October 10 to October 16: This week in Denver weather history

This Week in Denver Weather History

The farther we get into fall the more we start seeing significant snow events in our look back at the week in history.  None of these is more famous than the “Bronco Blizzard” of 1984 that saw the Mile High City buried under nearly a foot of snow – on live television.

From the National Weather Service:

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.

10

In 1901…an evening thunderstorm produced east winds to 43 mph with gusts to 48 mph.

In 1949…strong winds believed to be the worst in Boulder’s history at the time caused over 100 thousand dollars damage in the city.  Peak winds were estimated to 85 mph at Valmont…just east of Boulder.  High winds also occurred over most of metro Denver and caused damage to trees…window glass…and utility lines.  The damage was most pronounced over the northwest metro area…including north Denver and Lakewood.  Falling tree branches caused damage to parked autos and houses.  Wind gusts to 70 mph were recorded at Stapleton Airport.

In 1964…lightning struck and killed a 13-year-old boy…while he was riding his bicycle along a tree-lined residential street in south Denver.  Apparent microburst winds gusted to 54 mph at Stapleton International Airport.

10-11

in 1986…the first significant snowstorm of the season produced 2 to 5 inches of snow over metro Denver with 5 to 10 inches in the foothills west of Denver.  Wondervu recorded the most snow from the storm…13 inches.  The heavy wet snow caused numerous power outages.  The storm was accompanied by strong north winds with gusts to 41 mph recorded on the 10th.  The first snowfall of the season totaled 3.1 inches at Stapleton International Airport with only one inch on the ground due to melting.  The strong cold front accompanying the storm cooled the temperature from a high of 73 degrees on the 10th to a high of only 33 degrees on the 11th…which was a record low maximum for the date.

10-12

In 1969…the second heavy snowstorm in less than a week dumped nearly a foot of snow across metro Denver and plunged the area into extremely cold temperatures for so early in the season.  Snowfall totaled 11.0 inches at Stapleton International Airport.  North winds gusting to 26 mph produced drifts up to 2 feet deep.  Temperatures dipped from a high of 52 degrees on the 10th to a record low for the date of 10 degrees on the 12th.  There was additional damage to trees and power and telephone lines from heavy snow accumulations and icing.  Travel was restricted or blocked by drifting snow in both the mountains and on the plains east of Denver.

11

In 1997…damaging winds ahead of an approaching storm system developed in the foothills and spread across metro Denver. Winds gusted to 88 mph at conifer…71 mph at the National Center for Atmospheric Research on the mesa in Boulder… And 53 mph at Denver International Airport.  Several trees and street signs were blown down with scattered power outages reported throughout metro Denver. In Arvada…a car window was blown out by a strong wind gust.

In 2013…high winds occurred in and near the Front Range Foothills. Peak gusts included: 85 mph at Rooney Road… 84 mph…2 miles south of Marshall; 82 mph at Rocky Flats National Wind Technology Center and Wondervu; 79 mph at the Mesa Lab at NCAR and 75 mph…3 miles south-southwest of Boulder; 73 mph in Superior and 68 mph in Golden. The wind downed trees and power lines. As a result…scattered electrical outages affected 20000 Xcel Energy customers through the morning hours. The main outages affected the cities of Boulder…Golden and Lakewood. Smaller outages were reported in areas of Gold Hill…Ward…Westminster and Wheat Ridge.

11-12

In 1901…an apparent cold front produced northeast winds sustained to 42 mph with gusts to 48 mph on the 11th. General rain changed to snow overnight and totaled 2.0 inches.  This was the first snowfall of the season. Total precipitation was 0.32 inch.

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

In 1873…smoke from several very large forest fires was sighted along the mountains.

In 1923…post-frontal rain changed to snow and totaled 4.0 inches.  North winds were sustained to 14 mph.

In 1978…northeast winds gusting to 35 mph with a strong cold front briefly reduced visibility to 2 miles in blowing dust at Stapleton International Airport.

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.

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.

15-17

In 1989…an autumn snowstorm hit metro Denver with 2 to 6 inches of snow.  Snowfall totaled 4.4 inches at Stapleton International Airport where the maximum snow depth on the ground was only 3 inches due to melting and north winds gusted to 25 mph on the 15th.  The heavy wet snow caused leafy branches to sag onto power lines…resulting in a number of power outages.  Five thousand homes were blacked out in Boulder on the 16th.  Up to a foot of snow fell in the higher foothills with 19 inches recorded at Echo Lake.

Continue reading October 10 to October 16: This week in Denver weather history

Leaf peeping 2021: When and where to see the fall colors

Rocky Mountain National Park is a prime spot for viewing the fall foliage. (Tony's Takes)
Rocky Mountain National Park is a prime spot for viewing the fall foliage. (Tony’s Takes)

This time of year many folks start thinking about heading to the hills west of Denver in search of gold – fall foliage gold.

Where to go?  Below are five of ThorntonWeather.com’s favorite ones near Denver – plus a few further out and some bonus ideas.  After that, we will tell you where you can find a great website that provides regular updates on viewing conditions.

I-70 Corridor – If you’re looking for the easiest route, then this one is for you.  Simply head west on I-70 about 110 miles to Avon.  Between Vail and Avon, both sides of I-70 are lined beautifully with aspen.

Rocky Mountain National Park – One of the most popular summer destinations in the state is of course also a prime spot to view aspen in all their glory.  Once in the park head toward Bear Lake.  Glacier Gorge Junction provides a beautiful spot and you of course also get to enjoy all the splendor that Rocky Mountain National Park has to offer.  Extend your viewing by taking Trail Ridge Road all the way through to the west side of the park and the Grand Lake and Granby area.

Peak to Peak Highway – This little road trip can be a dual purpose trip – gambling and fall foliage viewing!  Take U.S. 6 through Clear Creek Canyon and then 119 through Blackhawk and Central City.  You can of course stop there if your wallet is fat enough and donate some money to the casinos.  From there continue on 119 toward Nederland.  Take highway 72 toward Ward and Allenspark.  There you will find more golden aspen than you can imagine, all with the Continental Divide nearby.

Colorado Fall Foliage - Average Date of Peak Aspen Colors. Click for larger view. (ThorntonWeather.com)
Colorado Fall Foliage – Average Date of Peak Aspen Colors. Click for larger view. (ThorntonWeather.com)

Poudre Valley Canyon –  Heading north on I-25 take Colorado 14 west and into Poudre Canyon and Roosevelt National Forest.  As you continue west you will come very near timberline as you come to Cameron Pass.  Amazing views abound!

Guanella Pass – This is a nice, relatively short drive from Denver.  From C470 take 85 through Bailey and Conifer, a nice drive unto itself.  When you come to the town of Grant, take the Guanella Pass Scenic and Historic Byway north to Georgetown.  The air is pretty thin along the way as you climb in excess of 11,500 views through the Pike and Arapahoe National Forests.

A couple other possibilities further from the Front Range:

Leadville / Aspen – From Denver take I-70 west to Copper Mountain and then Colorado 91 south over Freemont Pass to Leadville. Along the way there are plenty of viewing opportunities and Leadville is a nice little town to make a stop. From here you can take Highway 24 north back through Minturn and Vail. To extend the drive, take Highway 24 south to Colorado 82 and head toward Aspen. You can stop by the Maroon Bells in White River National Forest to view some of the most photographed mountains in Colorado.

Cottonwood Pass – From Denver take Highway 285 to Buena Vista. Head west on Main Street for seven miles then west on County Road 344 / Colorado 82. From there you start the climb up Cottonwood Pass with absolutely stunning views from the top. If you are up for it, you can continue down the west side of the pass into the Taylor Park area.

Honorable mentions worth considering:

  • Boreas Pass between Breckenridge and Como (County Road 10)
  • Kenosha Pass on Highway 285 between Bailey and Fairplay
  • Independence Pass (Colorado 82 between Aspen and Twin Lakes)
  • Colorado 103 from Evergreen to Echo Lake. Throw in a drive up Mount Evans for a bonus.

If you do head out, be sure to send us your pictures for inclusion in our monthly photo slideshows!

For more information:

Thornton’s October 2021 preview: Generally calm conditions with our first freeze and snow

Thornton, Colorado October weather preview.With the first full month of fall here, October usually brings one of the quietest weather months in the Denver area with plenty of mild, sunny days and clear, cool nights.

October is historically the second sunniest month and conditions are generally calm.

However we also will usually see our first taste of winter during the month with the first freeze and first snowfall of the season.  Temperatures as well will start to drop and by the end of the month the average nighttime lows are below freezing.

For complete details on our historical October weather and what we can expect in the coming month, read our complete October weather preview here.

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October 3 to October 9: This week in Denver weather history

This Week in Denver Weather History

The first half of October historically is quiet for the most part but there have been years with plenty of excitement.  We have seen damaging tornadoes and winds and of course significant snowstorms.

From the National Weather Service:

3

In 1875…very dense haze hid the mountains from view as observed from the city.

In 1933…rainfall of just 0.01 inch was the only precipitation of the month.  This was the second driest October on record.

In 1954…the low temperature cooled to only 60 degrees…the all-time record high minimum for the month October.

3-4

In 1969…the first snowfall of the season totaled 16.0 inches at Stapleton International Airport.  There was a thunder snow shower on the evening of the 3rd…but otherwise little wind with the storm.  The greatest snow depth on the ground was 8 inches due to melting.  Heavy wet snow accumulated on trees…which were still in full leaf…and caused widespread damage from broken limbs and downed utility lines.

3-5

In 1984…the remnants of Pacific Hurricane Polo produced heavy rain over northeastern Colorado.  Most locations received between 1.00 to 2.50 inches of rain…but 3.45 inches fell in Littleton.  Rainfall totaled 1.73 inches at Stapleton International Airport…where north winds gusted to 24 mph.

4

In 1912…sustained south winds to 55 mph with gusts to 60 mph raised the temperature to a high of 83 degrees… The warmest temperature of the month that year.

In 1924…west winds were sustained to 46 mph with gusts to 50 mph in the city.  The apparent Bora winds cooled the temperature to a high of 57 degrees from a high of 70 degrees on the 3rd.

In 2004…several small tornadoes touched down near Brighton… Barr Lake…and Hudson in Adams and southern Weld counties. Most of these caused no damage.  However…a small tornado 5 miles southeast of Brighton caused extensive damage to a recreational vehicle and severely damaged a barn.  The barn was torn from its foundation…and the roof was thrown 100 feet.  Four llamas in the barn were injured when it collapsed.

4-5

In 1997…unusually warm weather resulted in two temperature records.  High temperature of 87 degrees on the 4th exceeded the old record set in 1922 by one degree.  High temperature of 86 degrees on the 5th equaled the record set in 1990 and previous years.

5

In 1962…unusually severe thunderstorms for this late in the season affected areas from Boulder northward.  Hail up to golf ball size and strong gusty winds did much damage to roofs…windows…and signs in Boulder.  Heavy rainfall caused local flooding.

In 1994…lightning caused a power outage to over 2400 homes for a few hours in and around Nederland in the foothills southwest of Boulder.  Very strong winds accompanied the thunderstorm.  Thunderstorm winds gusted to 60 mph and hail to 1/2 inch diameter fell in Lafayette.  Strong microburst winds gusting to 69 mph near Strasburg caused an oil rig to topple onto two vehicles…injuring one person.  The strong winds in the area also downed a few power poles… But caused power outages to only a few homes.

In 1995…strong winds spread from the foothills onto the plains.  Wind gusts to 77 mph were reported atop Squaw Mountain west of Denver.  On the plains…winds gusted to 60 mph at Kennesburg and to 62 mph near Strasburg. North winds gusted to 41 mph at Denver International Airport.

Continue reading October 3 to October 9: This week in Denver weather history

September 2021 top shots: Monthly photo slideshow

The sun rises in the Colorado high country. (Ed Dalton)
The sun rises in the Colorado high country. (Ed Dalton)

The month of September is typically one of the more pleasant months in Colorado.  Temperatures are usually comfortable and there is not normally a lot of weather drama.  That however does not mean there aren’t plenty of photo opportunities.

Wildlife is still quite active along the Front Range and flowers will hold on to their petals for at least the first part of the month.  Then of course there is the weather which you never know what to expect.  Thunderstorms, heavy rain, and even snow are a possibility.

  • Slideshow updated September 29, 2021
  • To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.

Showcasing images captured by ThorntonWeather.com readers as well as some of our own, our monthly slideshow covers the entire gamut of weather-related imagery.

Sunsets, sunrises, wildlife and of course every type of weather condition are vividly depicted in images captured from yours and our cameras.

[flickr_set id=”72157719829786238″]

What is missing in the slideshow above?  Your photo!

Our monthly photo slideshow is going to feature images that we have taken but more importantly images that you have captured.  The photos can be of anything even remotely weather-related.

Landscapes, current conditions, wildlife, pets, kids.  Whimsical, newsy, artsy.  Taken at the zoo, some other area attraction, a local park, a national park or your backyard.  You name it, we want to see and share it!

Images can be taken in Thornton, Denver or anywhere across the extraordinary Centennial State.  We’ll even take some from out of state if we can tie it to Colorado somehow.

We’ll keep the criteria very open to interpretation with just about any image eligible to be shown in our slideshows.

What do you win for having your image in our slideshow?  We are just a ‘mom and pop’ outfit and make no money from our site so we really don’t have the means to provide prizes.  However you will have our undying gratitude and the satisfaction that your images are shared on the most popular website in Thornton.

To share you images with us and get them included in the slideshow just email them to us or share them with ThorntonWeather.com on any of the various social media outlets.  Links are provided below.

So come on, get those camera’s rolling!

September 26 to October 2: This week in Denver weather history

This Week in Denver Weather History

Denver has been graced with an unusually mild September this year.  That however is not always the case and in fact the weather can be downright winterish as we see in our look back at this week in Denver weather history.

25-26

In 1908…apparent post-frontal rain changed to snow overnight and totaled 6.5 inches in downtown Denver.  This was the first snow of the season.  Precipitation totaled 0.76 inch. North winds were sustained to 39 mph on the 25th.

25-27

In 1996…an early season snowstorm brought heavy snow to the Front Range eastern foothills.  Snowfall totals included:  8 to 12 inches around conifer…7 inches on Floyd Hill…and 6 inches at both Bailey and Chief Hosa. Snowfall totaled only 4.7 inches at the site of the former Stapleton International Airport.  This was the first measurable snow of the season.  After the passage of a strong cold front…north winds gusted to 38 mph at Denver International Airport on the 25th.

26

In 1907…a late afternoon thunderstorm produced hail…0.23 inch of precipitation…and north winds sustained to 24 mph.

In 1927…snowfall of 1.7 inches…mixed at times with sleet… Was the first measurable snowfall of the season.

In 2012…a man was seriously injured when he was struck by lightning outside the Hebrew Educational Alliance as he and his family were getting in their car. The victim stopped breathing but was saved when his wife performed cardiopulmonary resuscitation on him immediately following the lightning strike. He suffered burns to 15 percent of his body which included his legs…chest… abdomen and neck. Lightning also caused 48 outages in Denver which affected 6582 Xcel Energy customers.

26-28

In 1936…the heaviest snowfall ever recorded in September and the heaviest snowfall ever recorded so early in the season dumped a total of 16.5 inches of snow on downtown Denver and 21.3 inches at Denver municipal airport.  The 15.0 inches of snow measured from 6:00 pm on the 27th to 6:00 pm on the 28th is the greatest 24 hour snowfall ever recorded in September.  This was the first snow of the season.  The snow was intermittent through the 26th…but continuous from early afternoon on the 27th to around midnight on the 28th…except for a period of rain during the afternoon of the 28th which contributed to a loss of depth on the ground.  The greatest snow depth on the ground downtown was 13 inches with 8 inches at Denver municipal airport.  There were no high winds with the storm and traffic was interrupted for only a short period.  The storm produced property damage estimated at 7 million dollars.  With trees and shrubs in full foliage…the leaves caught and held the heavy water-laden snow…until the branches snapped from the weight.  More than 3000 workmen were called to remove the debris and snow from the city.  The city firemen who were off duty…as well as all the reserves… Were asked to report to their stations.  All schools in the city remained open…but attendance was only 50 percent of normal.  Grade school students were sent home at noon on the 28th.  The early storm caught stockmen with many cattle still in higher ranges.  Warm weather followed the snow…which had all melted by the end of the month…except for a few inches in sheltered places.

27

In 1877…smoke from heavy forest fires in the mountains spread over the city on upper wind currents.

In 1935…the first snow of the season was 2.8 inches in downtown Denver.  The low temperature dipped to 31 degrees for the first freeze of the season.

27-28

In 1984…heavy snow fell over the plains and foothills. Snowfall amounts ranged from 2 to 5 inches on the plains with up to a foot at higher elevations in the foothills. The main problem caused by the storm was thousands of power outages caused by snow-laden tree limbs snapping and falling onto power lines.  Over 15 thousand homes lost power in metro Denver.  Some cars were damaged by falling trees and limbs.  The snow also caused some flight delays at Stapleton International Airport where 5.1 inches of snow fell and northeast winds gusted to 29 mph.  Maximum snow depth on the ground was 3 inches due to melting.  The high temperature of only 34 degrees on the 28th was a record low maximum for the date and equaled the all-time record for the month at that time.

28

In 1877…heavy dense smoke from mountain forest fires spread over the city.  The smoke was so dense that it obscured the sun at times.

In 1921…post-frontal northeast winds were sustained to 44 mph.

In 1953…a pacific cold front produced a west wind gust to 59 mph at Stapleton Airport where the visibility was briefly reduced to 3/4 miles in blowing dust.  Strong winds were also widespread over Boulder during the afternoon.

In 1960…strong…gusty winds tore the roof from 6 units of a motel on west Colfax Avenue in Denver.  The roofing sailed over the building and crashed down on a truck…wrecking it. The strong winds were the result of an apparent microburst.

In 1999…snow fell in the foothills west of metro Denver and over the plains.  Snowfall totals included 7 inches at conifer.  At the site of the former Stapleton International Airport…3.1 inches of snow were measured.  This was the first snow of the season.  The heavy wet snow snapped branches from fully leafed trees…downing power lines and causing scattered outages.

In 2004…severe thunderstorms produced hail to 3/4 inch in diameter in Littleton and in Douglas County 14 miles northwest of Castle Rock.

In 2012…a weak tornado (EF-0) tornado touched down near Strasburg. No damage was reported.

Continue reading September 26 to October 2: This week in Denver weather history

September 19 to September 25: This week in Denver weather history

This Week in Denver Weather History

This time of year many folks would consider “snow” a bad four-letter word but living in the Mile High City we can’t rule it out even with it technically still being summer.  In fact, it was only 15 short years ago that we received a significant snowstorm that brought up to 8 inches of snow in the metro area and caused millions of dollars in damage.

From the National Weather Service:

15-19

In 1906…rain on 5 consecutive days totaled 1.61 inches. A thunderstorm occurred on the 17th.  High temperatures ranged from 48 degrees on the 16th to 65 degrees on the 15th.  Low temperatures were in the lower to mid 40’s.

16-19

In 1971…a record breaking early fall snow storm caused extensive damage to trees and utility lines.  The heavy wet snow occurred with little wind…but caused record breaking cold temperatures for so early in the season.  Snowfall totaled 15.6 inches at Stapleton International Airport with most of the snowfall…12.0 inches…occurring on the 17th.  This was the heaviest first snow of the season. The maximum snow depth on the ground was 13 inches. Record low temperatures were set on three consecutive days: 31 degrees on the 17th…23 degrees on the 18th…and 20 degrees on the 19th…which was also a new all-time record minimum for the month at that time.  Record low maximum temperatures were set on 4 consecutive days:  48 degrees on the 16th…35 degrees on the 17th…40 degrees on the 18th… And 42 degrees on the 19th.

18-19

In 1955…heavy rains caused flash flooding across portions of metro Denver.  Rainfall totaled 1.71 inches at Stapleton Airport.

19

In 1955…hail stones to 2 1/2 inches in diameter were reported north of Denver.  The large stones broke many automobile windshields.

In 1963…hail to 3/4 inch in diameter fell in Westminster.

In 1983…an unusually strong cold front roared through metro Denver during the afternoon hours.  At Stapleton International Airport…the temperature dropped 51 degrees… From a sunny 86 degrees to a snowy 35 degrees…in just 7 hours.  Strong winds and a wall of blowing dust followed the front.  Northeast winds gusting to 36 mph briefly reduced the surface visibility to 1 mile in blowing dust at Stapleton International Airport where only a trace of snow fell later.

In 1996…high winds gusting to 84 mph were measured at Golden Gate Canyon in the foothills west of Denver. West winds gusted to only 25 mph at Denver International Airport.

20

In 1921…an apparent Bora produced northwest winds sustained to 44 mph with gusts to 64 mph.

In 1955…hail stones 1/2 to 3/4 inch in diameter were reported across parts of the city of Denver.

In 1992…weather observers at Buckley Air National Guard base sighted two tornados southeast of the base.  The tornados were short-lived and caused no injuries or damage.

20-21 in 1963…heavy rain and hail caused local flooding in southeast Denver.  Thunderstorm rainfall was only 0.60 inch at Stapleton Airport on the 20th.

In 1983…the cold front on the 19th brought an unusually cold air mass into metro Denver for so early in the season.  The temperature dipped to a daily record minimum of 28 degrees on both days.

In 1995…a vigorous late summer storm brought the season’s first heavy snow to portions of metro Denver.  Millions of trees were damaged and power lines downed as 4 to 8 inches of heavy wet snow settled on fully leafed trees in the Boulder and Denver areas.  Branches snapped and trees split under the weight of heavy snow…downing power lines. Firefighters responded to numerous transformer fires. Around 100 thousand people were left without electricity in Boulder and Denver areas alone.  It took over a week to fully restore power to some areas.  Insurance claims were estimated to be around 6 million dollars to homes in metro Denver and about 500 thousand dollars in damage to automobiles.  It was estimated that about 80 percent of 125 million dollars worth of city owned trees in Denver were damaged.  Snowfall totaled 7.4 inches at the site of the former Stapleton International Airport where the greatest depth of snow on the ground was only 4 inches due to melting.  Temperature records were set on the 21st when the thermometer dipped to a record low reading of 27 degrees and climbed to a high of only 36 degrees… Setting a record low maximum for the date.  North winds gusted to 29 mph at Denver International Airport on the 20th.

Continue reading September 19 to September 25: This week in Denver weather history

September 12 to September 18: This week in Denver weather history

This Week in Denver Weather History

Normally one doesn’t associate tornadoes with September weather in Denver but they can and do happen as we see in our look back in Denver weather history for the week.  We have a couple of occasions of twisters and of a funnel cloud.  Other severe weather like hail, damaging wind and flooding rains have also occurred.   Oh, and should we mention the dreaded “S” word – snow?

5-13

In 2010…the Fourmile Canyon Wildfire…northwest of Boulder… broke out on the morning of the 5th. It originated from an unattended fire pit at a local residence. The wildfire quickly consumed 5 1/2 square miles or 3500 acres the first day…and forced the evacuation of over three thousand residents. Erratic 45-mph gusts sent the fire in two directions at times. Very dry weather conditions preceded the fire. The combination of strong winds…low relative humidities and dry fuels allowed the wildfire spread rapidly through the steep…heavily forested terrain. The flames were reportedly 20 to 50 feet in length. Towns within the burn area included Salina…Wallstreet and Gold Hill. The dry conditions coupled with gusty winds ranging from 45 to 64 mph persisted for several more days. Fire managers used as many as 700 firefighters and support personnel from 35 agencies and seven air tankers to battle the wildfire. A total of 6181 square acres or approximately 10 square miles were burned. The Fourmile Canyon Wildfire was the most destructive fire in Colorado history in terms of the damage to personal property. It destroyed 171 homes with an estimated cost of 217 million dollars.

11-16

In 2013…a deep southerly flow over Colorado… Ahead of a nearly stationary low pressure system over the great basin… Pumped copious amounts of monsoonal moisture into the area. In addition…a weak stationary front stretched along the Front Range foothills and Palmer Divide.  This resulted in a prolonged period of moderate to heavy rain across the Front Range foothills…Palmer Divide…urban corridor. By the 14th…storm totals ranged from 6 to 18 inches… Highest in the foothills of Boulder County. The headwaters then moved down the South Platte River and caused widespread flooding with record flood stages at several locations as it made its way downstream.  The record high flood stages resulted in widespread flooding along the South Platte River basin. The flood damage encompassed 4500 square miles of the Front Range…left 7 dead… Forced thousands to evacuate…and destroyed thousands of homes and farms. Record amounts of rainfall generated flash floods that tore up roads and lines of communication… Leaving many stranded. Nearly 19000 homes were damaged… And over 1500 destroyed. Colorado department of transportation estimated at least 30 state highway bridges were destroyed and an additional 20 seriously damaged. Preliminary assessments of the state`s infrastructure showed damage of $40 million to roads and $112 million to bridges. Repair costs for state and county roads ran into the hundreds of millions of dollars. Miles of freight and passenger rail lines were washed out or submerged… Including a section servicing Amtrak`s iconic California Zephyr. The town of Lyons was isolated by the flooding of St. Vrain creek…and several earth dams along the Front Range burst or were over-topped. Floodwaters swept through Estes Park; damaged hundreds of buildings and destroyed large sections of U.S. 34 from Loveland and U.S. 36 from Lyons to Boulder. U.S. 34 suffered the most damage… With 85 percent of its roadway and bridges destroyed. In Weld County…about nearly two thousand gas wells were damaged and had to be closed off as the floodwaters inundated entire communities. Sewage treatment plants and other utilities were knocked out in a number of towns. Governor Hickenlooper declared a disaster emergency on September 13th…in 11 counties across northeast Colorado including:  Adams…Arapahoe…Broomfield…Boulder…Denver…  Jefferson…Larimer…Logan…Morgan… Washington and Weld. By the 15th…federal emergency declarations covered those counties as well as Clear Creek County. Projected losses from the flooding statewide was nearly two billion dollars in property damage…according to Eqecat… A catastrophe modeling firm.  The damage was most severe in and around Lyons and Boulder.  More than 11 thousand people were evacuated…reportedly the largest since Hurricane Katrina. President Obama declared a state of emergency for Boulder and Larimer counties.  An additional 10 counties were added on the 16th and included: Adams… Arapahoe…Broomfield…Clear Creek…Denver…Jefferson…  Morgan…Logan… Washington and Weld counties. The president also declared a major disaster specifically for Boulder County.  There were six fatalities directly attributed to flash flooding. Two 19-yr old teenagers died on the 11th…after they were swept away by floodwaters after abandoning their car on Lindon Drive in Boulder. In Jamestown…a 72-yr old man was killed when the building he was in collapsed. An 80-yr old Lyons resident died in the early morning hours of the 12th…when his truck was swept into the St. Vrain River near his home. Later on the 12th…a 79-yr old Larimer County resident was killed when she was swept away while trying to climb to safety from her home in Cedar Point. A 61-yr old cedar point resident died when her home was swept down the Big Thompson River by the floodwaters. An 80-yr old Idaho Springs resident drowned in Clear Creek when the embankment he was standing on collapsed. In Boulder…some of the monthly records broken included: one-day all-time record: 9.08 inches which shattered the previous wettest day of 4.8 inches set on July 31… 1919; one-month record of 18.16 inches…which broke the previous all-time monthly record of 9.59 inches set in May of 1995; wettest September on record which broke the previous record of 5.5 inches set in September of 1940; one-year record of 34.15 inches broke the previous wettest year of 29.93 inches set in 1995. At Denver International Airport…the total precipitation for the month of September was 5.61 inches…which was 4.65 inches above the normal of 0.96 inches. This is the most precipitation ever recorded in Denver for the month of September. Daily precipitation records included 1.11 inches on the 12th and 2.01 inches on the 14th.

11-12

In 1974…post-frontal rain changed to snow overnight for the first snow of the season.  Snowfall totaled only 1.8 inches at Stapleton International Airport where north winds gusted to 40 mph on the 11th.  High temperature of only 46 degrees on the 12th set a new record low maximum for the date.

12

In 1887…west winds to 42 mph were recorded in the city.

In 1952…a thunderstorm outflow produced strong southeast winds gusting to 52 mph.  Surface visibility at Stapleton Airport was briefly reduced to 2 miles in blowing dust.

In 1963…a nearly stationary…white tornado near Bennett was sighted from Denver.  No damage was reported.

In 1989…an early snowfall and the first of the season brought 2 to 3 inches of slush to metro Denver.  More snow whitened the foothills west of Denver where 6 inches were measured at Evergreen.  The snow fell on leaf laden trees… And sagging branches onto power lines caused outages.  Much of Denver’s snow fell during the evening rush hour…creating traffic chaos.  Snowfall totaled 2.3 inches at Stapleton International Airport where the maximum snow depth on the ground was only 1 inch due to melting.

In 1994…thunderstorm microburst winds gusted to 67 mph in Boulder.  No damage was reported.

In 2002…a severe thunderstorm produced hail as large as 1 inch in diameter near Castle Rock.

13

In 1899…west winds were sustained to 43 mph with gusts to 46 mph.

In 1928…northwest winds were sustained to 41 mph with gusts to 45 mph.

In 1937…an apparent dry microburst produced brief north winds sustained to 31 mph with gusts to 41 mph.  There was a trace of rain.

In 1982…torrential rains drenched both the foothills and plains from Denver north.  While the heaviest rain occurred north of Denver…just east of Denver 2 1/3 inches of rain fell in 5 hours along with hail that caused minor damage to a few airplanes.  Thunderstorm rainfall totaled 0.83 inch at Stapleton International Airport.

In 1993…an upper level system combined with a cold and moist upslope flow to bring the heaviest snowfall to metro Denver for so early in the season.  Snowfall from the storm totaled 5.4 inches at Stapleton International Airport; however…most of the snow melted as it fell leaving a maximum of one inch on the ground at any one time.  North winds gusted to 21 mph at Stapleton International Airport where a record low temperature of 33 degrees for the date was observed.

In 2002…Friday the 13th proved to be bad luck for several motorists when heavy thunderstorm rainfall caused flooding on I-25 in central Denver.  Water rose several feet under the Logan Street overpass…inundating several vehicles. Some motorists were rescued…while others simply waited atop their cars for the flood water to recede.  The highway had to be closed in both directions for about 3 hours.  The flooding was exacerbated by poor drainage due to the construction along the highway.  A 12-foot drainage pipe had not yet been installed beneath the underpass.  The deluge also flooded several businesses along Broadway.

Continue reading September 12 to September 18: This week in Denver weather history

Denver crushes the record high temperature for September 10

Record High Temperature

We knew the record would be broken, it was only a question of by how much and the results are in.

As measured at Denver International Airport, the high temperature in the Mile High City topped out at 99 degrees. These destroys the previous record high for September 10 of 93 degrees set in 2018.

Here in Thornton we were close to Denver’s mark but “only” hit 98 degrees.

Denver sets record high temperature for September 9

Record High Temperature

Mother Nature just delivered another reminder that our long, hot summer isn’t over yet.

Denver, as measured at Denver International Airport, reached a high temperature of 96 degrees today. This tops the previous record high temperature for September 9 of 94 degrees set in 1994.

Here in Thornton, we were a bit “cooler” with a 95 degree reading at 1:49pm.

More heat is yet to come. Tomorrow may see highs a couple of degrees warmer than today. The record high for September 10 is 93 degrees set in 2018 and previous years so it is quite likely that record will fall as well.

More in the extended forecast here.

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