Fall officially begins tomorrow at 7:54pm and we have some darn nice weather to welcome the change of seasons. Friday will be cooler than we have seen of late, but near normal, then the weekend rebounds with above normal temps.

Sunny skies with only a few clouds here and there will be above Friday. Conditions will be calm other than some breezy winds in the late afternoon and evening. Highs today will top out in the mid to upper 70s, right near the average high of 76 for the date. Tonight, skies will be clear and temperatures on the cool-side with lows in the upper 40s.

Saturday sees the mercury rebound with highs in the mid-80s. Clear skies will be above and conditions calm and dry. Saturday night into Sunday morning, skies will be mostly clear with lows dipping to the lower 50s.

Sunday will be the warmest day of the three day period with highs in the mid to upper 80s. Lots of sun will be above and again conditions will be dry.

Have a fantastic weekend!

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.

• Images from recent years’ seasons:
  • September 2015 photo slideshow
  • October 2015 photo slideshow
  • October 2016 photo slideshow
  • October 2017 photo slideshow

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)

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. Be forewarned though that the western half of the pass is unpaved and twisty.  Editor’s note: The west side of Cottonwood Pass is closed until sometime this fall so that it can be paved.

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!

• Email: info@ThorntonWeather.com
• Facebook: https://www.facebook.com/ThorntonWeather
• Google+: https://plus.google.com/+Thorntonweather
• Twitter: @ThorntonWeather (https://twitter.com/thorntonweather)

For more information:

• Colorado.com: Colorado Fall Foliage Drives
• Colorado State Parks: 7 Ways to Enjoy Fall Colors
• Colorado State Forest Service Aspen Fall Colors

The heat finally breaks as Thornton cools down quite a bit Thursday. Yesterday we never did get quite as hot as expected and put an end to that ridiculous 90+ degree streak with some nice rain. Today, we dry out and remain cooler (but still warmer than normal).

The day will start out with a good bit of cloud cover but we will see clearing throughout the day leading to mostly sunny skies for the afternoon.

Temperatures today will top out in the low 80s. Average for the date is 77 degrees so we will still be warmer than normal but that is far better than the recent heat.

Tonight, skies will be mostly clear and lows could dip to the upper 40s.

Finally a break! Today will still be quite warm but an approaching cold front that arrives later will offer cooler weather and a chance for showers.

The day starts out with mostly sunny skies but by mid-morning we will see a gradual increase in mid and upper level clouds.

Highs today will top out near the 90 degree mark in the early to mid-afternoon but, a cold front will then arrive and cool things down somewhat quickly through the evening.

Some scattered showers / thunderstorms will be possible from mid-afternoon into tonight with the best chances coming from about 6:00pm to 10:00pm. We don’t expect a lot of precipitation but we could finally see something that counts in the rain bucket.

Tonight, a few showers may linger overnight into the pre-dawn hours tomorrow. Overnight lows will be in the mid to upper 50s.

Looking ahead, cooler weather is expected through the weekend. See the extended forecast here.

Yup, yet another forecast where we could pretty much cut and paste the previous day’s forecast. Lots of sun will be above today (again) and temperatures will climb toward record highs (again).

We start out under sunny skies and then, much like yesterday, the afternoon will offer up a few clouds but nothing that will lead to precipitation.

The record high temperature in Denver for today’s date is 93 degrees and we are going to be pushing close to that mark. Tonight, skies will be partly cloudy with lows in the mid to upper 50s.

On the plus side, tomorrow we do expect to start to see things change. While Wednesday will also be unseasonably warm, it will be cooler than today and thanks to increased moisture and a cold front, we may see some precipitation.

No rest for the weary, at least not for the first half of this week. We will continue to see temperatures well above normal today and for the next few but relief does appear on the way later this week.

For today, sunny skies start things out then we should have a few clouds for much of the day although nothing that will do much to inhibit temperatures.

Highs today will once again climb into the 90s, far above the average high for today’s date of 78 degrees.

Tonight, partly cloudy skies will be above with a low around 60 degrees.

Looking ahead, tomorrow promises more of the same heat. A cold front is expected to arrive Wednesday and that will start us on a bit of a downward trend that should bring temps close to normal Thursday through the weekend. More in the extended weather forecast here.

September 16 to September 22: This week in Denver weather history

Given our hot summer some may enjoy a look at what at times has been a cold and snowy week in Denver weather history. Not only one but two major snowstorms have occurred, both very damaging and both brought snowfall amounts we typically see in March, not September.

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.

15-17

In 2000…unusually hot weather for so late in the season occurred when temperatures climbed into the 90’s setting daily record maximum temperatures on each of the 3 days. The high temperature was 92 degrees on the 15th and 95 degrees on both the 16th and 17th.

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

In 1874…a blast of west winds caused minor injuries during working hours in Boulder.

In Denver…the winds veered suddenly from the southwest to the northwest around noon and increased to a maximum sustained speed of 49 mph behind an apparent cold front. The winds remained strong and backed to the west for the remainder of the afternoon.

In 2000…the record high temperature of 95 degrees at Denver International Airport established or equaled 3 different record extremes: the high temperature broke the previous record high for the day of 92 degrees set over a century ago in 1895; it marked the warmest that it has been so late in September; it also marked the 60th day during the warm season that the temperature had reached 90 degrees or more…equaling the record first set on September 29…1994.

In 2006…strong Bora winds behind a pacific cold front raked the eastern slopes of the mountains and metro Denver during the afternoon. Northwest winds were sustained to 40 mph with gusts as high as 54 mph at Denver International Airport.

In 2007…a severe thunderstorm produced a peak wind gust of 67 mph…about one mile east of Bennett. At Denver International Airport…a peak wind gust of 48 mph was observed.

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.

17

In 1873…brisk west to northwest winds at different times during the day…generally in sudden gusts…spread a good deal of dust into the city.

In 1953…strong winds caused thousands of dollars in damage to Boulder. The winds blew for most of the day with great gustiness…and a freak twister was reported during the afternoon. Damage was minor. A thunderstorm wind gust to 40 mph caused some blowing dust at Stapleton Airport.

In 1992…a tornado touched down briefly near Bennett. No damage was reported.

In 1993…severe thunderstorms rumbled across northern portions of metro Denver. Hail as large as 1 3/4 inches in diameter fell in Brighton. Dime size hail damaged several roofs of residences in Lafayette.

In 2000…for the second day in a row…the high temperature of 95 degrees at Denver International Airport broke three record temperature extremes: the high temperature broke the previous record for the day of 94 degrees set in 1895; it marked the warmest it has been for so late in the season; it also marked the 61st day in the year that the temperature had equaled or exceeded 90 degrees…eclipsing the record equaled the previous day and first set on September 29… 1994.

18

In 1901…northeast winds were sustained to 42 mph with gusts to 50 mph behind an apparent cold front.

In 1948…the low temperature cooled to only 69 degrees…the all-time record high minimum for the month.

In 1988…a strong cold front blasted metro Denver with high winds. Gusts reached 82 mph in Longmont and 81 mph at Jefferson County Airport near Broomfield where the winds flipped over and destroyed a small airplane. Wind gusts to 60 mph were recorded in Boulder and wheat ridge. West wind gusts to 54 mph were clocked at Stapleton International Airport. The strong winds downed trees and power lines and damaged homes and cars. A Longmont man was slightly injured…when a tree fell on top of his car.

In 1990…a slow moving thunderstorm over southwest metro Denver spawned an ominous looking funnel cloud near the intersection of Sheridan Blvd. and U.S. Highway 285. The funnel cloud nearly touched down a few times before lifting back into the main cloud. No damage was reported. Pea to marble size hail and 3/4 inch of rain fell over central and northeast Denver. Numerous streets and underpasses became flooded on Denver’s south side when the heavy runoff backed up storm sewers. Thunderstorm rainfall totaled 1.02 inches at Stapleton International Airport.

In 1993…a severe thunderstorm rolled through southeast metro Denver. Dime size hail was reported in many areas. Straight-line winds from the thunderstorm…measured by a weather spotter at 70 mph…tore the roof off 6 apartments of an apartment complex in Aurora. Heavy rain which accompanied the winds caused major damage to the apartments as well as the contents. Many trees…fences… And power poles were knocked down by the strong winds. Heavy rain flooded roadways in Denver and Aurora. Thunderstorm rainfall totaled 1.08 inches and north winds gusted to 44 mph at Stapleton International Airport where the visibility was briefly reduced to as low as 1/4 mile in heavy rain.

In 1996…a late summer snowstorm struck the northern mountains and Front Range eastern foothills. Golden Gate Canyon received 6 inches of new snow with 5 inches reported at both Nederland and Blackhawk. Thunderstorms produced heavy rain across metro Denver…which was mixed with snow by late evening. Rainfall totaled 0.83 inch at the site of the former Stapleton International Airport and 1.22 inches at Denver International Airport where northwest winds gusted to 39 mph.

18-19

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

» Click here to read the rest of September 16 to September 22: This week in Denver weather history

If you were hoping for a break from the late summer heat, don’t bother reading this forecast. A high pressure ridge remains stubbornly in place keeping things hot and moisture away.

For Friday, sunny skies will be the rule with nary a cloud in the sky. Temperatures will be topping out at or just above the 90 degree mark. The record high for today’s date is 92 degrees so we may see our third record high of the week. Tonight, skies will remain clear with lows in the mid-50s.

Saturday is a repeat of today and the previous days. Highs will be in the low 90s with clear skies and dry conditions. The record high for the date is 92 degrees also and again we may see that tied or broken. Saturday night a few clouds may move in and lows will be in the upper 50s.

With a little bit of moisture aloft, we do expect to see a few clouds Sunday but overall, mostly sunny skies should be above. Highs once again will be at or just above the 90 degree mark.

At this time, it looks like it could be the latter half of next week before we see temperatures return to normal levels. In the meantime, keep an eye on the thermometer here.

And down goes another record! We didn’t expect it to get quite as hot as it did but Mother Nature gave the mercury a little extra push into record-setting territory today.

Denver’s official high temperature, as measured at DIA, came in at 96 degrees today.  This tied the record high temperature for September 13 set in 1990 and 1895.

Here in Thornton, we were just a touch cooler as is the norm with a high of 94 degrees.

This is the second high temp record of this week as summer continues to hang on.  Two days ago, Denver broke the record high for September 11.

We wish we could say we were done with the 90+ degree readings for the season but that does not appear to be the case.

Currently it looks like we will be at or a bit above the 90 degree mark through Monday.  It may be the end of next week before we see any appreciable cooling.  Check out the extended forecast here.

This week in Denver weather history: September 9 to September 15

Our look back at this week is shorter than usual owing to the calmer weather we typically see this time of year. That isn’t to say however that there aren’t notable events like a tornado, lightning at the Adams County Fairgrounds that severely injured a man and the Fourmile Canyon wildfire.

From the National Weather Service:

5-9

In 1988…layers of smoke aloft from large forest fires in Yellowstone National Park completely obliterated the sun at times. At Stapleton International Airport…surface visibility was reduced at times to 5 and 6 miles in smoke.

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.

9

In 1933…heavy rain in the foothills over the clear creek and Golden Gate Canyon watersheds caused flooding in Golden and damaged the roadway in Golden Gate Canyon… Which resulted in its closure.

In 1969…a funnel cloud was sighted in southeast Denver. There was also considerable thunderstorm activity and local heavy rain across metro Denver. Rainfall totaled 1.30 inches at Stapleton International Airport where small hail also fell.

In 1973…hail from 3/4 inch to 1 3/4 inches in diameter fell in Westminster and south of Broomfield.

In 2009…a man was critically injured when he was struck by lightning while riding his bicycle. He was nearing a paramedic van when he was hit. His heart stopped but paramedics quickly responded and were able to resuscitate him.

In 2011…a man was struck by lightning at the Adams County fairgrounds. He was leaning against a tree while watching a cross country meet when the tree was hit. The lightning traveled down the tree and up through the ground…using him as a conductor. The victim received second and third degree burns.

9-10

In 1933…heavy rain over the Cherry Creek…plum creek…big dry creek…and little dry creek watersheds caused flooding on the South Platte River in Denver overnight. Nearly an inch of rain…0.98 inch…fell in the city.

In 1944…a trace of rain fell on each day. This together with a trace of rain on the 4th and 30th was the only precipitation for the month. The total of a trace of precipitation for the month equaled the driest September on record first set in 1892.

In 1994…unusually very warm weather resulted in three temperature records being equaled. High temperatures of 94 degrees on the 9th and 93 degrees on the 10th equaled record maximums for the dates. Low temperature of 63 degrees on the 9th equaled the record high minimum for the date.

10

In 1985…golf ball size hail was reported just east of Parker.

In 1989…3/4 inch diameter hail fell in Littleton. Heavy rain produced local flooding in Lakewood. The heavy rain caused the wall of a house to collapse.

In 1993…thunderstorm winds downed power lines…which caused a power outage in Castle Rock.

11

In 1910…west winds were sustained to 42 mph.

In 1951…a vigorous Canadian cold front produced a dust storm across metro Denver. Northeast wind gusts to 43 mph reduced the visibility at Stapleton Airport to as low as 1 1/2 miles for nearly 5 hours. The temperature dropped 47 degrees in 8 hours…from a high of 92 degrees to a low of 45 degrees.

In 1967…a microburst wind gust to 52 mph produced blowing dust and briefly reduced the visibility to 1/2 mile at Stapleton International Airport.

In 1974…a trace of snow…the first of the season…ended the shortest period without snow…94 days from June 9th through September 10th. A trace of snow also fell on June 8th.

In 1995…strong post-frontal winds associated with a fast moving pacific cold front knocked down power poles and trees as it moved through metro Denver. Numerous power outages affected nearly one thousand people in Denver and Jefferson counties. West winds gusted to 34 mph at Denver International Airport.

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.

» Click here to read the rest of September 9 to September 15: This week in Denver weather history