Category Archives: Weather History

News and related items pertaining to national, Colorado, Denver and Thornton weather.

Ranking the top 10 Colorado weather events of the past 10 years

The March 2003 blizzard that buried Thornton in snow was ranked as the top weather event of the past 10 years. (ThorntonWeather.com)
The March 2003 blizzard that buried Thornton in snow was ranked as the top weather event of the past 10 years. (ThorntonWeather.com)

There is a lot that can be said about the weather in Colorado but ‘boring’ is not usually a term associated with it.  Anyone who has lived in the Centennial State for very long quickly experiences a weather-related event that will give them memories for a lifetime. 

From major snowstorms and blizzards to tornadoes, wildfires, scorching heat and damaging hail storms Colorado weather can and does bring it all to the table.  The Denver office of the National Weather Service has released a list of what local meteorologists rank as the top 10 weather events of the past 10 years.

For some it may be a blizzard that buried the Mile High City in a heavy blanket of snow and brought everything to a standstill.  Others will remember the heavy smoke from fires burning in the mountains destroying hundreds of thousands of acres.  The tragedy tornadoes bring to Colorado in terms of destruction and loss of life may be what others remember.

Over the past 10 years many memorable weather events have occurred that fully display the sheer variety of weather Colorado receives.  A team of meteorologists serving Colorado analyzed these events and ranked them based on meteorological intensity and their human and economic impact.

Continue reading Ranking the top 10 Colorado weather events of the past 10 years

December 26 to January 1 – This week in Denver weather history

December 26 to January 1 - This week in Denver weather history
December 26 to January 1 - This week in Denver weather history

Winter wind in Colorado can be quite nasty oftentimes reaching damaging levels and we see numerous occurrences of that in our look back at this week in Denver weather history.  Also notable are storm system just a few years ago in 2006 and 2007 that dumped a good amount of snow on the Denver area.

25-26

In 1904…after a warm Christmas Day with a high temperature of 50 degrees…a late day cold front plunged temperatures to a low of 7 degrees…produced northeast winds sustained to 40 mph with gusts to 54 mph…and produced 5.2 inches of snow overnight for a late white Christmas.  The maximum temperature on the 26th was only 16 degrees.

25-31

In 1980…temperatures were unusually warm during the week between Christmas and New Year’s.  High temperatures for the week ranged from the mid-50’s to the mid-70’s.  Four temperature records were set.  Record highs occurred on the 26th with 68 degrees…the 27th with 75 degrees…and the 30th with 71 degrees.  A record high minimum temperature of 41 degrees occurred on the 27th.

26 

In 1877…heavy snow fell during the early morning and totaled nearly 6 inches.  Precipitation from melted snow was 0.58 inch.  After the snowfall…a number of sleighs were seen on the city streets.
 
In 1879…after a morning low of 4 degrees below zero… The temperature climbed to a high of 57 degrees in the city.
 
In 1907…west winds were sustained to 40 mph.  The Chinook winds warmed the temperature to a high of 62 degrees.
 
In 1949…west winds gusted to 50 mph at Stapleton Airport.
 
In 1998…intense…but localized…downslope high winds developed near Wondervu in the foothills southwest of Boulder.  Winds frequently gusted to 100 mph with a highest reported wind gust to 104 mph.  West winds gusted to only 43 mph at Denver International Airport.

Continue reading December 26 to January 1 – This week in Denver weather history

December 19 to December 25 – This week in Denver weather history

December 19 to December 25 - This week in Denver weather history.
December 19 to December 25 - This week in Denver weather history.

Cold and snow dominate our look at the week leading up to the Christmas holiday.  Certainly the infamous Christmas Eve Blizzard of 1982 is the one event that most long-time resident will remember as it was truly one for the history books.  Also notable was a cold front that moved through in 1988 that dropped temperatures well below zero and was responsible for at least five deaths.

17-24

In 1924…a prolonged cold spell occurred after mild temperatures during the first half of the month.  Most low temperatures dipped below zero with the coldest reading of 15 degrees below zero occurring on the 24th. The high temperature of only 5 degrees on the 18th was a record low maximum for the date.

18-24

In 1998…a vigorous cold front with north winds gusting as high as 38 mph at Denver International Airport on the 18th dropped temperatures from a high of 51 degrees to a low of just 6 degrees before midnight.  The arctic air mass that settled over metro Denver produced intermittent light snow and a week-long protracted cold spell that caused low temperatures to plunge well below zero for 6 consecutive nights.  The coldest temperature was 19 degrees below zero on the morning of the 22nd.  High temperatures climbed only into the single digits on 4 consecutive days…from the 19th through the 22nd.  At least 15 people…mostly homeless… Were treated for hypothermia at area hospitals.  The bitter cold weather was responsible…either directly or indirectly… For at least 5 fatalities.  Three of the victims died directly from exposure.  The cold weather also caused intermittent power outages.  Following the cold snap… Thawing water pipes cracked and burst in several homes and businesses…causing extensive damage.  Only one temperature record was set.  The high temperature of only 7 degrees on the 19th set a record low maximum for the date.

19

In 1913…post-frontal heavy snowfall totaled 8.5 inches over downtown Denver.  North winds were sustained to only 16 mph.
 
In 1994…an intense pacific storm system and associated cold front moved across Colorado early in the day.  Strong downslope winds buffeted the Front Range eastern foothills. The highest wind gust recorded was 92 mph at Rocky Flats in northern Jefferson County.  Most of the wind gusts during the day ranged from 63 to 86 mph with lighter gusts of 40 to 58 mph on the northeast plains.  The strong winds downed power lines and poles in south Lakewood…causing power outages to 2400 homes.  Other small power outages and surges occurred across metro Denver.  Northwest winds gusted to 43 mph at Stapleton International Airport.

Continue reading December 19 to December 25 – This week in Denver weather history

December 12 to December 18 – This week in Denver weather history

December 12 to December 18 - This week in Denver weather history
December 12 to December 18 - This week in Denver weather history.

We all know weather can be dangerous but usually we don’t associate that with winter weather conditions.  However, our look in Denver weather history for this week shows that the common winter conditions of wind and cold can not only cause injure, it can lead to death. 

2-17

In 1939…more than 2 weeks of unseasonably warm weather made the month the 3rd warmest on record.  Seven daily temperature records were set…including the all time record high temperature for the month of 79 degrees on the 5th.  Daytime highs were balmy with 14 days in the 60’s and 70’s.  Low temperatures dipped to freezing or below on only 5 days.  The period was dry with only a trace of snow on the 12th.

3-15

In 1972…a protracted cold spell held an icy grip on metro Denver when maximum temperatures never reached above freezing for 10 consecutive days from the 3rd through the 12th and minimum temperatures dipped below zero on eleven consecutive days from the 5th through the 15th. Daily low temperature records were set with 15 degrees below zero on the 5th…17 degrees below zero on the 6th… And 18 degrees below zero on the 10th.  Daily record low maximum readings were set with 3 degrees on the 6th and 6 degrees on the 9th.  The very cold temperatures were caused by 3 to 5 inches of snow cover and a Canadian air mass.

8-12

In 1932…the second longest sub-zero period on record in Denver occurred.  The temperature fell below zero shortly after 1:00 pm on the 8th and remained below zero for 92 hours until 9:00 am on the 12th.  The lowest temperature recorded during this period was 13 degrees below zero on both the 9th and 11th.  That temperature on the 11th was a record low for the date.  High temperatures of 4 on the 8th…5 below zero on the 9th…1 below zero on the 10th… And 6 below zero on the 11th were record low maximum temperatures for those dates.  Light north winds at 5 to 10 mph were accompanied by occasional light snow…which totaled only 2.2 inches.

9-13

In 1961…cold arctic air produced a protracted cold period. The temperature plunged to 16 degrees below zero on the 10th…establishing a new record for the date and the coldest reading since 25 degrees below zero on February 1… 1951.  Low temperatures dipped below zero on 5 consecutive days with 9 degrees below zero on the 9th…16 below on the 10th…10 below on the 11th…and 12 below on both the 12th and 13th.  High temperatures reached only 3 degrees on the 10th and 6 degrees on the 11th.

11-12

In 1903…a sharp cold front on the 11th plunged temperatures from a high of 59 degrees to a low of 15 degrees…produced northeast winds sustained to 42 mph along with gusts as high as 60 mph…and produced 1.3 inches of snow overnight. The high temperature on the 12th was only 25 degrees.
 
In 1968…strong winds buffeted the eastern foothills and plains and caused light…but widespread property damage. Wind gusts of 50 to 75 mph were reported.  West winds gusted to 52 mph at Stapleton International Airport.

Continue reading December 12 to December 18 – This week in Denver weather history

The weather and the ‘date which will live in infamy’

December 7, 1941.  From left, the USS USS West Virginia, USS Tennessee, both damaged and USS Arizona, sunk.  The weather played a key part in the attack on Pearl Harbor.
December 7, 1941. From left, the USS USS West Virginia, USS Tennessee, both damaged and USS Arizona, sunk. The weather played a key part in the attack on Pearl Harbor.

The weather that morning was beautiful over Pearl Harbor as one might expect in paradise.  The USS Tennessee reported winds at 11 to 16 miles an hour and slight wind ripples on the water of the bay.  The USS Oklahoma reported clear skies with “intermittent moving fleecy clouds.”  Little did the men making those weather reports know that hell was about to rain down on them.

69 years ago today, the United States was forced into World War II with the brutal surprise attack on Pearl Harbor.  Over 2,300 servicemen lost their lives on that fateful day, a “date which will live in infamy.” Relatively unknown in the stories of that fateful day is how the weather played a key and prominent role.

On December 4th, a Japanese intelligence officer at their embassy in Washington D.C. was listening to Radio Tokyo as he had been for the last two weeks.  The weather report:  “Higashi no kaze ame”, or “east wind, rain.”  That seemingly innocent phrase was in actuality code to Japanese diplomats to destroy all of their cryptographic equipment, books and top secret documents as an attack was imminent.  A weather report sounded the alarm that war was coming.
 
On Oahu, December and January are actually the cloudiest months and this was a concern for the Japanese in the planning of their attack.  Timing was of the essence as winter in the Pacific can be brutal and if they were forced to wait till late December, success would be in doubt.  The clouds would be good for hiding the planes on their approach to the islands but if they couldn’t see their targets, the attack could not be successful.

220 miles north of Oahu and heading east into a steady wind, the Japanese fleet launched its planes at 6:10am.  The wind provided the extra lift for the bomb-laden planes and low clouds at 5,000 feet helped to provide cover for the fleet and its planes.  The question remained however – would there be clouds over the target?

As the planes headed toward Pearl, U.S. code breakers intercepted a message from Tokyo to Japanese diplomats telling them to break off talks with the United States.  At 7:33am, Army Chief of Staff, General George C. Marshall, believed this could be the harbinger of an attack and he sends a warning to Lt. Gen. Walter C. Short, commander of U.S. Army forces in Hawaii.  Atmospheric static however prevents the message from being sent by radio and Marshall’s message is sent via commercial telegraph instead. Short’s headquarters receives the message at 11:45am and he did not see it until 3:00pm – more than eight hours after the attack had started.

Flying between 9,000 and 14,000 feet, the clouds provided the cover that the Japanese planes needed.  Using a Honolulu radio station to guide them, the planes neared the north coast at 7:30am and heard the radio announcer report, “clouds, mostly over the mountains.  Visibility good.”  That is exactly what they wanted to hear.  Their approach over the mountains of the island was concealed by the clouds and as they neared Pearl Harbor, those clear skies reported by the USS Oklahoma and Tennessee provided the bombers the visibility they needed to hit their targets.  At 7:55am, metal rain began to fall on our soldiers, sailors and airmen.

Our nation was forever changed that day and as is often the case, the weather played a key role in this moment in history.  After the attack, Japanese Admiral Isoroku Yamamoto said, “We have awakened a sleeping giant and have instilled in him a terrible resolve.”  Indeed that was the case but the price was heavy as nearly 300,000 United States service members would lose their lives in the years to come.

Dallas City Hall, Veterans Day, November 11, 2004. Houston James, a survivor of the attack on Pearl Harbor, hugs Marine Staff Sergeant Mark Graunke Jr., a member of an explosive disposal team who lost his left hand, one leg and an eye in Iraq.
Dallas City Hall, Veterans Day, November 11, 2004. Houston James, a survivor of the attack on Pearl Harbor, hugs Marine Staff Sergeant Mark Graunke Jr., a member of an explosive disposal team who lost his left hand, one leg and an eye in Iraq.

On  personal note, I ask all of our readers to take the time today to acknowledge and remember not only those that paid the ultimate sacrifice on December 7, 1941 and in the following years, but also remember that more than 16 million men and women served in the armed forces during World War II.  Of those, a mere 2.3 million are still with us today and 1,000 World War II veterans die each and every day.  As we mourn their passing, we should also remember that which they stood for – honor, sacrifice, courage, God and country.  There had never been – and there never will be – a generation like theirs.  I thank them for their service and hope they may have the peace in heaven that they did not see while on earth.  God bless you all. 

For more information:  Please help Thornton build a memorial to honor not only World War II veterans but all veterans from all branches of service and all wars.  The owner and operator of ThorntonWeather.com is a significant contributor to the project and asks that our visitors consider donating to the project.  Please visit the Thornton Veterans Memorial website for more information.

December 4 to December 11 – This week in Denver weather history

December 4 to December 11 - This week in Denver weather history
December 4 to December 11 - This week in Denver weather history

While Denver still waits for its first significant snowfall of the season, in years past it has been much easier to come by.  Looking back we see one five day storm that dumped snow that was measured in feet and many other smaller ones that were significant in their own right.

1-5

In 1913…the 1st marked the start of the heaviest 5-day total snowfall in the city’s history.  During this period snowfall totaled 45.7 inches.  Starting on the 1st…snow fell intermittently for 3 days and accumulated a little over 8 inches.  On the 4th and 5th…an additional 37.4 inches of snow fell.  At Georgetown in the foothills west of Denver even more snow fell…86 inches over the 5 days with the most…63 inches…on the 4th.  In Colorado…snowfall was heavy along the eastern slopes of the mountains from the Palmer Divide north.  High winds during the storm caused heavy drifting…which blocked all transportation.  Snow cover of an inch or more from the storm persisted for 60 consecutive days from the 1st through January 29…1914. Additional snowfall in December and January prolonged the number of days.  This is the third longest period of snow cover on record in the city.

2-17 

In 1939…more than 2 weeks of unseasonably warm weather made the month the 3rd warmest on record.  Seven daily temperature records were set…including the all time record high temperature for the month of 79 degrees on the 5th.  Daytime highs were balmy with 14 days in the 60’s and 70’s.  Low temperatures dipped to freezing or below on only 5 days.  The period was dry with only a trace of snow on the 12th.

3-15 

In 1972…a protracted cold spell held an icy grip on metro Denver when maximum temperatures never reached above freezing for 10 consecutive days from the 3rd through the 12th and minimum temperatures dipped below zero on eleven consecutive days from the 5th through the 15th. Daily low temperature records were set with 15 degrees below zero on the 5th…17 degrees below zero on the 6th… And 18 degrees below zero on the 10th.  Daily record low maximum readings were set with 3 degrees on the 6th and 6 degrees on the 9th.  The very cold temperatures were caused by 3 to 5 inches of snow cover and a Canadian air mass.

Continue reading December 4 to December 11 – This week in Denver weather history

November 27 to December 4 – This week in Denver weather history

November 27 to December 4 - This week in Denver weather history
November 27 to December 4 - This week in Denver weather history

Cold, snow and wind are part of life on the Great Plains and we see all of those events have struck in abundance during this week in Denver weather history.  Many of the wind events were damaging and the snow accumulations significant.

From the National Weather Service:

25-28

In 1952…the average coldest 4-day period in November in the previous 81 years of record occurred.  Maximum temperatures of 19…15…21…and 25 degrees were recorded.  Minimum temperatures were below zero each day with readings of 7 below…6 below…5 below…and 6 below.

25-29

In 1985…dense fog with visibilities as low as 1/8 mile occurred on five consecutive days at Stapleton International Airport.  The fog was at times accompanied by light snow… Light freezing drizzle…or ice crystals.  Fog occurred all day on both the 26th and 29th.

28

In 1884…a windstorm during the afternoon produced northwest sustained winds to 46 mph.  Two wooden slats were blown out of the weather instrument shelter…and nearly all of the slats on the north and west sides were loosened.
 
In 1898…northwest winds were sustained to 50 mph with gusts as high as 80 mph.
 
In 1902…northwest winds were sustained to 40 mph with gusts to 48 mph.  The strong apparent Bora winds warmed the temperature to a high of only 40 degrees.
 
In 1904…northwest winds sustained to 44 mph with gusts to 58 mph warmed the temperature to a high of 58 degrees.
 
In 1927…strong west winds occurred in Boulder…causing widespread minor damage.  A wind gust to 65 mph was recorded at Valmont east of Boulder.  The west winds possibly produced a cyclonic twist.
 
In 1928…heavy snowfall totaled 7.0 inches over downtown Denver.
 
In 1957…a vigorous cold front produced north-northeast wind gusts to 54 mph at Stapleton Airport.  Light snow following the front totaled only 0.2 inch.
 
In 1970…strong Chinook winds reached 77 mph in downtown Boulder.
 
In 1978…wind gusts 60 to 90 mph were reported in and near the foothills.
 
In 1984…high winds of 60 to 80 mph occurred along the Front Range eastern foothills.  In Boulder…the high winds blew the roof off a service station.  Several trees were felled… Damaging some cars.  An elderly woman was injured when she was knocked down by a wind gust and blown 20 feet into some bushes.  Northwest winds gusted to 36 mph at Stapleton International Airport.
 
In 1994…winds gusted to 72 mph in Boulder.  No damage was reported.  Northwest winds gusted to 35 mph at Stapleton International Airport.

Continue reading November 27 to December 4 – This week in Denver weather history

November 21 to November 27 – This week in Denver weather history

November 21 to November 27 - This week in Denver weather history
November 21 to November 27 - This week in Denver weather history

Weather is a big part of the holidays.  With many people hitting the road to visit friends and family the weather can make or break those holiday plans.  Our look back at this week in Denver weather history shows a number of Thanksgivings when the weather put a damper on travel plans.

19-21

In 1979…a heavy snowstorm buried most of Colorado under at least a foot of snow.  Snowfall at Stapleton International Airport totaled 17.7 inches…the greatest snow depth since 1946.  Winds to 60 mph produced 5-foot drifts paralyzing the city as temperatures hovered in the 20’s.  While small airports closed…Stapleton remained open…but with long delays that snarled Thanksgiving holiday traffic.  Schools and businesses closed and postal deliveries were delayed. Almost all major highways leading out of Denver were closed to traffic for periods of time on the 20th and 21st.  Most of the snow…13.5 inches…fell on the 20th.  At Stapleton International Airport…north winds gusted to 35 mph on the 20th and to 38 mph on the 21st.

20-21

In 1898…snowfall totaled 4.0 inches in downtown Denver. Northeast winds were sustained to 48 mph with gusts as high as 60 mph behind an apparent cold front on the 20th… When temperatures plunged from a high of 66 degrees to a low of 9 degrees.  On the 21st the high was only 24 degrees and the low was 2 degrees.
 
In 1970…a wind gust to 94 mph was recorded at gold hill in the foothills west of Boulder.  Strong winds also swept across metro Denver.  Wind gusts reached 59 mph in downtown Boulder…while at Stapleton International Airport west- northwest winds gusted to 43 mph on the 21st.  Damage was minor.
 
In 1992…a large Canadian air mass moved into the state at the same time an upper level storm system approached from the west.  The combination of cold air at the surface and very moist air aloft produced heavy snow across the entire state.  Snowfall totaled 6.3 inches at Stapleton International Airport…where north winds gusted to 23 mph on the 20th.  Snow was heavier in the foothills…with 14 inches at Wondervu…13 inches at Aspen Springs…Conifer… Boulder…and Gross Reservoir…8 inches at Rollinsville… And 10 inches at Golden Gate Canyon and Morrison.
 
In 2007…a storm system brought moderate to heavy snowfall to portions of the urban corridor.  Storm totals included: 7 inches…3 miles south-southeast of Fort Collins…with 6 inches in Boulder and at Horsetooth inlet bay.  Elsewhere… Storm totals ranged from 2 to 5 inches.  Snowfall totaled 2.0 inches at the site of the former Stapleton International Airport.

Continue reading November 21 to November 27 – This week in Denver weather history

November 14 to November 20 – This week in Denver weather history

November 14 to November 20 - This week in Denver weather history
November 14 to November 20 - This week in Denver weather history

Henry Fenton is probably not a name many folks are familiar with however he will forever be engrained in the Denver weather history books.  It was 139 years ago this week that Fenton made the first official Denver weather observations.

From the National Weather Service:

11-14

In 1970…heavy snowfall totaled 7.2 inches at Stapleton International Airport where northeast winds gusted to 22 mph on the 12th and 14th.  Most of the snow… 4.2 inches…fell on the 12th.

12-15

In 1909…light snowfall totaled 6.7 inches in downtown Denver over the 4 days.  This was the first measurable snowfall of the season.  Northeast winds were sustained to 15 mph on the 12th.

13-14

In 1925…heavy post-frontal snowfall totaled 6.4 inches overnight in downtown Denver.  Northwest winds were sustained to 27 mph with gusts to 29 mph on the 13th.
 
In 1974…northwest winds gusted to 52 mph at Stapleton International Airport…warming the temperature to 60 degrees shortly after midnight on the 13th.  A cold front cooled temperatures into the 20’s by late morning and produced snowfall of 3.7 inches.  The low temperature dipped to 14 degrees on the 14th.
 
In 1993…an upper level low pressure system combined with a weak but moist upslope flow to produce heavy snow across metro Denver.  Snowfall amounts averaged 6 to 8 inches with up to 16 inches in the foothills at the Eldora Ski Area. Snowfall totaled 6.0 inches at Stapleton International Airport where north winds gusted to only 20 mph on the 14th.  Most of the snow fell on the 14th.
 
In 1994…heavy snow developed rapidly along the Front Range urban corridor with the heaviest snow over northwest metro Denver.  Sixteen to 18 inches of snow fell in Boulder… Lafayette…and Louisville.  This was the second heavy snowfall over northwest metro Denver in 10 days.  Eleven to 14 inches of snow were measured from Longmont southward into Aurora.  Snowfall totaled 12.1 inches at Stapleton International Airport where northeast winds gusted to 29 mph on the 13th.  Most of the snow…9.0 inches…fell on the 14th.
 
In 1997…heavy snow fell overnight in portions of Jefferson and Boulder counties.  About 5.5 inches of snow were reported in Boulder…while 4 inches were measured 12 miles southwest of Morrison and 6 miles southwest of Golden. Snowfall totaled only 1.8 inches at the site of the former Stapleton International Airport.  Northeast winds gusted to 26 mph at Denver International Airport.

Continue reading November 14 to November 20 – This week in Denver weather history

October 31 to November 6 – This week in Denver weather history

October 31 to November 6 - This week in Denver weather history
October 31 to November 6 - This week in Denver weather history

Frightening weather does not seem to be in the cards for our Halloween or the immediate future.  That however is not always the case as we look back at this week in Denver weather history.

28-31

In 1929…rain changed to snow on the afternoon of the 28th and continued until midday on the 30th followed by intermittent light snow which continued through the 31st. Snowfall over the four days totaled 16.2 inches in the city.  Most of the snow…8.5 inches…fell on the 29th with 6.1 inches on the 30th.  Temperatures hovered in 20’s during most of the storm.

29-31

In 1889…the first snowfall of the season totaled 14.0 inches over the three days in downtown Denver.  Snowfall was 8.0 inches on the 29th and 5.0 inches on the 31st.  North to northeast winds gusted to 30 mph on the 29th.
 
In 1950…a warm spell resulted in five daily temperature records.  Record highs of 84…80…and 79 degrees occurred on the 29th…30th…and 31st…respectively.  Low temperature of 49 degrees on the 30th was the record high minimum for the date.
 
In 1991…the second surge of cold arctic air in a matter of days plunged metro Denver into the deep freeze.  While low temperatures remained above zero…high temperatures were only in the 20’s.  Three temperature records were set: record lows of 7 degrees on the 30th and 10 degrees on the 31st and a record low maximum of only 21 degrees on the 30th.  Snowfall was light with only 1.9 inches recorded at Stapleton International Airport where east winds gusted to 23 mph.
 
In 2002…snowfall totaled 4.3 inches at the site of the former Stapleton International Airport.  North winds gusted to 32 mph on the 29th behind a cold front…which plunged temperatures well below seasonal normals.  High temperatures of 18 degrees on the 30th and 19 degrees on the 31st were record low maximums for each date.  Low temperatures dipped to 12 degrees on the 30th and 15 degrees on the 31st.

Continue reading October 31 to November 6 – This week in Denver weather history