Temperatures continue to cool as we get further into fall and our look back at this week in Denver weather history provides some insight into the types of extreme weather that are possible this time of year. Noteworthy events include many incidences of damaging wind and some monstrous snowstorms.

From the National Weather Service:

18-23

In 2003…an extended warm spell resulted in 5 new temperature records. The high temperature of 84 degrees on the 18th equaled the record high for the date. High temperatures of 86 degrees on the 19th…83 degrees on the 21st…and 84 degrees on the 22nd were record highs for the dates. Low temperature of 49 degrees on the 23rd was a record high minimum for the date. Low temperatures during the period were in the 40’s and lower 50’s.

19-20

In 1990…an early winter storm dumped heavy snow across metro Denver. Snowfall amounts ranged from 4 to 8 inches in the foothills above 6500 feet elevation…4 to 7 inches in the Castle Rock area…and 2 to 5 inches across most of metro Denver and Boulder. Snowfall totaled 3.6 inches at Stapleton International Airport where northwest winds gusting to 48 mph kicked up some blowing dust shortly after a cold frontal passage on the 19th. However… Temperatures were warm enough to keep most roadways wet and slushy at lower elevations.

19-23

In 1906…heavy snowfall totaled 22.7 inches in the city over the 5 days. Rain changed to snow on the evening of the 19th…and snow continued through the late afternoon of the 23rd. The heaviest amount of snowfall…16.0 inches…fell from 8:00 pm on the 20th to 8:00 pm on the 22nd. The most snow on the ground was 13.3 inches on the evening of the 23rd. This was the first snow of the season and the only snow of the month. Winds during the storm were from the north at sustained speeds of 20 to 30 mph each day. Temperatures during the storm were generally in the 20’s.

20

In 1878…between 3:00 pm and 4:00 pm wind speeds averaged 48 mph with a maximum 1 minute sustained velocity to 96 mph at both 3:27 pm and 3:48 pm in downtown Denver. This is the highest sustained wind speed ever recorded in the city.

In 1986…a rare late October thunderstorm produced 3/4 inch diameter hail at Centennial Airport. Hail piled up 2 1/2 inches deep…causing some street flooding in south metro Denver.

In 2019…strong bora winds swept across the foothills and adjacent plains. Peak gusts included: 82 mph…3 miles southwest of Rocky Flats; 78 mph near White Ranch Open Space; 75 mph near Genesee and Georgetown; with 63 mph at Firestone. At Denver International Airport…a peak gust of 49 mph was observed from the west.

20-21

In 2007…a storm system brought heavy snow to the southern Denver suburbs as well as the Palmer Divide south of Denver. Storm totals included: 7.5 inches near Castle Rock…Lone Tree and Greenwood Village…with 6.5 inches at Elizabeth. Snow drifts up to 2 feet deep were observed 6 miles south-southwest of Elizabeth. In the Denver Stapleton area…2.0 inches of snow was observed.

In 2009…heavy snow developed along the Palmer Divide south and southeast of Denver as a storm system tracked across southern Colorado and northern New Mexico. Storm totals included: 15 inches…15 miles north of Elizabeth…9 inches…5 miles south-southwest of Arapahoe Park; 8 inches in Highlands Ranch…5 miles south- southeast of Sedalia; 6.5 inches…8 miles southwest of Bennett and 6 inches in Parker. At Denver international… Only 1.5 inches of snowfall was observed.

20-22

In 1936…5.5 inches of snow fell over downtown Denver. Most of the snow…4.5 inches…fell on the 20th.

21

In 1920…the rare event of snow from a thunderstorm occurred in the city during the evening. Brilliant flashes of lightning and loud peals of thunder were first noted at 7:35 pm. Light rain began falling at 8:30 pm…and light moist snow began falling a few minutes later. Some soft hail was also seen falling with the rain and snow…but both melted almost as fast as they fell. The hail only continued for a few minutes…and the rain and snow ceased about 9:40 pm. The snowfall was the first to occur in Denver this season. The amount of precipitation at the station measured only 0.01 inch…but heavier amounts were reported from other parts of the city. Snowfall was only a trace.

21-22

In 1978…heavy rain on the 21st changed to snow by daybreak on the 22nd and continued the rest of the day. This was the first measurable snowfall of the season…but totaled only 1.7 inches at Stapleton International Airport where east winds gusted to 29 mph. While only a trace of snow covered the ground…precipitation totaled 1.27 inches.

22

In 1878…winds were sustained to 42 mph.

In 1887…the first measurable snow of the season occurred… Ending the longest snow-free period in Denver…232 days… Since the last snow on March 5th.

In 1947…the first snow of the season totaled only 1.6 inches. Post-frontal north winds caused temperatures to plunge from a high of 60 degrees at midnight to a low of only 30 degrees 24 hours later. This was the only snow of the month.

In 1985…high winds gusting from 60 to 80 mph buffeted the Front Range foothills. The strongest reported wind gust was 89 mph in eastern Boulder. A treehouse east of Boulder was set on fire by a downed power line. Two people in Boulder were injured. A woman broke her arm when the strong winds knocked her to the ground. A carpenter in the city suffered a severely cut hand while he was trying to repair a roof that was being torn from a building. At Stapleton International Airport…northwest winds gusted to 41 mph.

In 2001…west-northwest winds gusting as high as 54 mph warmed the temperature to a high of 70 degrees at Denver International Airport.

22-23

In 1914…post-frontal rain changed to snow. Precipitation totaled 2.72 inches…most of which was in the form of moist snow which melted as it fell in the business section of the city. About 3 inches of snow was measured on lawns in the residential areas on the morning of the 24th. Official snowfall totaled only 0.4 inch downtown… But an estimated 8.0 inches of snow melted as it fell. North to northeast winds were sustained to 29 mph with gusts to 30 mph on both days.

In 1975…a vigorous cold front moving across metro Denver followed by strong northeast winds gusting to 52 mph produced billows of blowing dust and plunged the temperature 21 degrees in an hour. The surface visibility was reduced to 1/4 mile in blowing dust at Stapleton International Airport. The temperature cooled from a daily record high of 81 degrees to a low of 38 degrees by day’s end. The first snowfall of the season totaled 2.7 inches on the 23rd. This was the only measurable snow of the month at Stapleton International Airport.

In 1995…heavy snow fell on the Palmer Ridge south of Denver and in the foothills west of Denver where snow amounts ranged from 4 to 8 inches. Sedalia…south of Denver… Received 8 inches of snow. Winds strengthened on the plains and produced blizzard conditions…reducing surface visibilities to less than 1/4 mile. I-70 was closed from just east of Denver at Gun Club Road to the Kansas border. Ten inches of snow fell at Strasburg east of Denver where north winds at sustained speeds of 35 to 45 mph with gusts as high as 60 mph produced 2 to 4 foot drifts. Snowfall totaled only 2.2 inches at the site of the former Stapleton International Airport. North winds gusted to 51 mph at Denver International Airport.

Continue reading October 20 to October 26: This Week in Denver Weather History →

Certainly snow begins to enter the equation as we get further into the season and our look back at Denver weather history for the week shows many such notable events. Others including damaging winds and even a tornado and monstrous hail storm.

From the National Weather Service:

11-13

In 1892…apparent post-frontal rainfall totaled 3.33 inches in downtown Denver over the 3 days. A trace of snow on the 12th melted as it fell. Rainfall of 2.58 inches on the 12th into the 13th was the greatest 24-hour precipitation ever recorded during the month of October. Northwest winds were sustained to 48 mph with gusts as high as 55 mph on the 12th.

12-13

In 2001…overnight peak wind gusts to 82 mph and 70 mph were measured atop Niwot Ridge and Squaw Mountain… Respectively.

12-14

In 1969…record breaking extremely cold temperatures for so early in the season occurred. The high temperature of 26 degrees on the 13th was two degrees lower than the previous record minimum temperature of 28 degrees for the date set in 1885. The high temperature of 24 degrees on the 12th exceeded the record low temperature (22 degrees set in 1885) for the date by only 2 degrees. In addition… 3 new record low temperatures for the dates were set. The low temperature dipped to 10 degrees on the 12th breaking the old record (22 degrees in 1885) by 12 degrees. On the 13th the mercury plunged to a low of 3 degrees breaking the old record (28 degrees in 1885) by 25 degrees. On the 14th the temperature reached a minimum of 4 degrees breaking the old record (25 degrees in 1966) by 21 degrees.

13

In 1990…strong downslope winds stirred up clouds of dust and gravel…rattled windows…and stripped autumn-colored leaves from trees in Boulder. A wind gust to 78 mph was clocked in southwest Boulder…while a 96 mph gust was recorded in northwest Boulder. West winds gusted to only 36 mph at Stapleton International Airport.

13-14

In 1910…light smoke from nearby forest fires drifted over the city.

In 1966…the first measurable snow of the season caused widespread damage to trees and shrubs. The heavy wet snow totaled 6.9 inches at Stapleton International Airport where north-northwest winds sustained at 20 to 25 mph and gusting to 45 mph caused much blowing and drifting snow. South and east of Denver…up to a foot of snow fell. Heavy wet snow accumulations followed by freezing temperatures and strong winds resulted in extensive damage to trees…cars… And utility lines by falling limbs. A woman was killed by a falling snow laden tree limb in Denver. Several other people received minor injuries from falling tree limbs.

In 1987…rain drenched metro Denver. The South Platte Canyon area southwest of Denver received the most with 1.11 inches at Kassler and 1.49 inches upstream at Strontia Springs. At Stapleton International Airport…0.62 inch of rain was measured…northwest winds gusted to 29 mph…and thunder was heard.

In 2007…a new 24-hour record of 2.65 inches of precipitation was set at Denver International Airport for the month of October; breaking the previous record of 2.58 inches set in 1892.

13-16

In 1873…smoke from several large forest fires in the mountains made the air very hazy in the city.

14

In 1952…the first measurable snowfall of the season left 1.2 inches of snow at Stapleton Airport. North winds gusted to 38 mph.

In 1974…rain changed to snow early in the day…but snowfall totaled only 1.0 inch at Stapleton International Airport where northeast winds gusted to 20 mph.

In 2021…very strong wind gusts developed over the higher mountain areas. Peak wind gusts atop Berthoud Pass ranged from 90 to 104 mph. At Denver International Airport…a peak wind gust to 41 mph was observed from the northwest.

15

In 1871…a terrible wind occurred during a snow storm in the foothills above Boulder. Damage was minor.

In 1878…high winds reached sustained speeds of 60 mph at times.

In 1911…post-frontal northwest winds were sustained to 41 mph with gusts to 43 mph.

In 1948…strong winds struck the Boulder area. Winds averaged 50 mph at Valmont just east of Boulder. Wind gusts in excess of 60 mph were recorded at the Boulder airport. Wind gusts to 40 mph briefly reduced the visibility to 1 1/2 miles in blowing dust at Stapleton Airport.

In 1980…a rare October tornado touched down in Boulder… Damaging a vocational training building and throwing three nearby cars together damaging them extensively. A mile and half away several camper vehicles were thrown 200 feet. The storm also produced 1 inch diameter hail in the Boulder area.

15-16

In 1928…a thunderstorm produced hail shortly after midnight on the 15th. Rain changed to snow by evening. Through the afternoon of the 16th…the heavy snowfall totaled 7.3 inches in the city. North winds were sustained to 23 mph on the 15th.

In 1984…the heaviest October snowstorm in several years hit eastern Colorado with a vengeance. The storm was known as the “Bronco Blizzard” since it occurred during a nationally televised Monday Night Football game in Denver. One to two feet of snow fell near the foothills in west metro Denver with 2 to 3 feet in the foothills. Wind gusts up to 55 mph whipped the snow into drifts as high as 4 feet. The storm closed schools…roads…and airports. I-70 was closed both east and west of Denver. I-25 was closed south to Colorado Springs. Flights were delayed for several hours at Stapleton International Airport. Power outages were widespread. Snowfall totaled 9.2 inches at Stapleton International Airport where north winds gusting as high as 40 mph caused frequent surface visibilities of 1/4 to 1/2 mile in moderate to heavy snow and blowing snow overnight. The high temperature of only 35 degrees on the 15th was a record low maximum for the date.

Continue reading October 13 to October 19: This Week in Denver Weather History →

Wind is arguably one of the most annoying weather conditions and as our look back at this week in Denver weather history shows, it is often present this time of year. We also notice some decent shots of snow, including one in 2005 that brought nearly a foot to the Mile High City.

From the National Weather Service:

6

In 1900…northwest winds were sustained to 40 mph with gusts as high as 50 mph in downtown Denver.

In 1903…northwest winds were sustained to 40 mph with gusts to 50 mph. The strong winds warmed the temperature to a high of 71 degrees in the city. The low reading was only 46 degrees.

In 1910…light smoke from forest fires drifted over the city.

In 1976…an arctic cold front brought light snow over the foothills above 6 thousand feet. Traffic was snarled at many locations. Only a trace of snow fell at Stapleton International Airport where rainfall totaled 0.20 inch and northeast winds gusted to 41 mph.

In 1991…the brilliant orange sunset was apparently the result of an extensive volcanic smoke layer in the upper atmosphere.

In 1994…strong west to northwest winds developed in the foothills above 9500 feet. A wind gust to 78 mph was recorded atop squaw mountain west of Denver and to 72 mph at Ward northwest of Boulder. Northwest winds gusted to 35 mph at Stapleton International Airport.

In 2011…strong winds developed in and around the Denver area ahead of an approaching storm system. At the National Wind Technology Center…peak wind gusts ranged from 79 to 92 mph during the early morning hours. Across metro Denver…the strong winds toppled a few trees and damaged patio furniture. The wind caused a few flight delays at Denver International Airport due to a partial ground stoppage of incoming flights. Peak wind reports also included: 66 mph at Cedar Point…63 mph at Denver International Airport…60 mph at Buckley Air Force Base; 59 mph at Highlands Ranch; 58 mph at Deer Trail and Rocky Mountain Metro Airport in Broomfield; 55 mph at Bennett…Centennial Airport and City Park in Denver.

7

In 1903…north winds were sustained to 40 mph with gusts to 48 mph.

In 1917…post-frontal northwest winds were sustained to 45 mph with gusts to 52 mph. Rain was mixed with a trace of snow…the first of the season. Precipitation totaled 0.22 inch and included the occurrence of hail… Even though no thunder was heard.

In 1950…strong winds caused a power outage in Boulder. This was the heaviest windstorm since January. Damage was minor. Northwest winds gusted to only 35 mph at Stapleton Airport.

In 1985…strong Chinook winds buffeted the Front Range foothills. Wind gusts between 60 and 70 mph were reported in Boulder and atop Squaw Mountain west of Denver. Southwest winds gusted to 41 mph at Stapleton International Airport.

7-8

In 1990…the season’s first snow occurred. Snowfall amounts varied from 3 to 7 inches across metro Denver. Snowfall totaled 4.0 inches at Stapleton International Airport where north winds gusted to 29 mph.

8

In 1923…southeast winds were sustained to 44 mph with gusts to 47 mph. The strong winds persisted through the afternoon. The high temperature of 77 degrees was the warmest of the month that year.

In 1975…a wind gust to near 100 mph was recorded in Boulder. Frequent wind gusts to 60 mph were reported along the foothills causing only minor damage. West winds gusted to 45 mph at Stapleton International Airport.

8-9

In 2017…an early season snowstorm produced heavy wet snow which broke branches and downed power lines. About ninety-eight thousand outages occurred in Denver and the surrounding metro area. Almost half the outages were very short…while 54210 were sustained outages that lasted longer than five minutes. Some however lasted for several hours. Snow amounts varied greatly along the Interstate 25 Corridor. West of I-25…storm totals included: 7.5 inches in Arvada…7 inches in Broomfield…6 inches Boulder and Louisville…with 5 inches at Ralston Reservoir. East of I-25…storm totals ranged from a trace to 4 inches. In the mountains and foothills…storm totals included: 12.5 inches near Genesee…10 inches at Eldorado Springs… Idledale and Nederland…with 8.5 inches near Jamestown.

9

In 1910…light smoke from forest fires in the mountains was sighted over the city.

In 1982…northwest winds gusted to 49 mph at Stapleton International Airport.

9-10

In 2005…a major winter storm brought heavy…wet snowfall to the Front Range mountains…eastern foothills…portions of metro Denver…and the palmer divide. Snow accumulations ranged from 8 to 26 inches with drifts from 3 to 4 feet in places. The heaviest snow occurred to the east and southeast of the city…closing most major highways in that area…including I-70 from Denver to Limon. The Red Cross opened four shelters for people who were stranded along I-70 in eastern Colorado. Since many trees had not yet shed their leaves…the storm caused significant tree damage. One woman in Denver was killed when a tree branch… 8 to 10 inches in diameter…snapped under the weight of the heavy…wet snow and struck her as she was shoveling her driveway. Xcel Energy reported power outages to about 35 thousand customers. Several incoming flights were delayed at Denver International Airport. Snow totals included: 16 inches in the foothills near Boulder…12 inches at Genesee and near Golden…22 inches near Watkins…19 inches near Bennett…17 inches southeast of Aurora…14 inches near Parker…13 inches near Castle Rock…12 inches in Centennial… 11 inches in Parker…and 10 inches at Denver International Airport and in Littleton. While many areas of metro Denver received heavy snow…others experienced almost entirely rain. This included west and northwest metro Denver…Boulder…and Longmont. Rainfall amounts were significant as storm totals ranged between 1.50 and 2.50 inches. The steady rainfall triggered 3 rockslides in foothills canyons. Two of the slides occurred on State Highway 119 in Boulder Canyon and the longest slide…7 feet in length…on State Highway 74 in Bear Creek Canyon at Idledale. North winds were sustained to around 23 mph with gusts to 31 mph at Denver International Airport on the 9th. The high temperature of only 34 degrees on the 10th was a record low maximum for the date. The low temperature on both days was 32 degrees.

In 2019…a vigorous winter like storm system brought intense northerly winds and the cold front blasted through the urban corridor. Peak wind gusts from 50 to 60 mph accompanied the front. Some trees in Denver were uprooted by the strong winds. Light rain and drizzle overnight…changed over to the season`s first snow during the predawn hours of the 10th. Bands of moderate to heavy snow brought 2 to 6 inches of snow in the Front Range mountains…foothills and urban corridor. The morning commute was especially hazardous as falling temperatures froze wet roads. Multiple crashes occurred including: I-25 in Denver…I-70 from Denver west to the Eisenhower Tunnel and State Highway 285 towards Fairplay. Over 300 crashes were reported in Denver and Aurora alone. After reaching a maximum temperatures of 83 degrees on the afternoon of the 9th…the temperature plummeted to 13 degrees on the 10th. A temperature change of 70 degrees…the second largest 2-day swing for the month of October in Denver weather history.

Continue reading October 6 to October 12: This Week in Denver Weather History →