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.
As summer vacations wind down and families prepare to send their kids back to school in August, Colorado weather also starts to settle down. The chances for severe weather decrease markedly during August and by the end of the month daytime temperatures are dropping quite a bit as well.
At the start of the month Denver usually averages around 88 degrees for a high temperature. By the end of August that drops to 82 degrees. Similarly, nighttime lows drop from 60 to 53 from the start to the end of the month. Generally clear skies can be expected between midnight and noon but the afternoon often brings showers and thunderstorms. These storms typically develop over the foothills then bring precipitation to the Denver metro area.
Despite that moisture, the chance for severe weather decreases considerably compared to the first two months of summer. Cooler air near the surface helps to create a stable atmosphere thus keeping thunderstorms from usually becoming too intense. After the middle of August, tornadoes and damaging hail are pretty rare. The slow movement of storms this time of year are more likely to produce potentially heavy rain.
A new study says he El Niño-Southern Oscillation (ENSO) accounts for the vast majority of temperature variability.
A new peer-reviewed study calls into question the so-called ‘consensus’ on the causes of global warming by saying that “Nature, not man, responsible for recent global warming.” The new study authored by three Australian scientists and published in the Journal of Geophysical Research says that the El Niño-Southern Oscillation (ENSO) accounts for the vast majority of temperature variability.
Authored by Chris de Freitas (University of Auckland in New Zealand), John McLean (Melbourne) and Bob Carter (James Cook University), the new study is sure to cause waves among those debating the causes of global warming. Completely contrary to the mainstream media’s portrayal of climate change, the study says, “little or none of the late 20th century global warming and cooling can be attributed to human activity.”
Lead author de Freitas said in a press release, “The surge in global temperatures since 1977 can be attributed to a 1976 climate shift in the Pacific Ocean that made warming El Niño conditions more likely than they were over the previous 30 years and cooling La Niña conditions less likely.”
July 26 to August 1 - This week in Denver weather history
Weather can be deadly – we are all well (hopefully) aware of that. Looking at this week in Denver weather history we are reminded of that and the tragedy that weather can bring to our state. We see numerous cases of lightning causing death and injury but no one incident highlights the dangers of weather more than what occurred on July 31, 1976. The Big Thompson Flood was Colorado’s worth weather-related disaster and claimed 144 lives. More details on all these events are below.
13-5
In 2008…a streak of 26 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874. Ironically…no new single day record high temperatures were set in the month of July. In August however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on August 2nd.
26
In 1891…a thunderstorm produced sustained northeast winds to 44 mph with gusts to 60 mph and 0.16 inch of rain.
In 1894…a thunderstorm produced sustained southwest winds to 36 mph with gusts to 58 mph…but only 0.04 inch of rain.
In 1910…the high temperature reached 100 degrees in downtown Denver.
In 1959…a Denver man was stunned while standing by a car that was struck by lightning. He was treated for burns and shock at a local hospital. Thunderstorm winds gusted to 55 mph at Stapleton Airport.
In 1983…two heavy thunderstorms hit the northern and western suburbs. The first drenched Northglenn with an inch of rain in 30 minutes. The second storm dumped an inch or more of rain in Idaho Springs and Evergreen. The heaviest rainfall… 2.90 inches in an hour…caused minor street flooding in Golden.
In 1984…heavy early morning thunderstorms drenched the foothills southwest of Denver. Rainfall to 1 1/2 inches in just 30 minutes occurred between Evergreen and Conifer. In nearby turkey creek canyon…1.80 inches of rain was recorded in 35 minutes.
In 1985…a long rope-like white tornado touched down 5 miles east of Erie and stayed on the ground…mainly over an open field…for 18 minutes. However…the twister damaged a few cars on I-25 and injured 3 people from broken glass. The storm flipped over a van…blew out car windows…and ripped a highway sign. It also blew an outbuilding off its foundation. A tornado also touched down briefly 8 miles north of Bennett. No damage was reported from this storm.
In 1988…a 9-year-old girl was slightly injured by lightning in Parker.
In 2003…a severe thunderstorm in and south of Franktown produced hail as large as 1.75 inches in diameter.
July 19 to July 25 - This week in Denver weather history
This week in weather history we really begin to see the arrival of monsoon season and the heavy rains and flooding it can bring to the Thornton and Denver area. Be sure to check out the events on the 23rd and what the heavy rain brought to the Thornton area in 2004.
13-5
In 2008…a streak of 26 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874. Ironically…no new single day record high temperatures were set in the month of July. In august however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on august 2nd.
18-19
In 2003…heavy rain producing thunderstorms caused flash flooding across southern metro Denver. Automated rain gages measured 2 to 3 inches of rain in less than an hour. The heavy rainfall caused many intersections and underpasses to flood…stranding motorists. Sections of I-25 and I-225 were closed due to the high water.
19
In 1875…recent heavy rains produced high waters on many creeks and rivers in the area…which threatened the destruction of property at some locations. Cherry Creek in the city was running the highest in 10 years. Heavy rain in the mining regions over the last 2 days resulted in water running “everywhere” and the suspension of some work.
In 1881…a thunderstorm passing across the city produced lightning with no rain. A woman was seriously injured when struck by lightning several blocks from the weather office in downtown Denver.
In 1934…the temperature reached a high of 100 degrees in downtown Denver.
In 1965…hail…rain…and lightning hit west metro Denver. Hail stones as large as 1 1/2 inches in diameter accumulated to a depth of 2 inches in Evergreen where 2.95 inches of rain in 2 hours caused some flooding in the business section of the town. Lightning caused some power outages.
In 1973…two funnel clouds were observed 5 miles southeast of Littleton. The same funnel clouds were observed for 20 minutes…5 miles west and 5 miles west-southwest of Arapahoe County airport…now Centennial Airport.
In 1975…lightning injured a man in Denver and caused power outages in Aurora…Lakewood…Westminster…and west Denver.
In 1984…strong thunderstorm winds gusting to 45 mph shattered 7 large plate glass windows at Stapleton International Airport.
In 1985…a tornado touched down in the surrey ridge area of northern Douglas County…just west of I-25. Ten homes were damaged; one under construction was nearly destroyed. Two vehicles were thrown off I-25 injuring three people. A pick-up truck was thrown 50 feet by the twister. In addition…a cluster of severe thunderstorms pounded all of metro Denver with torrential rain…hail…and wind. The heaviest rain fell in Aurora where one location reported 2.37 inches in just 40 minutes. One location in northeast Aurora received a total of 4.30 inches from the storm. There was extensive street and basement flooding…and a number of roads were damaged or washed out. An Aurora boy suffered minor injuries when he was washed into a drainage ditch. Golf ball size hail in Aurora piled up to 5 inches deep. An inch of rain fell in 20 minutes at Stapleton International Airport…closing it to air traffic for an hour. Up to 1 1/2 inches of rain fell in just 15 minutes over central Denver with the high water closing I-25. The water was so deep on the freeway…that one vehicle was completely submerged and people were diving into the water from the freeway overpass. Three homes in Littleton were damaged by lightning. Wind blew out several windows from a high rise apartment building in southeast Denver. Rainfall totaled 1.51 inches at Stapleton International Airport.
In 1997…torrential rain and damaging hail pummeled eastern sections of metro Denver. Hail up to 1.25 inches in diameter fell at the national weather service office on the site of the former Stapleton International Airport. The hail continued for about 15 minutes and accumulated to a depth of 2 to 3 inches…causing extensive damage to cars in the area. Heavy rainfall totaled 3.83 inches in about an hour from the nearly stationary thunderstorm. Numerous cars stalled along I-70…and several homes were flooded in east Denver. The roof of a building collapsed under the weight of the water. The next day several “fatalities” were discovered near the national weather service office; two prairie dogs were found dead along with three rabbits that either drowned or were killed by the large hail.
In 1999…lightning struck two residences in Littleton…but caused only minor damage. Lightning triggered a fire at a residence in cherry hills village. A small portion of the roof and ceiling were damaged before the fire could be extinguished.
In 2000…hail as large as 1.25 inches in diameter fell near Roggen northeast of Denver.
In 2004…heavy rainfall caused flooding on the Virginia Canyon Road near Idaho Springs…which had to be closed for repairs.
In 2006…the temperature climbed to a high of 100 degrees. The high temperature was not a record maximum for the date.
In 2007…a severe thunderstorm produced large hail…up to 1 inch in diameter…about 6 miles north of Northglenn.
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.
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.
Do these clouds have the potential to bring a tornado? Learn more at National Weather Service storm spotter training.
We have written before about the great opportunity the National Weather Service provides by giving storm spotter training during the start of the severe weather season. Normally these sessions are held in the spring but in response to the very active severe weather of early June, and the increased interest in severe thunderstorms, the National Weather Service in Boulder has added to additional spotter training session next week.
When: Saturday, July 11
Time: 10:00am
Where: Broomfield, CO.
Exact location: Rocky Mountain Metropolitan Airport, Terminal Building, 11755 Airport Way (formerly Jefferson County Airport)
The storm spotter program is a nationwide program with more than 280,000 trained spotters. These volunteers report weather hazards to their local National Weather Service office providing vital information when severe strikes. Data from spotters include severe wind, rain, snow measurements, thunderstorms and hail and of course tornadoes.
Storm spotters are part of the ranks of citizens who form the Nation’s first line of defense against severe weather. There can be no finer reward than to know that their efforts have given communities the precious gift of time–seconds and minutes that can help save lives.
By completing one of these training classes you can become an official storm spotter. When severe weather strikes, you can report it by calling a special toll free number or submit your report via the National Weather Service’s website.
Taking the training though doesn’t obligate you to being a storm spotter. These are great sessions for anyone wanting to learn more about the severe weather we experience in Colorado, whether you want to be an official spotter or not. All training is free. Topics include:
This funnel cloud was seen on Tuesday from the Thornton Civic Center (looking north) on June 10th. Image courtesy Lisa Wilson, the City of Thornton.
June 2009 went down in the history books as one of the more unusual June’s on record. Residents are all of course well aware of the string of severe storms but the Mile High City also were unusually cool and certainly very wet.
In terms of precipitation, a whopping 4.86 inches of rain fell at the official measuring site at Denver International Airport during the month – the second wettest June since recordkeeping began here in 1872. We missed out on breaking the record by only a tenth of an inch as the all-time wettest was back in 1882 when 4.96 inches fell in the rain bucket. Nevertheless, we easily exceed the normal rainfall total for the month which is 1.56 inches. In fact, we beat that in one day on June 23rd when 1.64 inches fell at DIA. Here in Thornton we didn’t measure near as much precipitation having recording 3.44 inches for the month. This is more in line with what areas closer to the actual metro area recorded than what was recorded at DIA. See below for details on the controversy about Denver’s climate records.
Temperature wise, we were very cool as well, never breaking the 90 degree mark during the month. Two days, the 29th and 30th, came close with 89 degrees being recorded as the high temperatures on those days. This was the first time since 2003 no 90 degree days were recorded in June. Before that, you would have to go way back to 1972 to find another June when that happened. The average temperature for June 2009 was 64.4 degrees, 3.2 degrees below the normal of 67.6. That may be cool but it was nowhere near the record low average for June which is 60.6 set in 1967. Thornton was just a touch warmer than the official stats from DIA as we recorded 90.0 degrees on the 29th. Similarly, Thornton’s average temperature was just a bit cooler at 63.2 degrees.
Then of course there were the storms. Tornadoes, funnel clouds and hail will probably be the most memorable events of the month, especially the twister that struck the Southlands Shopping Center in Aurora. In all, DIA recorded 18 days with thunderstorms – eight more than normal. 15 days had precipitation versus the normal of nine. All those storms also took a toll on what is normally a sunny month. On average Denver has 70 percent of possible sunshine during the month. This year we only recorded sunshine 51 percent of the time.
All that rain we have received in the last two months, especially in June, helps to make one other statistic a bit more tolerable. Colorado’s snow season runs from July 1 to June 30 each year and for the 2008 – 2009 snow season, we recorded a meager 38.1 inches of the white stuff. That is a whopping 29 inches below the normal of 67.1 inches. Thornton fared a bit better on the snowfall front but not by a lot having recorded 48.5 inches for the season.
There is always a ‘but’…
As always, we would like to remind everyone that all official Denver weather statistics are now taken out at Denver International Airport. As we outlined a few months ago, moving the official monitoring station 13 miles away has made quite a difference in Denver’s climate records. Evidence suggests that temperatures and precipitation as measured at DIA differ greatly from what would have been recorded at the old site at Stapleton or near downtown Denver.
The National Weather Service has finally acknowledged this and has setup a measuring station at the Denver Museum of Nature and Science (click here to view current conditions from it on the Weather Underground). However, they maintain that Denver’s official statistics will continue to be recorded at DIA and as a result, Denver’s climate records will forever have an asterisk next to them. If you compare June’s statistics from this new station to the ‘official’ ones at DIA, you will notice that much of what we discuss above, including the temperature and precipitation, would be much different were the statistics being kept by the new station closer to where people actually live.
Denver climate summary for the month of June 2009 – From the National Weather Service
CLIMATE NORMAL PERIOD 1971 TO 2000
CLIMATE RECORD PERIOD 1872 TO 2009
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S
VALUE DATE(S) VALUE FROM VALUE DATE(S)
NORMAL
................................................................
TEMPERATURE (F)
RECORD
HIGH 104 06/26/1994
LOW 30 06/02/1951
HIGHEST 89 06/30 104 -15 95 06/26
06/29
LOWEST 41 06/08 30 11 37 06/12
AVG. MAXIMUM 77.7 82.1 -4.4 83.9
AVG. MINIMUM 51.1 53.0 -1.9 50.9
MEAN 64.4 67.6 -3.2 67.4
DAYS MAX >= 90 0 6.3 -6.3 10
DAYS MAX <= 32 0 0.0 0.0 0
DAYS MIN <= 32 0 0.0 0.0 0
DAYS MIN <= 0 0 0.0 0.0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 4.96 1882
MINIMUM T 1890
TOTALS 4.86 1.56 3.30 0.73
DAILY AVG. 0.16 0.05 0.11 0.02
DAYS >= .01 15 8.7 6.3 4
DAYS >= .10 9 MM MM 2
DAYS >= .50 4 MM MM 1
DAYS >= 1.00 1 MM MM 0
GREATEST
24 HR. TOTAL 1.64R 06/23 TO 06/23 0.70 06/04 TO 06/05
SNOWFALL (INCHES)
RECORDS
TOTAL 0.4 1919
TOTALS 0.0 T
DEGREE_DAYS
HEATING TOTAL 78 60 18 64
SINCE 7/1 5616 6128 -512 6056
COOLING TOTAL 68 136 -68 144
SINCE 1/1 94 161 -67 172
FREEZE DATES
RECORD
EARLIEST 09/08/1962
LATEST 06/02/1951
EARLIEST 10/07
LATEST 05/05
.................................................................
WIND (MPH)
AVERAGE WIND SPEED 8.4
RESULTANT WIND SPEED/DIRECTION 2/147
HIGHEST WIND SPEED/DIRECTION 53/260 DATE 06/26
HIGHEST GUST SPEED/DIRECTION 68/270 DATE 06/26
SKY COVER
POSSIBLE SUNSHINE (PERCENT) 51
NUMBER OF DAYS FAIR 3
NUMBER OF DAYS PC 22
NUMBER OF DAYS CLOUDY 5
AVERAGE RH (PERCENT) 65
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 18 MIXED PRECIP 1
HEAVY RAIN 7 RAIN 10
LIGHT RAIN 17 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 3
HEAVY SNOW 0 SNOW 0
LIGHT SNOW 0 SLEET 0
FOG 14 FOG W/VIS <= 1/4 MILE 6
HAZE 10
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
Dissenters within the EPA have called into question the global warming theory.
The Environmental Protection Agency, keen to advance President Barack Obama’s climate change initiatives, apparently suppressed a report from leading experts calling into question the science behind the theory of manmade climate change. The 98-page report, submitted to agency leaders just prior to it recommending regulation of carbon dioxide emissions, continues to call into question the ‘consensus’ many have said the scientific community has about the theory.
Alan Carlin, the report’s primary author, was told via email from superiors in the agency to not “have any direct communication” with anyone outside his group at the EPA. The well-published PhD has experience in environment and public policy dating back to 1964 but after submitting the report was told to discontinue working on climate change entirely.
In reviewing the report, it is obvious why the administration would find the report very untimely leading up to its decision on CO2 and its push for climate change legislation. The report authors saw the rush to judgment and urged caution saying their “concerns and reservations are sufficiently important to warrant a serious review of the science by EPA before any attempt to reach conclusions on the subject.”
