A winter storm brought heavy snow to the North Central Mountains of Colorado. The heaviest snowfall occurred in the mountains north of Interstate 70.
Every event with a place to put it; 3 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 winter storm brought heavy snow to the North Central Mountains of Colorado. The heaviest snowfall occurred in the mountains north of Interstate 70. Storm totals included: 31.5 inches, 9 miles east-northeast of Steamboat Springs; 21 inches at Mt Zirkel SNOTEL; 18 inches at Arapahoe Ridge SNOTEL; 16.5 inches near Rabbit Ears Pass; 15 inches at Bear Lake State Park; 13.5 inches at Cameron Pass; 4 miles south of Longs Peak; 8 miles south-southeast of Rand and 5 miles east-northeast of Mt Audubon; 12 inches at Lake Irene; 10.5 inches, 9 miles east of Glendevy; and 10 inches at Loveland Ski Area.
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 21, 8:35 PM MST, 25 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER/BOULDER CO 835 PM MST MON DEC 21 2015 .UPDATE... ISSUED AT 835 PM MST MON DEC 21 2015 WINDS HAVE PICKED UP OVER THE HIGHER MOUNTAINS WITH A GUST TO 71 MPH AT BERTHOUD PASS AT 12490 FEET MSL. EXPECT STRONG WINDS TO CONTINUE OVER THE HIGHER LOCATIONS THROUGH THEN NIGHT. AIRMASS AT AND JUST ABOVE RIDGE TOP NOT THAT STABLE WITH LAPSE RATES 5-7C/KM. IT WILL BE DIFFICULT FOR THE STRONG WINDS TO DESCEND DOWN THE FOOTHILLS. WILL LEAVE THE HIGH WIND WARNING IN PLACE...THOUGH THE MAIN THREAT FOR STRONG WINDS LOOKS TO BE THE HIGHER LOCATIONS IN THE FOOTHILLS. RADAR SHOWING WIDESPREAD SNOW OVER WESTERN COLORADO AT THIS TIME. THE SNOW WILL SPREAD EAST OVER THE NORTH CENTRAL MOUNTAINS THROUGH THE NIGHT. BUMPED UP POPS A LITTLE MORE FOR THIS AS SNOW LOOKS MORE CERTAIN. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 355 PM MST MON DEC 21 2015 A WINTER STORM WARNING AND HIGH WIND WARNING GO INTO EFFECT OVERNIGHT. A STRONG AND ABNORMALLY MOIST FLOW ALOFT WILL STRADDLE NORTH CENTRAL COLORADO FOR THE NEXT 24 TO 48 HOURS. IN ADDITION A COUPLE MID-LEVEL DISTURBANCES EMBEDDED IN THIS 100-150KT FLOW WILL PASS OVER THE REGION...THE FIRST OF THESE AROUND 06Z TONIGHT. STRONG OROGRAPHICS AND COLD AIR ADVECTION ON THE BACK SIDE OF THIS SHORTWAVE SHOULD SET OFF THE STRONG WINDS AND MODERATE TO HEAVY SNOWFALL EXPECTED IN THE HIGH COUNTRY. ALTHOUGH COULD SEE SNOWFALL BEGINNING THIS EVENING PARTICULARLY IN THE PARK AND GORE RANGES. IN ADDITION...STRONG SUBSIDENCE IN THE WAKE OF THE SHORTWAVE AND THE FORMATION OF A MTN WAVE ARE EXPECTED TO GENERATE SEVERAL HRS OF VERY STG AND GUSTY WEST WINDS IN THE FRONT RANGE FOOTHILLS. CROSS SECTIONS INDICATE STRONG CROSS MTN FLOW FROM 04Z TO 09Z TONIGHT..WITH THE STRONGEST WINDS ROUGHLY ABOVE 8500 FEET. COULD SEE GUSTS PEAKING AROUND 75 MPH...WITH SUSTAINED WINDS IN THE 35-50 MPH IN MOST AREAS. COULD SEE SIMILAR WINDS ABOVE TIMBERLINE AND ON HIGHER EAST SLOPE OF THE FRONT RANGE. HOWEVER DECIDED TO HIT THIS AREA WITH A WINTER STORM WARNING AND CONCENTRATE OF THE POTENTIAL FOR HEAVY SNOW AND NEAR BLIZZARD CONDITIONS LATER TONIGHT AND TUESDAY. LOWER FOOTHILLS COULD ALSO SEE STG AND GUSTY WEST WINDS DEVELOPING AFTER MIDNIGHT WITH FALLING PRESSURES ON THE PLAINS. ALTHOUGH WIND GUSTS IN THIS AREA ARE EXPECTED TO REMAIN BELOW HIGH WIND CRITERIA. ON THE PLAINS...ONLY LIGHT DRAINAGE WINDS UNDER CLEAR TO PARTLY CLOUDY SKIES. ON TUESDAY...SNOWFALL IN THE HIGH COUNTRY WILL CONTINUE...POSSIBLY BECOMING HEAVIER DURING THE MORNING HOURS WITH INCREASING LIFT...OROGRAPHIC FORCING AND DEEPER MOISTURE. COULD SEE 1-2 INCH PER HOUR SNOWFALL RATES IN THE PARK RANGE AND UP ALONG THE CONTINENTAL DIVIDE AROUND THE INDIAN PEAKS DURING THE MORNING AND EARLY AFTERNOON. THEN A MODEST DECREASE IN SNOWFALL INTENSITY AND WIND SPEEDS DURING THE AFTERNOON WITH THINNING OF THE MOISTURE CHANNEL. SNOW TOTALS BY LATE AFTERNOON ANYWHERE FROM 8-15 INCHES IN MTN ZONE 31...AND 7-14 INCHES IN MTN ZONES 33/34. SEE LITTLE IF ANY SNOW ACCUMULATION IN THE FOOTHILLS ZONES BECAUSE OF THE STRONG DOWNSLOPING WINDS AND DRYING IN THIS AREA. ON THE PLAINS...NO PRECIP TO SPEAK OF ON TUESDAY. LIGHT DRAINAGE WINDS EARLY APPEAR TO SHIFT TO A SELY COMPONENT BY AFTERNOON WITH FALLING PRESSURE ALONG THE FOOTHILLS. SHOULD SEE LITTLE CHANGE IN TEMPERATURE TONIGHT AND TUESDAY FROM THOSE OBSERVED LAST NIGHT AND TODAY...GENERALLY NEAR TO SLIGHTLY ABOVE AVERAGE. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 355 PM MST MON DEC 21 2015 UNSETTLED PATTERN BRINGS CONTINUED LIGHT SNOW TO THE MOUNTAINS THROUGH THE EXTENDED PERIOD. FOR TUESDAY NIGHT INTO WEDNESDAY A SHORTWAVE WILL PASS IN NW FLOW BRINGING INCREASED MOISTURE TO THE NW MOUNTAINS AND ONGOING SNOW INTO WEDNESDAY. DECENT LIFT WILL ALLOW FOR ANOTHER 1-3 INCHES OVERNIGHT INTO WEDNESDAY FOR THE PARK AND GORE RANGES. FOR THE PLAINS THE SURFACE LOW WILL MOVE SOUTH ALLOWING FOR A SLIGHT CHANCE OF SNOW FOR THE NORTHERN PLAINS BY WEDNESDAY MORNING. NO ACCUMULATIONS ARE EXPECTED WITH THIS SYSTEM. TEMPERATURES ON WEDNESDAY WILL BE COOLER WITH THE PASSAGE OF THE TROUGH BRINGING HIGHS JUST ABOVE FREEZING AND OVERNIGHT TEMPERATURES INTO THE TEENS. MOISTURE WILL DECREASE WEDNESDAY INTO THURSDAY AS THERE IS A TRANSITIONAL PERIOD BETWEEN THE TWO DISTURBANCES. ZONAL FLOW TURNS SW AS THE TROUGH OVER THE WEST COAST DIGS INTO THE GREAT BASIN THURSDAY. THERE IS SOME MID LEVEL RIDGING THAT WILL HELP TO DRY OUT THE REGION LEAVING CLOUDS AND A SLIGHT CHANCE OF FLURRIES IN THE MOUNTAINS AND PARTLY CLOUDY SKIES OVER THE PLAINS. TEMPERATURES WILL REMAIN COOL HOWEVER WITH HIGHS IN THE 30S. SW FLOW DOMINATES THE UPPER LEVEL PICTURE FOR FRIDAY AS THE TROUGH CONTINUES TO DIG SE. MOISTURE AHEAD OF THE TROUGH INCREASES FRIDAY AS A COLD FRONT MOVES THROUGH FRIDAY MORNING INTO SATURDAY. THIS FEATURE WILL BRING SNOW TO THE MOUNTAINS AND A SLIGHT CHANCE OF SNOW TO THE PLAINS BY FRIDAY EVENING. BY THE WEEKEND THE UPPER LOW WILL CONTINUE TO DIG SOUTH INTO NEW MEXICO WITH STRONG NORTHERLY FLOW AT THE SURFACE. THE MODELS START TO DIVERGE SATURDAY INTO SUNDAY WITH THE TRACK OF THE LOW. THE GFS HAS IT MOVING BACK TO THE NW SUNDAY INTO MONDAY WITH THE EC MOVING IT MORE EASTWARD. ONE BRINGS SNOW TO THE REGION AND ONE DOES NOT. WILL MAINTAIN LIGHT POPS FOR THE SOUTHERN COUNTIES SATURDAY EVENING AND SUNDAY. TEMPERATURES WILL BE MUCH COOLER WITH HIGHS IN THE TEENS AND LOW 20S AND OVERNIGHT LOWS IN THE SINGLE DIGITS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 835 PM MST MON DEC 21 2015 VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS. SOUTHERLY DRAINAGE WINDS WILL CONTINUE INTO TUESDAY MORNING. MAY BE A FEW GUSTS TO 25 KNOTS. WINDS WILL SHIFT NORTHEAST TO EAST TUESDAY AFTERNOON AS A WEAK SYSTEM MOVES ACROSS THE AREA. CLOUDS WILL INCREASE AND LOWER...BUT CEILINGS ARE EXPECTED TO STAY ABOVE 6000 FEET. && .BOU WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 6 AM MST TUESDAY FOR COZ035-036. WINTER STORM WARNING UNTIL 6 AM MST WEDNESDAY FOR COZ033-034. WINTER STORM WARNING UNTIL 6 AM MST WEDNESDAY FOR COZ031. && UPDATE...MEIER SHORT TERM...BAKER LONG TERM...BOWEN AVIATION...MEIER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER/BOULDER CO 1138 AM MST MON DEC 21 2015 COZ030>051-221845- 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- 1138 AM MST MON DEC 21 2015 ...HEAVY SNOWFALL AND STRONG WINDS ON THE WAY FOR PORTIONS OF THE NORTHERN COLORADO HIGH COUNTRY TONIGHT AND TUESDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT LIGHT TO MODERATE SNOWFALL WILL SPREAD EAST OVER THE MOUNTAIN RANGES OF NORTH CENTRAL COLORADO LATER THIS AFTERNOON AS PACIFIC MOISTURE STREAMS IN FROM THE WEST. THE PARK AND GORE RANGES IN WESTERN GRAND AND JACKSON COUNTIES COULD SEE UP TO 2 INCHES OF SNOW BY LATE THIS AFTERNOON AND ANOTHER 4 TO 8 INCHES OF SNOW BY TUESDAY MORNING. MOUNTAIN RANGES TO THE SOUTH AND EAST OF THERE SUCH AS THE RABBIT EARS...MEDICINE BOW...TEN MILE AND MOSQUITO RANGES... AS WELL AS THE RIDGETOPS AND WEST FACING SLOPES OF THE FRONT RANGE COULD SEE ANYWHERE FROM 3 TO 6 INCHES OF SNOW DURING THIS SAME TIME PERIOD. THIS INCLUDES THE LOWER VALLEY AREA IN SUMMIT COUNTY. IN ADDITION...SUSTAINED WESTERLY WINDS OF 35 TO 45 MPH AND GUSTS TO AROUND 70 MPH COULD PRODUCE NEAR WHITEOUT OUT CONDITIONS AND CONSIDERABLE DRIFTING ABOVE TIMBERLINE AND ON THE HIGH MOUNTAIN PASSES OVERNIGHT. TIRE CHAINS AND ADEQUATE SNOW TIRE MAY BE REQUIRED FOR HIGH COUNTRY TRAVEL FOR A TIME OVERNIGHT. IN ADDITION...VERY STRONG WEST WINDS ALOFT ARE EXPECTED TO SPREAD DOWN THE EAST FACE OF THE FRONT RANGE STARTING LATE THIS AFTERNOON AND CONTINUE OVERNIGHT. THE STRONGEST WIND GUSTS IN THE 45 TO 70 MPH RANGE ARE EXPECTED TO OCCUR DURING THE EVENING HOURS AND MAINLY IN AREAS ABOVE 8000 FEET. AREAS BELOW 8000 COULD STILL SEE GUSTS IN THE 35 TO 60 MPH RANGE. THESE STRONG AND GUSTY WINDS ARE LIKELY TO PRODUCE CONSIDERABLE BLOWING SNOW IN THESE AREAS AS WELL. DRY CONDITIONS WITH MUCH LIGHTER WINDS ARE TO BE EXPECTED ON THE PLAINS. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY SNOWFALL AND GUSTY WINDS WILL CONTINUE OVER THE HIGH COUNTRY TUESDAY. SNOWFALL RATES WILL BE BETWEEN ONE HALF AND ONE INCH PER HOUR. GUSTY WINDS BETWEEN 50 AND 70 MPH IN THE MOUNTAINS WILL CAUSE REDUCED VISIBILITY IN BLOWING SNOW...CREATING HAZARDOUS TRAVEL CONDITIONS ON ICY OR SNOWPACKED ROADS. WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE FOR THE HIGHER FOOTHILLS TONIGHT INTO TOMORROW MORNING. MOUNTAIN SNOW WILL DECREASE AFTER MIDNIGHT TUESDAY NIGHT...BUT WILL REMAIN AT LIGHTER AMOUNTS FOR THE REST OF THE WEEK AS MOISTURE RIDES IN ON WESTERLY FLOW. COLDER THAN AVERAGE TEMPERATURES ARE EXPECTED AS A LARGE TROUGH COVERS THE WESTERN AND CENTRAL STATES. THE PLAINS MAY SEE LIGHT AREAS OF SNOW WEDNESDAY WITH A SLIGHTLY BETTER CHANCE FOR CHRISTMAS EVENING. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. BAKER/BOWEN
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
548 PM MST MON DEC 21 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0400 PM NON-TSTM WND GST 8 NE FOUR CORNERS 40.94N 105.80W
12/21/2015 M83.00 MPH LARIMER CO TRAINED SPOTTER
&&The national radar mosaic for the moment the first event began.
2 winter storm, 1 winter weather. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2015Every state in 2015This day in weather historyWarnings in Colorado, December 2015
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: 607732, 607733, 607738.