Hurricane force winds toppled trees and knocked over several semis in and near the Front Range Mountains and Foothills. The Colorado Department of Transportation shut down Interstate 70 in both directions for a short time late between Beaver Brook and Silverthorne.
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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.
Hurricane force winds toppled trees and knocked over several semis in and near the Front Range Mountains and Foothills. The Colorado Department of Transportation shut down Interstate 70 in both directions for a short time late between Beaver Brook and Silverthorne. Several trucks had been blown over and some cars received shattered windshields. High-profile vehicles and semi-trucks were barred from that area of the interstate until the wind weakened. Two trucks also rolled over on I-70 in Georgetown. The wind toppled dozens of trees near Estes Park and Glen Haven. In Glen Haven, two sheds and several decks were damaged by fallen trees. Downed power lines caused scattered electrical outages in Boulder and Larimer Counties. Nearly four thousand residents in Boulder County were left without power. The temperature in Denver reached 80 degrees. It was the first 80 degree temperature recorded in the month of February and established the all-time record for the month. The high wind and extremely warm temperatures helped to spread three grassfires in Boulder and Larimer Counties; no homes were damaged or lost. Intense wind gusts on the 10th caused power outages and damage to trees, fences and power lines across Boulder County. Blowing dirt reduced visibilities to a quarter-of-a-mile at times. A strong burst of wind uprooted trees, and knocked down an entire row of power poles and lines near Main Street and Pike Road in Longmont. The downed lines damaged a vehicle at one residence. Another resident had to be rescued when he was trapped in his car by downed electrical lines.
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 Feb 9, 3:08 PM MST, 5 hours 52 minutes earlier.
Area Forecast Discussion National Weather Service Denver/Boulder CO 308 PM MST Thu Feb 9 2017 .SHORT TERM...(This evening through Friday) Issued at 308 PM MST Thu Feb 9 2017 Warm temperatures have prevailed across the plains this afternoon as upper ridging built over the state and a lee trough emerged at the surface. Cloud cover and snow showers over the mountains have been decreasing through the day. Further drying will occur overnight. For Friday...strong flow aloft will become more southwesterly through the day as moisture begins increasing in the mountains. Model cross sections show very strong winds over ridgetops by tomorrow afternoon, but the west-southwest wind direction will not favor a widespread wind event. The Palmer Divide should have the gustiest winds, up to 25 or 30 mph. Temperatures are expected to be 5 to 10 degrees warmer than this afternoon, into the mid 70s across the plains. The combination of gusty winds, warm temperatures and low humidities will cause the fire dangers to be elevated, mainly in Douglas and Lincoln Counties. During the afternoon, the arrival of deeper moisture in the mountains will lead to the onset of the next snow storm for the mountains. However, freezing levels are going to be starting out quite high, and mountain areas may see a little bit of rain before changing over to snow. Plains locations will remain dry and warm through the afternoon. .LONG TERM...(Friday night through Thursday) Issued at 308 PM MST Thu Feb 9 2017 A trough of low pressure just off the west coast of CA will increase SW flow over the Great Basin for the weekend. Moisture will increase across the high country and western portions of the state late Friday bringing precipitation to the mountains as early as Friday night and continuing through Saturday night. Temperatures at 700 mb show a rain and snow mix early Saturday before cooler air moves in by Saturday late afternoon and continue into the evening hours. At this time amounts are borderline for any hilites but will need to assess any changes over the next 24 hours. For the plains an inverted trough will help to keep any precipitation out until a cold frontal push from the North in the afternoon on Saturday. This frontal push will bring moisture and lower temperatures by late Saturday. Snow will become likely over the central plains by early Sunday. Precipitation will start as rain or a rain and snow mix before turning to snow by early Sunday. Snow ratios will be high given the temperature profile so dense snow is possible with lower snow amounts...especially after a warmer then average week previous. Temperatures will be upwards of 20 degrees cooler Friday into Saturday with the cold front. Highs are expected to be in the 50s for Saturday and 40s on Sunday. Overnight lows on Saturday will to drop below freezing so any wet rain/snow accumulation on roads and sidewalks will freeze overnight. By Sunday evening drying behind the front with increasing subsidence will help to clear out conditions quickly. This will be the start of a short dry period with increasing pressure from an upper level ridge. Temperatures for Monday through Wednesday will stay in the 50s with lower 60s possible by Wednesday under partly cloudy skies. Toward the end of the week models differ on a small disturbance in the flow that could bring some precipitation so have kept chances low and isolated to the mountains at this time. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 308 PM MST Thu Feb 9 2017 Gusty west to southwest winds at times will be the primary aviation concern through the next 24 hours. Gusts ranging from 20 to 30 knots at times will be possible. KBJC will see the most gusts this evening and KAPA may see a bit more gusty winds tomorrow as the flow pattern aloft will be transitioning to southwesterly. Ceilings and visibilities will remain unlimited. && .FIRE WEATHER... Issued at 308 PM MST Thu Feb 9 2017 Temperatures climbing to the upper 60s to mid 70s will drive down humidity levels to 15 to 20 percent. Gusty southwest winds are also expected to develop across the Palmer Divide region at speeds up to 20 to 30 mph. Marginal Red Flag conditions are forecast for a couple hours tomorrow afternoon. Fuels in their dormant state are also dry and cured, ready to burn if a fire gets started. Will issue a Fire Weather Watch for now. If later forecasts indicate stronger winds tomorrow afternoon, then a Red Flag Warning may be necessary. && .BOU WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Friday morning through Friday afternoon for COZ241-246-247. && SHORT TERM...Dankers LONG TERM...Bowen AVIATION...Dankers FIRE WEATHER...Dankers
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER/BOULDER CO 1057 AM MST Thu Feb 9 2017 COZ030>051-101800- 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- 1057 AM MST Thu Feb 9 2017 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT Gusty and erratic chinook winds in the 30 to 45 mph range can be expected today in and near the foothills. Areas above timberline will also continue experiencing gusty west winds in the 40 to 50 mph range. Otherwise it will be dry and warmer day with afternoon temperatures up to 25 degrees warmer than average for the date. The unseasonably warm temperatures and low humidity will combine with gusty south winds at times to raise the wildland fire danger on the plains, particularly over the Palmer Divide. Tonight...west winds are expected to strengthen in the mountains and along the east slopes of the Front Range. Above timberline, wind gusts could approach 80 mph after midnight, which will produce considerable blowing and drifting snow. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY Expect strong and gusty winds over the high mountain passes on Friday with speeds up to 70 mph possible. Across lower elevations, temperatures will be warmer with record high temperatures possible with highs in the mid 70s. The abnormally warm temperatures, coupled with gusty southwest winds and lower relative humidity will elevate the wildland fire danger on the plains; particularly across Elbert and Lincoln counties Friday afternoon. Over the weekend...expect a return to cooler temperatures, with rain and snow likely in the mountains and high valleys Friday night and Saturday, and then rain and some snow possible over the entire outlook area behind a cold front Saturday night. It should then dry out from north to south on Sunday, but remain cool. It will remain dry early next week with temperatures warming to above average beneath a ridge of high pressure. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be required today or tonight.
The national radar mosaic for the moment the first event began.
3 high wind. Local standard time, as filed.
High winds uprooted trees and downed power lines. A tree fell on a parked vehicle. Downed electrical lines trapped a motorist in his vehicle until help arrived.
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, February 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: 669421, 669424, 671850.