Category Archives: Colorado Weather

Colorado Weather, Thornton Weather

Thornton begins digging out from early winter storm

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This image from the ThorntonWeather.com webcam was captured at the height of the storm.
This image from the ThorntonWeather.com webcam was captured at the height of the storm.

A two-day storm that saw areas around Denver measuring snow in terms of feet has moved out of the area and onto the plains. The lingering effects of the storm will be felt Friday in terms of slick roads in Denver and blizzard conditions to the east.

The early winter storm, while not entirely unusual, was the first major snow storm of the season and put Coloradoans to the test. Mercifully, the snow never fell at a particularly heavy rate and while it lingered for a long time, it allowed road crews and residents time to stay on top of the snowfall. Most schoolchildren were pleased to have received at least one snow day from the storm and many were the recipients of two unplanned days off.

At Denver International Airport, initial success at holding the storm’s effects at bay on Wednesday began to whither under the white onslaught on Thursday as winds picked up and the storm shifted east. Hundreds of flights were canceled from the airport’s major carriers including United Airlines, Frontier Airlines and Southwest Airlines.

At the height of the storm’s effects, the airport was reduced to two operating runways from the usual six and delays of up to four hours were occurring. All airlines anticipate being able to operate a normal flight schedule today.

How much snow did the Denver area receive? Here are some of the snowfall totals:

Aurora: 16 inches
Boulder: 18.8 inches
Broomfield: 20 inches
Centennial: 17 inches
Coal Creek Canyon: 46 inches
Denver International Airport: 12 inches (as of 6:00am Thursday)
Evergreen: 30 inches
Highlands Ranch: 24.5 inches
Littleton: 28.5 inches
Longmont: 12.4 inches
Parker: 14.5 inches
Thornton: 14.1 inches
Click here for a complete listing of storm reports.

The storm did push Denver into the record books and the ‘top 10 snowiest Octobers’ list. The National Weather Service will publish the official snow total from DIA for yesterday but even without the snow from yesterday, October 2009 makes the list. As of 6:00am on Thursday, DIA had recorded 14.5 inches for the month (12 inches from this storm). That makes it number 7 on the top 10 list for snowiest Octobers on record since 1882. Once today’s measurement is released, it is possible it will climb further.

There's more to this story on the Denver Weather Examiner's site!For the rest of the storm recap, the latest photos and much more, please visit the story on the Denver Weather Examiner.

Colorado Weather, Thornton Weather

Incredible time lapse video – Thornton’s October 2009 snowstorm

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From the evening of October 27, 2009 through October 29, 2009, the Denver metro area was struck by a major, early winter snowstorm. The mountains and foothills to the immediate west of Denver were measuring the snowfall in feet while in the city more than a foot of snow fell in less than 72 hours.  Here in Thornton we recorded 14.1 inches of snow during the event.

This time lapse video below was captured by our east facing webcam. It begins early Tuesday morning (October 27th) and runs through midnight on Thursday, October 29th. As it starts, you can see the first day started out nice enough but by evening the wind was blowing and rain was falling. That soon changed to snow and the snowstorm was in full force for two days.

Colorado Weather, Thornton Weather

Record setting cold may be on the way

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As the Colorado Rockies return home to play game 3 of the National League Divisional Series against the Philadelphia Phillies, the weather could prove to be a tougher opponent than the opposing team. As we forecast early this week, a major blast of Arctic air will be arriving over Colorado tonight and will send thermometers plunging, possibly into record setting territory.

Over the next 48 hours, Denver could break three, very chilly records:

  • The record low temperature for Denver on the 10th of October (Saturday), the day of the game, is 25 degrees. That was set more than 100 years ago in 1905.  Tonight’s / tomorrow morning’s forecast low temperatures are expected to be in the low 20’s.
  • The record low maximum temperature for the 10th is 34 degrees, set in 2005. Tomorrow’s forecast high temperature is expected to be in the mid 30’s.
  • The record low temperature for the 11th of October (Sunday) is 22 degrees set in 1946. Current forecasts put the overnight low Saturday / Sunday morning as possibly hitting down to 17 degrees.

Of the three, it seems pretty likely we will break the first and the third record listed. The second one is a bit up in the air.

There's more to this story on the Denver Weather Examiner's site!For a detailed look at what the weather forecast holds for the Rockies and Phillies, check out our forecast at Examiner.com.

Colorado Weather, Severe Weather, Thornton Weather

Summer 2009 in review – The summer of storms

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This funnel cloud was seen from the Thornton Civic Center (looking north) on June 10th. Image courtesy Lisa Wilson, the City of Thornton.
This funnel cloud was seen from the Thornton Civic Center (looking north) on June 10th. Image courtesy Lisa Wilson, the City of Thornton.

As summer 2009 comes to a close, it is perhaps most fitting that fall arrives with nearly winter-like weather. We ushered in the summer a month early with a record setting high temperature and soon followed that up with a near constant stream of severe weather for weeks. In fact, most of the events during what was a very active summer season actually occurred in the weeks leading up to the official start of summer.

Even though the official start of summer was a month away, May 19th seemed to be an unofficial start as the mercury climbed to 90 degrees that day setting a new record for the date. The very next day in perhaps what was a sign of things to come, a tornado touched down in Mesa County – only the ninth to strike in that county since 1950.

On May 24th, the first of many severe weather days arrived bringing rain totals of more than an inch to some areas of the Front Range and a funnel cloud over Aurora. As the afternoon progressed the severe weather continued and three tornadoes had been reported in the metro area.

After a couple weeks of relative calm, the severe weather once again appeared and on June 7th funnel clouds and tornadoes seemed to be appearing everywhere. From the north metro area in Broomfield to Aurora, most of the Front Range had some sort of direct severe weather threat. Most notably,the Southlands Shopping Center was struck by an EF1 tornado where extensive damage to the mall occurred.

There's more to this story on the Denver Weather Examiner's site!All of that was only a start to what was a very eventful summer for Thornton and Denver!  Read the rest of this story on Examiner.com!

Colorado Weather, National Weather

Western wildfires send smoke over Colorado – Health warning issued

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The view of the Rocky Mountains from Denver is obscured by haze caused by smoke from wildfires burning across the western United States.
The view of the Rocky Mountains from Denver is obscured by haze caused by smoke from wildfires burning across the western United States.

Update, 5:30pm – The Colorado Department of Public Health and Environment has issued a smoke health advisory for northwest and north-central Colorado.  The department warns that residents may wish to limit outside activity, particularly those with heart disease, respiratory illnesses, the very young, and the elderly. 

Read the advisory in its entirety at the bottom of this story.

Original post, 9/1/09, 3:54pm: The hazy, orange tinted skies over Denver on Monday were an unusual sight and a result of smoke traveling hundreds of miles from wildfires across the western United States. Satellite imagery released by NASA and the National Oceanic and Atmospheric Administration (NOAA) showed plumes of smoke moving northwest toward Colorado from as far away as Los Angeles.

The National Interagency Fire Center (NIFC) reported 17 fires burning in states from Colorado west. Seven fires in California, three in Utah and two in Colorado are the primary ones causing smoke over the Mile High City.

The largest of the blazes, the Station Fire in the foothills near Los Angeles, exploded to more than 120,000 acres in recent days. In Utah, the Mill Flats Fire burning in the Dixie National Forest grew to more than 10,000 acres.

Colorado reports two wildfires, the largest of which has been dubbed the Tabaguache Creek Fire in the Uncompahgre and Gunnison National Forests. That blaze is six miles north of Nucla and has scorched 1,260 acres.

Altogether, the fires that are actively burning have burned more than 150,000 acres of land. For the entire fire season which runs during the calendar year, 65,140 wildfires have been reported and an estimated 5,303,691 acres – more than 8,000 square miles – have been burned.

Tuesday the smoke has eased some over the Front Range and it should dissipate this evening.

There's more to this story on the Denver Weather Examiner's site!We offer in depth coverage of the wildfires and other climate and weather topics on our Denver Weather Examiner pages.  Check it out!

From the Colorado Department of Public Health and Environment:

COLORADO SMOKE ADVISORY & OUTLOOK:

Significant smoke from fires in Canada, Utah, Colorado, California and other western states will cause widespread haze in Colorado on Tuesday and from time-to-time this week. Fine Particulate levels are in the Unhealthy-for-Sensitive-Groups category in Garfield County and are probably in the Unhealthy-for-Sensitive-Groups range in other areas across Northwest and North-central Colorado due to the smoke from the forest fires. The highest concentrations are expected to occur in Northwest and North-central Colorado, generally north of I-70, possibly as far east as the Front Range. Much of the rest of Colorado will see concentrations in the Moderate range. IF VISIBILITY IS LESS THAN 5 MILES IN SMOKE IN YOUR NEIGHBORHOOD, SMOKE HAS REACHED LEVELS THAT ARE UNHEALTHY. If smoke is thick or becomes thick in your neighborhood you may want to remain indoors. This is especially true for those with heart disease, respiratory illnesses, the very young, and the elderly. Consider limiting outdoor activity when moderate to heavy smoke is present. Consider relocating temporarily if smoke is present indoors and is making you ill. Smoke should gradually diminish later this evening in most areas.

For satellite analysis of smoke over the U.S., visit: http://www.firedetect.noaa.gov/viewer.htm

Moderate to heavy smoke is also possible in the vicinity of a fire 6 miles north of Nucla, especially in areas down-valley of the fire during the nighttime and morning hours.

FRONT RANGE AIR QUALITY FORECAST:

Ozone is expected to be in the Moderate to Unhealthy-for-Sensitive-Groups range Tuesday afternoon and evening (with the highest readings in the Denver metro area) and in the Moderate category on Wednesday. Active children, active adults, and people with respiratory illnesses should limit prolonged outdoor exertion from 2 PM until midnight tonight.

Visibility is expected to remain in the Poor Category on Tuesday and Wednesday.

Carbon monoxide levels are expected to remain in the Good category along the Front Range on Tuesday.

Fine particulate matter levels are expected to be in the Moderate category along the Front Range on Tuesday and Wednesday

Colorado Weather

3.9 magnitude earthquake rocks southeastern Colorado

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In a bit of a rarity for the Centennial State, Colorado experienced a 3.9 magnitude earthquake Sunday evening. According to the U.S. Geological Survey, the quake was centered nine miles east of Eads or 26 miles north of Lamar in the southeastern part of the state.

No damage was reported but the temblor was felt into western Kansas. Mary Breslin of Eads told the Denver Post she felt the shaking. “I really thought it was an explosion,” Breslin said. “It did not occur to me in the beginning that it was an earthquake.”

Originating at a depth of 6.2 miles, the quake occurred at 6:22pm along what state geologist Vince Matthews told the Associated Press might be part of a previously unmapped extension of the Cheraw Fault. See below for complete technical details on the quake.

There's more to this story on the Denver Weather Examiner's site!For more details on this temblor including maps and a look at Colorado’s earthquake history, view the complete story on Examiner.com.

Colorado Weather, Thornton Weather

A new record low maximum temperature set & snow comes to the mountains

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Denver has record setting cool temperatures and snow arrives in the Rocky Mountains. Image courtesy Victor Lewis.
Denver has record setting cool temperatures and snow arrives in the Rocky Mountains. Image courtesy Victor Lewis.

While some parts of the nation experience record setting heat, on Thursday Denver had the opposite problem. The high temperature as measured at Denver International Airport reached a mere 64 degrees. This was two degrees below the previous record low maximum temperature of 66 degrees for this date set in 1925 and previous years. That is also an amazing 24 degrees below the normal temperature for this time of year!

Here in Thornton, we were even cooler than the official temperature on Thursday as the mercury climbed to a mere 61.3 degrees! 

The unseasonably cold weather has also brought an unusual sight to the Colorado mountains in July – snow! Some northern parts of the Rocky Mountains in the state above 12,000 feet received a couple inches of snow.

Colorado Weather, Severe Weather

Denver storm costs $350 million – Second most in state history

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A man surveys damage to a vehicle struck by a fallen tree after last week's storms. The June 20th hail and wind storm has racked up costs of $350 million in insurance claims. Image courtesy Becki Mullen.
A man surveys damage to a vehicle struck by a fallen tree after last week's storms. The June 20th hail and wind storm has racked up costs of $350 million in insurance claims. Image courtesy Becki Mullen.

Last week’s hail and wind storm that brought destruction to the west Denver suburbs of Wheat Ridge and Arvada caused $350 million in insured damage according to the Rocky Mountain Insurance Information Association (RMIIA).  The end result is a storm that now ranks as the second costliest in state history and adds to an already expensive summer storm season.

The July 20th storm has thus far resulted in 52,400 claims, 19,500 of which were for automobile damage and 32,900 were homeowner claims.  RMIIA says that damage would have been much higher had the storm struck during daylight hours when more people and vehicles were on the road instead of in their homes and garages. 

Massive trees were uprooted, power poles snapped, windows shattered, and automobiles dented beyond repair when the storm brought winds in excess of 60 mph and golf ball sized hail to the area.  Two tornadoes also briefly touched down near Castle Rock and Englewood although they were not responsible for significant damage.  90,000 people lost power during the storm and Xcel Energy deployed more than 200 people into the field to restore electricity. 

There's more to this story on the Denver Weather Examiner's site!For all the details, including amazing images and video of the damage, view the complete story on Examiner.com.

Climatology, Colorado Weather, Thornton Weather

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

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July 12 to July 18 - This week in Denver weather history
July 12 to July 18 - This week in Denver weather history

A busy week in Denver weather history for sure.  Most notable are the occurences of flooding that seem to happen with regularity as well as the costliest hail storm in American history.

11-12

In 1872…heavy rain from 4:00 pm until 2:00 am caused much damage.  Rainfall totaled 1.76 inches.

12   

In 1881…during the early evening…a brisk rain fell for 30 minutes from a nearly clear sky containing not one tenth of clouds with the sun shining brightly.  Rainfall was 0.16 inch.
 
In 1885…thunderstorms produced widespread lightning across the city during the evening.  Several people were injured when their homes were struck by lightning.
 
In 1954…the high temperature reached 101 degrees at Stapleton Airport.
 
In 1962…lightning struck and killed a Denver man…while he was assisting a co-worker with his car.
 
In 1971…the temperature climbed to a high of 101 degrees at Stapleton International Airport.
 
In 1974…hail to 3/4 inch in diameter fell in Castle Rock.
 
In 1991…hail to 2 inches in diameter fell in Thornton with golf ball size hail in Brighton.  Dime size hail was recorded in the city of Denver.  Very heavy rain caused flooding across metro Denver.  Water was up to 2 feet deep in parts of Golden where one foot of water was reported in the lot of a mobile home park.  Flood water washed away part of a parking lot at the Colorado school of mines in Golden. Heavy rain caused a rock slide and flooding along I-70 in the foothills just west of Denver.  Flood waters were a foot deep at the intersection of I-70 and I-25 just north of downtown Denver.  A funnel cloud was sighted just east of the rocky mountain arsenal.
 
In 1996…very heavy rainfall from a fast moving thunderstorm dumped 2 to 3 inches of rain within an hour over southern Jefferson County.  Two people were killed near the town of buffalo creek when a 20-foot wall of water flooded the area.  Utility poles and trees were uprooted; cars… Propane tanks…and bridges were destroyed in the flood’s path.  Entire buildings were moved from their foundations and heavily damaged by the floodwaters.  The first fatality occurred along State Highway 126 when the driver of a pick-up truck was washed off the road by the deadly wall of water.  The second death occurred farther upstream when a man in a 5th-wheel trailer was washed away.  This was the second disaster to strike the area in the last couple of months.  The community was already recovering from a wildfire which burned about 12 thousand acres of forest land in late May.  With the forest burned by fire…very little vegetation was available to slow the storm’s runoff…which resulted in the flash flood.  Power…water…and sewer service were heavily damaged in the flood and…in some cases…beyond repair.  The cost of repairing the roads and water system in the area was estimated at around a half million dollars.  Elsewhere across metro Denver…severe thunderstorms produced hail…damaging winds…and small tornadoes.  Weak tornadoes (f0) were reported in Broomfield… 3 miles east of Englewood…and in Dacono.  No damage was reported…except a trampoline was blown into a window and several trees were downed in Broomfield.  Thunderstorm wind gusts estimated as high as 60 mph blew a fence down in Louisville where winds also toppled a tree near a house. The house received only minor damage.  Large hail…strong winds and heavy rain caused substantial property damage in portions of southeastern Boulder and northern Jefferson counties.  Damage estimates in the Broomfield area alone were about 1 million dollars.  Winds gusted to 81 mph in Broomfield.  Large hail…3/4 to 1 1/2 inches in diameter fell in Evergreen…Lakewood…Englewood…Broomfield…near Morrison…northeast of Boulder…and just east of Denver International Airport.
 
In 2000…heavy rain fell across a portion of the hi meadow fire burn area near buffalo creek…causing localized flooding.  About 3/4 inch of rain fell in 30 minutes over miller gulch.  Some culverts become plugged by debris from the fire.  As a result…small sections of a u.s. forest service road along miller creek were washed out.  Lightning struck a home in Castle Rock…causing extensive damage to the roof…attic…and second floor.

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

Climatology, Colorado Weather, Thornton Weather

July 5 to July 11 – This week in Denver weather history

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July 5 - July 11 - This week in Denver weather history.
July 5 - July 11 - This week in Denver weather history.

Our look back at this week in Denver weather history reminds us that severe weather can continue to strike, even during what is normally a relatively calm month.  Lightning, hail and flooding are three continuous threats as we see during our look back at history this week.

From the National Weather Service:

29-15

In 2000…the 29th marked the beginning of a near record hot streak for metro Denver.  The high temperatures…as recorded at Denver International Airport…exceeded the 90 degree mark for 17 consecutive days from June 29th through July 15th. This was one day short of equaling the all time record.  The record of 18 consecutive 90 degree or above days was first set from July 1st through July 18th…1874.  The record was equaled from July 6th through July 23rd…1901.

4-5  

In 1875…nearly every railroad running into the city was damaged by heavy thunderstorm rains.  The heavy rains washed out wooden bridges over normally dry creeks. Some trains were entirely suspended.  In the city…heavy thunderstorm rain totaled 1.05 inches on the 4th…but only 0.28 inch on the 5th.

4-8  

In 1989…one of the most intense heat waves on record roasted metro Denver.  The temperature reached 100 degrees or more on 5 consecutive days.  The city had previously never recorded more than 2 straight 100-degree days since records began in 1872.  Water and electricity usage reached all time highs.  The heat wave created extremely dry weather conditions…which contributed to a major forest fire in Boulder canyon on July 9th.  The temperature reached 103 degrees on the 8th…and the mercury climbed to 101 degrees on both the 4th and 5th…and to 102 degrees on both the 6th and 7th.  The low temperature of 68 degrees on the 8th equaled the record high minimum for the date.

5    

In 1908…a late evening thunderstorm produced sustained north winds to 40 mph…hail…and 0.45 inch of precipitation.
 
In 1949…a dust devil…possibly a small tornado…was observed 3 miles to the northwest of Stapleton Airport.
 
In 1973…the temperature reached 100 degrees at Stapleton International Airport.
 
In 1974…strong thunderstorm winds damaged a mobile home…a barn…two houses…and several sheds near Watkins.
 
In 1975…a thunderstorm wind gust to 53 mph was recorded at Stapleton International Airport.  Hail up to 3/4 inch in diameter fell over the northwest suburbs and in northwest Denver.
 
In 1977 three houses in Denver were struck by lightning. Some heavy damage and fire occurred.
 
In 1990…lightning caused minor damage to houses in Castle Rock…Louviers…and Littleton.
 
In 1996…lightning caused only minor damage when it struck a home in Evergreen.  Lightning from a fast moving thunderstorm blasted a large hole in the side of a house in Lakewood.  Lightning triggered a minor power outage in the Boulder area.  About 200 homes were affected.
 
In 2001…severe thunderstorm winds gusted to 60 mph at Denver International Airport and to 70 mph…7 miles southwest of the airport.
 
In 2008…microburst winds downed a large tree and some power lines near a Denver apartment complex.  Several of the tenants’ vehicles were damaged.

Continue reading July 5 to July 11 – This week in Denver weather history →