING THIS AFTN. 850-700 MB TEMPS RISE FROM 8-9 DEGREES C ALONG THE FRONT RANGE WHICH WILL ALLOW READINGS TO REACH THE LOWER TO MID 50S AROUND THE DENVER AREA WHILE THE PLAINS STAY IN THE 40S. WINDS WILL BE GUSTY IN THE FOOTHILLS THIS AFTN AND TONIGHT HOWEVER COMPONENT ALONG WINDS ARE ONLY FCST IN THE 25-30 KT RANGE SO SPEEDS SHOULD STAY BLO HIGHLIGHT CRITERIA. BY THIS EVENING MOISTURE SHOULD GRADUALLY DECREASE IN THE MTNS SO SNOW SHOWER ACTIVITY SHOULD END BY AROUND MIDNIGHT. .LONG TERM...MODELS SHOW UPPER RIDGING OVER COLORADO MONDAY THROUGH TUESDAY...WITH PRETTY STRONG WEST-NORTHWESTERLY FLOW ALOFT. BY TUESDAY NIGHT...A STRONG ZONAL JET MAXIMUM IS PROGGED TO MOVE INTO THE FORECAST AREA. JET LEVEL WIND SPEEDS ARE AROUND 145 KNOTS BY 12Z WEDNESDAY MORNING. THE SYNOPTIC SCALE ENERGY IS BENIGN MONDAY THROUGH TUESDAY...WITH WEAK UPWARD VERTICAL VELOCITY PROGGED TUESDAY NIGHT. THE BOUNDARY LAYER FLOW WILL BE DOMINATED BY LOW LEVEL TROUGHING EAST OF THE MOUNTAINS...MAINLY DOWNSLOPING. FOR MOISTURE ...MONDAY IS DRY...THERE IS SOME MID AND UPPER LEVEL MOISTURE MOVING IN MONDAY OVERNIGHT WELL INTO TUESDAY. BY TUESDAY EVENING...DEEPER MOISTURE MOVES INTO THE MOUNTAINS...WITH JUST SOME IN THE MID AND UPPER LEVELS OVER THE PLAINS. QPF FIELDS HAVE NOTHING OVER THE FORECAST AREA MONDAY...MONDAY NIGHT...AND TUESDAY. BOTH MODELS HAVE LIMITED MEASURABLE SNOWFALL IN THE MOUNTAINS TUESDAY NIGHT. FOR POPS ...NOTHING OVER THE PLAINS THROUGH TUESDAY NIGHT. IN THE MOUNTAINS ...NONE MONDAY THROUGH TUESDAY. FOR TUESDAY NIGHT...THERE IS DECENT MOISTURE...OROGRAPHICS ARE NOT GREAT...THERE IS LITTLE TEMPERATURE ADVECTION...AND THE LAPSE RATES ARE POOR. WILL STILL GO "CHANCE"S BUT NOTHING GREAT. SOME OF THE MODELS SHOW A MOUNTAIN WAVE TUESDAY NIGHT...BUT IT'S NOT GREAT. WITH A STRONG NEAR ZONAL JET MAXIMUM PROGGED TO MOVE IN LATER TUESDAY NIGHT...WINDS COULD EASILY BECOME AN ISSUE. FOR TEMPERATURES...MONDAY'S HIGHS ARE 4-6 C WARMER THAN SUNDAY'S HIGHS. TUESDAY'S HIGHS WARM UP ANOTHER 1-3 C ABOVE MONDAY'S. FOR THE LATER DAYS...WEDNESDAY THROUGH SATURDAY...MODELS KEEP STRONG ZONAL FLOW ALOFT FOR THE FORECAST AREA WEDNESDAY INTO THURSDAY. WEAKER ZONAL FLOW IS PROGGED FOR THE REST OF THURSDAY INTO FRIDAY. A WEAK UPPER TROUGH IS PROGGED TO MOVE ACROSS FRIDAY ...WITH A RETURN TO STRONG FLOW ALOFT. THIS TIME IT IS MORE NORTHWESTERLY IN DIRECTION. MOISTURE IS FAIR THROUGH THE DAYS...AND MOSTLY CONFINED TO THE MOUNTAINS. THERE IS SOME WEAK LOW LEVEL UPSLOPE PROGGED OVER THE PLAINS WEDNESDAY AND AGAIN THURSDAY NIGHT INTO FRIDAY. WILL KEEP SOME POPS IN THE MOUNTAINS MUCH OF THE TIME...BUT NOTHING OVER 30%S AT THIS TIME. TEMPERATURES GET CLOSER TO SEASONAL NORMALS THROUGH MUCH OF THE TIME. && .AVIATION...VFR THRU TONIGHT AS ANY CLOUD DEVELOPMENT TODAY SHOULD BE AOA 10000 FT BASED ON LATEST CROSS-SECTIONS. DRAINAGE WINDS EARLY THIS MORNING MAY BECOME MORE WNW BY AFTN AND THEN BACK TO DRAINAGE SHORTLY AFTER SUNSET. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. RPK/RJK
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1106 AM MST SUN DEC 12 2010 COZ030>051-131300- 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- 1106 AM MST SUN DEC 12 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SNOW SHOWERS WILL CONTINUE IN THE MOUNTAINS TODAY WITH ACCUMULATIONS OF 1 TO 4 INCHES. GUSTY WEST TO NORTHWEST WINDS WILL PRODUCE AREAS OF BLOWING SNOW OVER THE HIGHER PASSES. WEST TO NORTHWEST WINDS 15 TO 30 MPH WILL OCCUR WITH GUSTS TO 50 MPH ABOVE TIMBERLINE. AT LOWER ELEVATIONS IT WILL BE DRY WITH WARMER TEMPERATURES. THE SNOW WILL GRADUALLY END IN THE MOUNTAINS THIS EVENING. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY DRY AND WARM WEATHER IS EXPECTED ACROSS THE FORECAST AREA MONDAY AND TUESDAY...WITH WINDY PERIODS...ESPECIALLY IN THE HIGH COUNTRY. THE NEXT STORM SYSTEM WILL HIT THE MOUNTAINS BEGINNING TUESDAY NIGHT AND WEDNESDAY WITH A CHANCE FOR LIGHT SNOW CONTINUING INTO THURSDAY. FOR THE PLAINS...THROUGH WILL BE A CHANCE FOR SOME LIGHT RAIN OR SNOW WEDNESDAY WITH THE CHANCE FOR LIGHT SNOW CONTINUING INTO THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. COOPER/MEIER
The national radar mosaic for the moment the first event began.
1 avalanche. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2010Every state in 2010This day in weather historyWarnings in Colorado, December 2010
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: 268376.