Deep moisture and a strong jet stream brought another wave of heavy snow and strong winds to the mountains of north central Colorado. 5 inches, 3 miles south of Brainard Lake, 7 miles east-southeast of Cameron Pass and 9 miles south-southeast of Spicer; 12 inches, 4 miles south of Longs Peak and 3 miles north-northeast of Mount Audubon; 10 inches, 9 miles east of Glendevey and 9 miles…
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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.
Deep moisture and a strong jet stream brought another wave of heavy snow and strong winds to the mountains of north central Colorado. Storm totals included: 22 inches near Loveland Pass, 20.5 inches, 4 miles southeast of Mount Zirkel; 18.5 inches near Climax; 15.5 inches near Copper Mountain, Eldora and 5 miles west-southwest of Guanella Pass; 13.5 inches, 3 miles south of Brainard Lake, 7 miles east-southeast of Cameron Pass and 9 miles south-southeast of Spicer; 12 inches, 4 miles south of Longs Peak and 3 miles north-northeast of Mount Audubon; 10 inches, 9 miles east of Glendevey and 9 miles south-southeast of Gould. Gusty winds were also observed, ranging from 45 to 55 mph above timberline.
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 24, 8:45 PM MST, 2 hours 15 minutes earlier.
Area Forecast Discussion National Weather Service Denver/Boulder CO 845 PM MST Sun Dec 24 2017 .UPDATE... Issued at 845 PM MST Sun Dec 24 2017 Forecast is on track. Only minor adjustments to overnight low temperatures and PoP trends. Current radar and observations show snow blossoming along the Wasatch Front in Utah, so developing light snow in the mountains late this evening will increase in intensity and become heavy at times overnight into early Christmas morning. Upstream 00Z observations showed Precipitable Water (PW) near 0.50 inch at Elko, so there's a good stream of moisture which should result in healthy QPF amounts. Sometimes these patterns lend to lower snow ratios, so will have to watch that a bit for total accumulations, but latest check still shows a good dendritic growth regime. Strong winds will produce considerable blowing and drifting snow and hazardous travel, with the worst conditions late tonight and Monday morning. Winter Storm Warnings and Advisories for the high country remain on course, starting at 11 PM tonight and continuing through Christmas evening. On the plains, we have likely reached or at least come close to overnight lows with plenty of mid/upper level moisture streaming across the area. Main change was to increase PoPs for the northern border area tomorrow to match up with expected band of precipitation in that area. Could see a dusting to 2" north of Wellington to Sterling line through tomorrow evening. Precip chances in the Denver metro area appear quite low with too much downslope. There is a weak easterly push tomorrow, but only very shallow upslope noted at this time. && .SHORT TERM...(This evening through Monday) Issued at 223 PM MST Sun Dec 24 2017 A 120 plus knot Pacific jet and the large lift it generates noses into western Colorado this evening, accompanied by the leading edge of relatively deep plume of moisture of maritime origin. In addition, strong westerly 750-600 flow will generate orographic snowfall over windward facing slopes across the nrn mtn ranges beginning as light intensity this evening. It is after midnight tonight when snowfall should become widespread, mainly up around timberline and west facing mtn slopes when sfc-500mb QG ascent peaks and moisture deepens under the front left quad of the jet. Areas east of the mtns will remain under the influence of downslope drying with this westerly flow. However, could see snow flurries or even some light snow blow off the Front Range and onto the nearby plains late tonight, but no resulting accumulation. Could see snowfall rates along and west of the Continental Divide in the 2-3 inch per hour range late tonight through early Monday morning, and with 30-50 mph wind gusts producing blowing and drifting snow, travel will be most troublesome over the higher passes and up around the Eisenhower Tunnel. Should see a gradually southward migration in this jet enhanced snow band beginning up near the Wyoming border and ending up in the Summit and Park County mtn ranges by late Monday morning. On Monday, snow intensities across the high country should drop off, but strong nwly winds and moderate snowfall largely the product of orographic forcing should continue though the day on west and northwest facing slopes. Mtn valleys could also see some light accumulation. Even with snowfall rates generally under an inch per hour, the combo of wind and snow warrants holding onto the Winter Storm Warning for the northern mtn zones 31 and 33 and the central mtn zone 34. On the plains...models show a weak sfc cyclone forming east of Limon early and slowly migrating west towards the Denver metro area through the morning. A weak boundary rapping around this low is progged to swing south across the plains and into the Denver area by around mid-morning. Latest iteration of the HiRes models now picking up on a bit more low-level moisture with this surge, but still not indicating any QPF. It's later in the day when models indicate a deeper nely flow and the potential for scattered light snowfall across the nern corner and northern border area of the CWA as the area will be under weak QG ascent. Also looks like the nern counties will sock in with low upslope clouds during the afternoon which will further hold temperatures down out there. Speaking of temperatures, not counting on much warming anywhere tomorrow, perhaps no more than 3-5 degrees. Palmer Divide and South Park areas may be the only places where max temps exceed the freezing mark. .LONG TERM...(Monday night through Sunday) Issued at 223 PM MST Sun Dec 24 2017 Upper level ridging over the eastern Pacific and a long wave trough over eastern North American will keep a northwesterly flow aloft over Colorado through the upcoming week. This ridge will shift slightly east of where it has been positioned and should push the main storm track off to the northeast of Colorado. Mountain snow will decrease/end Monday night with this eastward shift of the ridge bringing drier air. For Tuesday through Thursday...cooler air is expected to remain over northern parts of the area with highs in the 20 to lower 30s. Other than a few flurries over far northern Colorado, dry conditions will prevail. A lee side trough forms Wednesday over eastern Colorado. This is expected to bring warmer temperatures. However east of the trough over far northeast Colorado, there is a chance the cooler air remains in place. Will have a large temperature gradient across the area on Wednesday. The lee side trough is expected to push east of the area Thursday and should result in warmer conditions for the entire area. As far as precipitation goes, models vary on the timing of the increases in moisture which may bring light snow to the northern mountains. The GFS shows light snow on Wednesday, while the ECMWF hints at a little mountain snow Thursday. Will have low pops for this each day. For Friday through next weekend, confidence in the forecast is on the low side. Models differ on the strength a short wave trough embedded in the northwest flow. If it digs far enough south, as the GFE shows, cold and snow is likely for the area. The ECMWF is weaker and drier, but still shows a glancing shot of arctic air for Saturday. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 845 PM MST Sun Dec 24 2017 Weak cyclone type flow in place has shifted KDEN around the west. Overnight, expect more of a southwesterly flow developing. Then, winds should turn northeasterly 13Z-17Z Monday and increase to 8-12 knots behind a weak frontal surge. VFR ceilings and visibilities will prevail through 12Z Monday, then some chance of ILS approaches with clouds lowering to 5000-6000 feet as plume of mid level moisture moves across. At this time, don't see enough low level moisture for much threat of lower MVFR ceilings or any light snow. && .BOU WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 11 PM MST Monday for COZ034. Winter Storm Warning until 11 PM MST Monday for COZ031-033. && UPDATE...Barjenbruch SHORT TERM...Baker LONG TERM...Meier AVIATION...Barjenbruch
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 1033 AM MST Sun Dec 24 2017 COZ030>051-251745- 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- 1033 AM MST Sun Dec 24 2017 ...A Blast of Snow and Strong Winds On the Way for the High Country Late Tonight Through Monday Morning... This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Strong westerly winds will continue on the mountain peaks and ridges generally up around timberline for the remainder of today. These areas will see gusts in the 35 to 50 mph range, with even stronger gusts to near 70 mph possible in open terrain above timberline. The winds will cause blowing snow and some drifting in open areas, as well as dangerous wind chills in the 20 to 30 below zero range. However, with warmer temperatures this afternoon, these wind chills will rise. Tonight...Look for snowfall to develop in the mountains this evening and will become widespread after midnight. Mountain tops and higher west and northwest facing slopes could see a period of heavy snowfall late tonight with several inches of snow accumulation likely by morning. Winds of 20 to 35 mph and gusts to 50 mph will also produce areas of blowing and drifting snow potentially resulting in hazardous winter driving conditions over the higher passes and up around the Eisenhower Tunnel. On the plains, temperatures will remain quite cold today even with mostly sunny skies. However temperatures tonight are not expected to be as cold with an increase in cloud cover. .DAYS TWO THROUGH SEVEN...Monday through Saturday Heavy snow will continue over the mountains Christmas day and decrease Christmas night. Total snow accumulations for the mountains are expected to be 6 to 16 inches with locally up to 20 inches. The heaviest snow will be found in the mountains north of Interstate 70. Roads are expected to become snow packed and slippery making for difficult travel. Light snow may fall Christmas and Christmas night over far northern Colorado. This may result in light snow cover on roadways. Light snow will be possible over the north central mountains Wednesday night and Thursday. Otherwise, dry conditions are expected to the later part of the upcoming week. .SPOTTER INFORMATION STATEMENT... Reports of snowfall or strong winds will be appreciated. Baker/Meier
The national radar mosaic for the moment the first event began.
3 winter storm. Local standard time, as filed.
Storm totals ranged from 10 to 20.5 inches.
Storm totals ranged from 8 to 14 inches.
Storm totals ranged from 12 to 22 inches.
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, December 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: 730800, 730801, 730802.