The first in a series of powerful winter storms brought a period of heavy snow to the north central mountains, Front Range Foothills and Urban Corridor. In the mountains and foothills, the heaviest snowfall occurred along and north of the Interstate 70 corridor.
Every event with a place to put it; 9 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.
The first in a series of powerful winter storms brought a period of heavy snow to the north central mountains, Front Range Foothills and Urban Corridor. In the mountains and foothills, the heaviest snowfall occurred along and north of the Interstate 70 corridor. Storm totals ranged from one to around three feet. Eastbound I-70 was closed at Vail and Silverthorne because of poor conditions and several spun-out vehicles. Across the Interstate 25 corridor, heavy snowfall fell over northern parts of metro Denver north to around Fort Collins. At Denver International Airport, 145 flights were canceled.
Some of the storm totals in the mountains and foothills included: 38.5 inches at Mt. Zirkel, 23 inches just northeast of Rabbit Ears Pass, 21.8 inches, 9 miles south-southeast of Spicer; 19.7 inches 5 miles northeast of Ward, 18 inches, 9 miles east of Glendive and 16 miles west-southwest of Walden; 17 inches, 3 miles south of Brainard Lake and Copeland Lake; 16 inches at Arapaho Basin and 5 miles east-northeast of Nederland and Niwot Ridge SNOTEL; 15.7 inches at Eldora, 15 inches at Estes Park, 14.5 inches at Berthoud Pass; 14 inches at Allenspark, 12.9 inches, 7 miles east-northeast of Virginia Dale, 12.7 inches in Breckenridge and 12 inches at Gross Reservoir.
Along the I-25 corridor, some of the storm totals included: 13.8 inches in Boulder, 12 inches at Marston Reservoir, 9.5 inches in Niwot, 9 inches at Flatiron Reservoir, 8.3 inches in Northglenn; 8 inches at Hygiene, 7 inches in Arvada, 5 miles west-northwest of Brighton, Frederick, Lafayette, Loveland and 5 miles northeast of Westminster; with 6.5 inches at Ralston Reservoir and Wheat Ridge.
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 Jan 3, 5:25 PM MST, 2 hours 35 minutes earlier.
Area Forecast Discussion National Weather Service Denver/Boulder CO 525 PM MST Tue Jan 3 2017 .SHORT TERM...(This evening through Wednesday) Issued at 159 PM MST Tue Jan 3 2017 A strong northwesterly flow aloft will be over the region through Wednesday. Expect persistent light to moderate snowfall in the mountains north of I-70. A strong 120+ kt upper level jet ahead of a storm system dropping out of the Pacific Northwest will move into northern CO by 00z Thu. There is good mid level qg ascent and still favorable mid level instabilities as well for the mountains. For areas in and near the Front Range Foothills, shallow upslope will be overrun by a strong jet aloft. Could see enhanced snow bands oriented northwest to southeast across the CWA by late Wednesday aftn. Have decided to upgrade the Winter Storm Watches to Warnings for zones 30, 32, 34 and 35. Due to the potential for heavy banded snowfall have also placed zones 36, 38 and 39 to Winter Storm Watches. This could adversely impact the Wednesday evening commute if any bands of convective symmetric instability crank up in the afternoon. As for tonight for the northeast plains, some low clouds are expected to be around with just isold light snow possible near the foothills...otherwise cold and dry. .LONG TERM...(Wednesday night through Tuesday) Issued at 159 PM MST Tue Jan 3 2017 Complicated winter pattern to start the year with moist West to Northwest flow ahead of an elongated upper trough moving South. Cold, arctic air will continue to move south over the region Wednesday afternoon behind a cold frontal boundary that will bring another surge of upslope favorable NE surface winds to the plains. The big players here will be the moisture available along with the upper jet and frontogenesis. This will provide for CSI potential and subsequent banding Wednesday night into Thursday morning. This banding could bring periods of intense snowfall and drop up to 1-2 inches in less than an hour. Have kept snowfall pops high in the mountains with the moisture levels and decent lift providing for continued accumulations into late Thursday with an additional foot or more possible in the high country. On the plains amounts will be higher closer to the Foothills and North of I-25 to the Wyoming border. Amounts of 2 to 5 inches will be possible for the plains East of DIA and 4 to 6 for areas west of DIA to include the I-25 corridor and south to Elbert county. As you go west of I-25 amounts will increase due to upslope. These amounts will be from 10 to 15 inches. Have issued a Winter Storm Watch for areas in Larimer and Weld county south into Boulder and Jefferson counties that will go from Wednesday afternoon to Thursday evening. Have advised the oncoming shift of a possible need for an advisory for the Denver Metro area east onto the plains for that time period due to the snow ratios and intensity possible with banding. Temperatures will be cold Thursday night with lows below zero and highs in the single digits. Precipitation over the area will end starting Friday morning from north to south as the upper trough sags southward. Temperatures will rebound slightly into the 20s with overnight lows continuing to be below zero. An upper ridge will move in over the weekend clearing out conditions and allowing for highs to rebound back to normal with possible upper 50s by Monday. The next weather maker will move in Tuesday with another round of snow possible for the mountains. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 524 PM MST Tue Jan 3 2017 Mid and upper level moisture will continue through 02z but could start to see mvfr/ifr cigs developing later this evening into Wednesday morning as northeasterly winds help to moisten the airmass and a weak Denver Cyclone wraps moisture into the area airports. A few light flurries could be seen early Wednesday morning however the bigger cold push isn't expected until later Wednesday afternoon for heavier snow restricting ceilings and visibilities. Snow bands will likely create narrow areas of low visibility and heavier snowfall rates.. Could see cigs blo 1kft and vsbys to 1/2mi by 00z Thu. Easterly winds his evening will cyclone around to the northeast and become light and variable at times, then stronger northeast on Wednesday, aob 10 kts for the most part. && .BOU WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning from 5 AM Wednesday to 11 AM MST Thursday for COZ030-032-035. Winter Storm Watch from Wednesday morning through Thursday afternoon for COZ036-038-039. Winter Weather Advisory until 6 PM MST this evening for COZ031- 033. Winter Storm Warning until 11 AM MST Thursday for COZ031-033-034. && SHORT TERM...Cooper LONG TERM...Bowen AVIATION...Kriederman
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER/BOULDER CO 546 AM MST TUE JAN 3 2017 COZ030>051-041300- 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- 546 AM MST TUE JAN 3 2017 ...WINTER STORM WARNING FOR THE MOUNTAINS NORTH OF I-70 TONIGHT THROUGH THURSDAY MORNING... ...WINTER STORM WATCH FOR THE MOUNTAINS ALONG AND SOUTH OF I-70 LATE TONIGHT THROUGH THURSDAY AFTERNOON... ...WINTER STORM WATCH FOR THE HIGHER VALLEYS AND NORTHERN FOOTHILLS FOR LATE TONIGHT THROUGH THURSDAY MORNING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT COLD AIR ASSOCIATED WITH A CANADIAN COLD FRONT HAS MOVED INTO NORTHERN COLORADO THIS MORNING. THIS WILL KEEP TEMPERATURES MUCH COOLER THAN NORMAL TODAY AND TONIGHT. IN THE MOUNTAINS, PACIFIC MOISTURE AND STRONG WESTERLY FLOW HAVE MOVED OVER THE REGION, CAUSING LIGHT TO MODERATE SNOWFALL. MOISTURE LEVELS WILL BE INCREASING FURTHER TONIGHT CAUSING SNOWFALL ACCUMULATIONS TO INCREASE, ESPECIALLY TO THE NORTH OF THE I-70 CORRIDOR. SNOW ACCUMULATIONS OF 2 TO 4 INCHES ARE EXPECTED TODAY WITH ANOTHER 3 TO 6 INCHES TONIGHT. MOUNTAIN TRAVEL MAY BE DIFFICULT TODAY AND TONIGHT DUE TO SNOW-COVERED ROADS AND POOR VISIBILITY IN FALLING SNOW. VARIOUS WINTER WEATHER ADVISORIES, WARNINGS AND WATCHES ARE IN EFFECT FOR THE NEXT FEW DAYS. ON THE PLAINS, A BAND OF SNOW ACROSS WELD AND MORGAN COUNTIES THIS MORNING SHOULD DISSIPATE BY LATE THIS MORNING. AREAS UNDER THE SNOW BAND MAY SEE A COUPLE INCHES OF ACCUMULATION BEFORE THE SNOW BAND BREAKS APART. HIGH TEMPERATURES NEAR THE NORTHERN BORDER MAY ONLY BE IN THE UPPER TEENS WHILE THE REST OF NORTHEAST COLORADO TOP OUT IN THE LOWER AND MID 20S. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE LOWER SINGLE DIGITS ACROSS MOST OF THE PLAINS TONIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY SNOW WILL CONTINUE IN THE MOUNTAINS AND HIGHER VALLEYS WEDNESDAY THROUGH THURSDAY WITH PERIODS OF HEAVY SNOW AT TIMES. ADDITIONAL ACCUMULATIONS WILL RANGE FROM 8 TO 16 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. THE HIGHER VALLEYS COULD SEE FROM 6 TO 12 INCHES OF SNOW. GUSTY WEST WINDS WILL PRODUCE AREAS OF BLOWING SNOW AND POOR VISIBLITIES OVER THE HIGHER PASSES. AT LOWER ELEVATIONS SNOW WILL INCREASE NEAR THE WYOMING BORDER WEDNESDAY MORNING AND THEN SPREAD SOUTHWARD BY AFTERNOON AS ANOTHER SHOT OF COLDER AIR MOVES ACROSS NORTHEAST COLORADO. HEAVY SNOW MAY OCCUR IN THE NORTHERN FOOTHILLS WEDNESDAY AND WEDNESDAY NIGHT WITH ACCUMULATIONS FROM 8 TO 16 INCHES POSSIBLE. THERE IS ALSO SOME POTENTIAL FOR HEAVY SNOW ALONG THE FRONT RANGE FROM DENVER NORTH TO THE WYOMING BORDER WEDNESDAY NIGHT. SNOW WILL CONTINUE INTO THURSDAY MORNING BUT SHOULD BEGIN TO DECREASE FROM NORTH TO SOUTH BY THURSDAY AFTERNOON. HOWEVER, TEMPERATURES WILL BE WELL BELOW NORMAL. ON FRIDAY THERE WILL BE A CHANCE OF LIGHT SNOW IN THE MOUNTAINS WITH ONLY A SLIGHT CHANCE AT LOWER ELEVATIONS. DRY CONDITIONS ALONG WITH A WARMING TREND ARE EXPECTED FOR THE WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.
The national radar mosaic for the moment the first event began.
8 winter storm, 1 winter weather. Local standard time, as filed.
Storm totals included: 38.7, 4 miles souitheast of Mt. Zirkel, 21.8 inches, 9 miles south-southeast of Spicer and 19 inches at Tower.
Storm totals included 12 inches near Stillwater Creek and 11 inches near Grand Lake.
Storm totals included: 17 inches at Deadman Hill, 13 inches at Willow Park and 12 inches at Long Draw Reservoir.
Storm totals included: 16 inches in Niwot Ridge, 14.5 inches, 5 miles west-southwest of Guanella Pass and 13.3 inches at Loveland Pass, 12 inches at Eldora, and Winter Park Ski Areas.
Storm totals included: 17 inches at Copeland Lake, 15 inches at Estes Park, 14.5 inches, 3 miles west of Jamestown; 14 inches at Allenspark and 12 inches at Gross Reservoir.
Storm totals included: 9 inches at Flatiron Reservoir, 7 inches near Loveland, with 5 inches at Colorado State University in Ft. Collins.
Storm totals included: 13.8 inches in Boulder, 12 inches in Marston Reservoir, 11 inches in Erie, 9.5 inches in Niwot, with 7 inches in Arvada and near Frederick.
Storm totals included 7 inches near Brighton and Westminster, with 6.7 inches near Northglenn.
Storm totals included 9 inches at Aspen Springs and Georgetown, with 5 inches in Bailey.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2017Every state in 2017This day in weather historyWarnings in Colorado, January 2017
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: 670138, 670139, 670140, 670141, 670142, 670143, 670144, 670145, 670146.