Weather History

April 15 to April 21 – This Week in Denver Weather History

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This Week In Denver Weather History
April 15 to April 21 - This Week in Denver Weather History

Snowstorms, tornadoes and wind, oh my! Our look back at this week in Denver weather history highlights the wide variety of weather we can receive this time of year as we transition from winter to spring.

From the National Weather Service:

12-15

In 1927…snowfall totaled 8.5 inches in downtown Denver. Most of the snow fell on the 14th. Northwest winds were sustained to 27 mph during the storm.

13-15

In 1945…heavy snowfall totaled 9.8 inches in downtown Denver. Most of the snow…4.8 inches…fell on the 14th. Snow fell for a total of 53 consecutive hours. This was the second big snow in less than 2 weeks. The air mass was very cold for April. High temperatures of 21 degrees on the 14th and 32 degrees on the 15th were record low maximums for the those dates.

13-17

In 2001…a huge dust storm over southern and inner Mongolia during April 3rd through the 6th lifted desert dust into the jet stream. This dust cloud moved over metro Denver on the 13th and persisted through the 17th. The cloud created widespread haze…giving the sky a milkish cast due to the scattering of incoming solar radiation.

14-15

In 1873…north winds blew a gale during the afternoon on both days. Winds were brisk throughout each day.

In 1902…snowfall totaled 6.0 inches in downtown Denver. Most of the snow melted as it fell. Northeast winds were sustained to 20 mph.

In 1910…strong winds occurred on both days. Northeast winds were sustained to 52 mph on the 14th. North winds were sustained to 44 mph on the 15th.

In 1921…heavy snowfall and strong winds produced near- blizzard conditions in the city. Snowfall totaled 10.0 inches. Strong north winds sustained to 48 mph with gusts to 54 mph on the 15th produced drifts to several feet in depth. The heavy wet snow caused extensive damage to trees…utility poles…and buildings. Precipitation from the storm was 1.73 inches. Very heavy snow also fell in the foothills. At Silver Lake…in the mountains west of Boulder…95 inches of snow fell in 32.5 hours on the 14th and 15th.

In 1935…dense dust…apparently behind a dry cold front… Enveloped the city at 1:00 pm on the 14th and persisted through the night. The dust blew into the city on northeast winds sustained to 30 mph with gusts to 32 mph. By mid-morning on the 15th…the dust had become light and continued as such into the evening. North winds were sustained to only 13 mph on the 15th.

In 1999…a spring storm dumped heavy snow over portions of metro Denver. Nearly 2 feet of snow fell in the foothills with half a foot to a foot over western and southern suburbs. The heavy snow alleviated drought conditions and associated high fire danger that prevailed during much of the winter season. Snowfall totals included: 22 inches in Coal Creek Canyon…20 inches at Wondervu…19 inches at Genesee…17 inches near Evergreen and Nederland and at Idaho Springs and Tiny Town…14 inches at Georgetown…13 inches at Morrison…10 inches near Sedalia…9 inches in south Boulder… 8 inches at Highlands Ranch and Wheat Ridge…and 7 inches at Littleton and Parker. Only 3.4 inches of snow fell at the site of the former Stapleton International Airport. North- northwest winds gusted to 41 mph on the 15th at Denver International Airport.

15

In 1874…light snow developed around daybreak and became moderate to heavy by mid-morning and continued into the early evening. While most of the snow melted as it fell… Total precipitation from the melted snow was 0.95 inch. This would make the estimated snowfall nearly 10 inches.

In 1963…high winds were widespread across metro Denver. West winds gusted to 63 mph in Denver at Stapleton Airport with sustained winds of 35 mph and gusts to 70 mph in downtown Boulder. The winds caused extensive damage to buildings and other property. Visibility was briefly reduced to 1/2 mile in blowing dust at Stapleton Airport.

In 1998…another spring storm brought heavy snow to the foothills. Thirty to 40 vehicles were involved in accidents along I-70 near Georgetown. The combination of poor visibilities…slick roads…and careless drivers led to the multi-car pileups. Only minor injuries were reported. The accidents forced the closure of all of I-70’s eastbound lanes. Snowfall totals included 12 inches at Genesee and 10 inches at Aspen Springs…Chief Hosa…Georgetown…near Morrison…and on North Turkey Creek. Only 0.1 inch of snow fell at the site of the former Stapleton International Airport. East winds gusted to 30 mph at Denver International Airport.

In 2002…unseasonable warm weather resulted in two records being broken. The high temperature of 84 degrees was a record maximum for the date. The low temperature of 57 degrees was a record high minimum for the date.

Continue reading April 15 to April 21 – This Week in Denver Weather History →

Weather History

April 8 to April 14 – This Week in Denver Weather History

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This Week In Denver Weather History
April 8 to April 14 - This Week in Denver Weather History

April in Denver can bring a wide array of weather conditions, many of which appear in their most extreme form. Our look back at this week in Denver weather history demonstrates this with everything from major snowstorms to damaging windstorms to even a tornado.

From the National Weather Service:

6-8

In 1973…a major spring snow storm dumped 11.6 inches of snowfall over metro Denver. North wind gusts of 30 to 35 mph produced some blowing snow. Most of the heavy wet snow… 10.1 inches…fell on the 7th when temperatures remained in the 20’s. Snow accumulated on the ground to a maximum depth of 9 inches. Low temperature of 5 degrees on the 8th was a new record minimum for the date and the lowest for so late in the season.

7-9

In 1913…heavy snowfall totaled 10.9 inches in downtown Denver behind a cold front. Most of the snow fell on the 8th. Northeast winds were sustained to 35 mph with gusts to 38 mph on the 9th.

In 1935…moderate dust blew into the city around 9:00 pm on the 7th and persisted until early afternoon on the 9th. Southeast winds were sustained to around 20 mph on the 7th and 8th. Winds shifting to the west at sustained speeds to 20 mph cleared the dust from the air on the 9th.

7-12

In 1959…snow falling over a 5-day period totaled 20 to 30 inches just east of the mountains…while over the plains blizzard conditions closed schools and blocked highways. The second big storm in two weeks dumped 16.4 inches of snowfall on Stapleton Airport with the most…11.6 inches… Occurring on the 8th. East winds gusted to 37 mph on the 9th. Temperatures dipped into the single digits on the mornings of the 7th and 12th when 7 degrees were registered. Low temperature records for the dates were set on the 9th…10th…and 12th. The cold temperatures caused streets to glaze with ice…resulting in the death of a pedestrian who was struck by a car in Denver. Three people died from heart attacks while shoveling the heavy… Wet snow.

8

In 1885…dense smoke polluted the air until noon.

In 1887…south winds were sustained to 42 mph.

In 1890…northwest winds were sustained to 48 mph with gusts as high as 60 mph.

In 2005…a mixture of strong pressure gradient winds coupled with thunderstorm outflow winds produced high winds across metro Denver. The high winds downed power lines and knocked out electricity to about 19 thousand customers on the east side of metro Denver. High wind reports included gusts to 68 mph in Longmont…61 mph near Castle Rock…59 mph at Centennial Airport…and 54 mph at Denver International Airport.

8-10

In 1999…a windstorm caused 20 million dollars in damage along the Front Range urban corridor from Fort Collins south to Pueblo and to the east over the plains…making the storm equal to the costliest windstorm ever…which occurred in Boulder on January 17…1982. In metro Denver… Several homes were damaged as shingles were blown off roofs. Large pieces of a roof torn off a strip mall in Lakewood damaged several cars in a parking lot. Most of the damage to homes consisted of broken fences…awnings…doors…and windows. Scores of automobiles suffered broken or cracked windshields and paint damage from flying debris. Multiple accidents were triggered as several tractor-trailer rigs were blown on their sides by the strong cross-winds. Blowing dust and dirt caused near zero visibilities at times. Both I-25 and I-76 were closed north and northeast of Denver. State Highway 93 was closed between Golden and Boulder. Several trees…power poles…and power lines were downed…causing a number of outages as well as sparking a few small grass fires. Highest wind gusts reached 112 mph atop Niwot Ridge near the Continental Divide west of Boulder…102 mph at Wondervu…100 mph at the National Center for Atmospheric Research mesa lab in Boulder…98 mph at the national wind technology center near Broomfield…96 mph on Rocky Flats…92 mph at Jefferson County Airport near Broomfield and on the University of Colorado campus in Boulder…and 90 mph at Highlands Ranch in southwest metro Denver. Winds gusted to 48 mph at Denver International Airport.

9

In 1950…strong southwest winds gusting to 58 mph reduced the visibility to 1 mile in blowing dust at Stapleton Airport. Scattered minor wind damage…consisting of falling tree branches and damage to signs…occurred across metro Denver.

In 1989…6 to 12 inches of snow fell at many locations in the Front Range foothills. Boulder received 6 to 8 inches. Five inches (5.0 inches) of snow fell at Stapleton International Airport…causing 2 hour flight delays. I-25 south of Denver was closed for 4 hours due to a 100- car traffic pileup. North winds gusted to 33 mph at Stapleton International Airport where the maximum snow depth on the ground was only 3 inches due to melting.

Continue reading April 8 to April 14 – This Week in Denver Weather History →

Thornton Weather

City of Thornton announces emergency alert system for residents

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City of Thornton Emergency Management T-Alerts
The City of Thornton's new Emergency Management T-Alerts will inform residents of a wide variety of weather and civil emergencies.

Sitting at the western edge of tornado alley, the Denver metro area is home to severe weather of all forms.  In an effort to keep residents aware of the dangers Mother Nature brings every year, the City of Thornton is set to roll out an email alert system.

It has been nearly 31 years since the most destructive tornado to strike the Denver area tore through the city of Thornton.  In the intervening time between now and then, it is ironic that neither Thornton nor Adams County deployed any sort of alert system for its residents beyond Reverse 911.

Seeking to correct that lapse, Thornton’s Office of Emergency Management presented a significant enhancement to the city’s T-Alert system to city council at a planning session last night.

T-Alert is the existing email subscription system for Thornton residents that can keep them up to date with everything from traffic to trash services to recreational opportunities.  Now, emergency management announcements will be added to the service.

Emergency Manager Gene Putman explained that with the proliferation of email on mobile devices like cellular phones, the system will allow the city to send out warnings to residents in a matter of seconds.  The system was tested during the February snowstorms and was a resounding success.

Dispatches can be sent out by the city’s emergency management personnel or in an urgent situation, the new 911 center.  Spanish translations to the messages will also be included in the emails.

Putman said, “Within 30 seconds of a warning being issued by the National Weather Service we can have that critical information out to residents.”

Uses for the emergency management service will include obvious items such as tornado watches and warnings and severe hail or flooding.  Also thrown into the mix will be important announcements about major snow events, hazardous material spills and other types of civil alerts.

Jack Ethredge, City Manager, is no stranger to disasters having served as Emergency Manager along the Gulf Coast during two hurricanes.  He told council the system gives the city an “important, broader way to communicate.”

While the new system will help to keep residents safe, officials also remind residents that they must take responsibility for their own safety as well and stay aware of developing weather.  Local news media should be monitored and residents should own a NOAA All Hazards Radio.

  • Note: In addition to the city’s alert system, you can subscribe to ThorntonWeather.com’s alert system.  We believe the two systems will complement each other.  Our system provides all watches and warnings from the National Weather Service while the city’s will maintain a focus on the major events.

Thornton also continues to improve and refine its disaster preparedness as a city government.

Emergency management personnel are receiving important training on disaster response and new emergency procedures are being developed all city employees.

When disaster strikes, the speed and accuracy of a response is essential and Emergency Investigation Area Teams have been created to aid on this front.  Each team will be comprised of personnel from key city departments.  These teams will be responsible for one of six Emergency Investigation Areas and when needed, will be deployed to document a situation and provide direction.

Thornton Weather

March 2012 goes into the Denver weather history books on a number of marks

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Record setting high temperatures in Thornton.
March 2012 goes into the history books as the driest, least snowiest and 2nd warmest March on record in Denver.

The month of March in Denver is typically known for its snow and corresponding chilly temperatures.  That however was certainly not the case for March 2012 as the Mile High City saw one of its warmest and driest Marches on record.

From the start of the month to the end, March’s temperatures were well above normal.  While we would normally see days with temperatures in the 50s, we instead saw 70s and even a couple of 80+ degree days.

The historical overall average temperature for the month of March is 40.4 degrees (based on 1981 to 2010 normals).  March 2012’s average of 49.2 degrees was an astonishing 8.8 degrees above normal.

This sends the month into the record books as the second warmest March ever recorded in Denver.  The number one spot is held by March 1910 which saw an average of 50.4 degrees.

Here in Thornton, we were actually slightly warmer than the official Denver measuring station at DIA.  Our monthly average temperature came in at 49.6 degrees.

Individually, six days set or tied high temperature records for Denver:

  • 74 degrees on March 13 which tied the old record of 74 set in 2007 and previous years
  • 75 degrees on March 16 which broke the old record of 74 set just one year ago in 2011
  • 76 degrees on March 17 which broke the old record of 75 set in 1974
  • 76 degrees on March 23 which tied the old record of 76 set in 1967
  • 75 degrees on March 25 which tied the old record of 75 set in 1998 and previous years
  • 81 degrees on March 31 which broke the old record of 80 set in 1946

In terms of precipitation, March 2012 will now hold the marks for the driest and least snowiest on record.

The rain bucket at Denver International Airport saw a mere 0.03 inch of liquid precipitation.  This was far below the average of 0.92 inch and easily puts March 2012 into the books as the number one driest March on record.  The previous record holder was 1908 when 0.11 inch was recorded.

March is historically Denver’s snowiest month averaging 10.7 inches.  This year the month only brought a trace of snow on three days.  The previous least snowiest March occurred in 1883 when 0.3 inch of the white stuff was recorded.

Just like Denver, Thornton saw an extraordinary lack of snow and precipitation.  We as well recorded 0.03 inch of precipitation but we did manage to record 0.40 inch of snow, all on the morning of the 2nd.

Click here to view the March 2012 climate summary for Thornton.

CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
1026 AM MDT SUN APR 1 2012

................................... 

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF MARCH 2012... 

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2012

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................ 
TEMPERATURE (F)
RECORD
 HIGH              84   03/26/1971
 LOW              -11   03/28/1886
HIGHEST            81   03/31        84      -3       76  03/21
LOWEST             16   03/02       -11      27       14  03/05
AVG. MAXIMUM     65.5              54.4    11.1     58.7
AVG. MINIMUM     32.9              26.4     6.5     27.8
MEAN             49.2              40.4     8.8     43.3
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      0               1.9    -1.9        1
DAYS MIN <= 32     14              23.6    -9.6       24
DAYS MIN <= 0       0               0.1    -0.1        0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         4.56   1983
 MINIMUM         0.11   1908
TOTALS           0.03R             0.92   -0.89     0.35
DAILY AVG.       0.00              0.03   -0.03     0.01
DAYS >= .01         2               5.9    -3.9        8
DAYS >= .10         0               2.4    -2.4        1
DAYS >= .50         0               0.3    -0.3        0
DAYS >= 1.00        0               0.1    -0.1        0
GREATEST
 24 HR. TOTAL    0.03   03/01 TO 03/02           03/28 TO 03/28
                                                          03/28 TO 03/28
                                                          03/28 TO 03/28
 STORM TOTAL       MM                                 MM
 (MM/DD(HH))            MM                    03/28(00) TO 03/28(00)
                                                 03/28(00) TO 03/28(00)8
                                                 03/28(00) TO 03/28(00)8

SNOWFALL (INCHES)
RECORDS
 TOTAL             MM   5
TOTALS              T               11.7

DEGREE_DAYS
HEATING TOTAL     483               763    -280      666
 SINCE 7/1       4863              5202    -339     4817
COOLING TOTAL       0                 0       0        0
 SINCE 1/1          0                 0       0        0

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
......................................................... 

WIND (MPH)
AVERAGE WIND SPEED              11.5
RESULTANT WIND SPEED/DIRECTION   5/203
HIGHEST WIND SPEED/DIRECTION    46/180    DATE  03/18
HIGHEST GUST SPEED/DIRECTION    58/190    DATE  03/18

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.50
NUMBER OF DAYS FAIR            9
NUMBER OF DAYS PC             20
NUMBER OF DAYS CLOUDY          2

AVERAGE RH (PERCENT)     34

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       0
LIGHT RAIN                0     FREEZING RAIN              0
LT FREEZING RAIN          1     HAIL                       0
HEAVY SNOW                0     SNOW                       0
LIGHT SNOW                2     SLEET                      0
FOG                       2     FOG W/VIS <= 1/4 MILE      0
HAZE                      3

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

$$
Weather History

April 1 to April 7 – This Week in Denver Weather History

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This Week In Denver Weather History
April 1 to April 7 - This Week in Denver Weather History

April in the Denver area can offer up an extraordinary array of weather conditions. As we discussed in our April weather preview, everything from wind and snow to thunderstorms and tornadoes can make an appearance. We see this variety in our look back at this week in Denver weather history which includes all of those conditions and more.

From the National Weather Service:

31-1

In 1876…heavy snow began during the night and lasted all day on the 31st and through the morning of the 1st. The average depth of snow fall was 10 to 12 inches…but strong winds whipped the snow into drifts of 8 to 10 feet deep on the streets of the city. Precipitation from the storm was 1.03 inches on the 31st and 0.37 inch on the 1st.

In 1891…heavy moist snowfall totaled 18.0 inches in the city. Northeast winds were sustained to 20 mph with gusts to 24 mph on the 31st.

In 1936…northeast winds sustained to 21 mph produced a light dust storm in the city.

In 1975…a major storm dumped 9.3 inches of snowfall at Stapleton International Airport where northwest winds gusted to 41 mph. Rain changed to snow on the afternoon of the 31st…reducing the visibility to as low as 1/8 mile. Snow continued all day on the 1st and accumulated to a depth of 8 inches on the ground. The minimum temperature of 10 degrees on the 1st set a new record low for the date.

31-2

In 1980…the second major blizzard in 5 days buried much of eastern Colorado under 6 to 12 inches of snow. Some drifts were up to 22 feet high. Hundreds of travelers were stranded. Over 3000 families were without power. Livestock losses were high. Metro Denver escaped the main brunt of this storm. At Stapleton International Airport…only 6.3 inches of snow fell over the 3-day period and north winds gusted to only 22 mph on the 1st.

31-3

In 1979…total snowfall of 6.6 inches was measured at Stapleton International Airport where north winds gusted to 31 mph on the 31st. The greatest accumulation of snow on the ground was 3 inches on the 1st.

31-4

In 1905…much rain and some snow occurred over the 5 days behind an apparent cold front. Precipitation totaled 2.00 inches. There was a thunderstorm on the 3rd. Snowfall totaled 3.0 inches on the 4th. North winds were sustained to 34 mph on the 1st and 2nd and to 30 mph on the 3rd. High temperatures during the period ranged from the upper 30’s to the lower 40’s. Low temperatures were in the upper 20’s and lower 30’s.

1

In 1987…a vigorous cold front produced 2.3 inches of snowfall at Stapleton International Airport where northeast winds gusted to 39 mph. The temperature dropped from a maximum of 59 degrees at mid-morning to a low of 25 degrees at midnight.

1-2

In 1963…strong winds buffeted metro Denver…while wind- whipped fires consumed grassland on the plains. A child was injured by a windblown falling tree in Castle Rock. Southwest winds gusted to 52 mph at Stapleton Airport… Causing some blowing dust. The worst fire storm burned over 25 thousand acres of grazing land in southern Weld County near Roggen northeast of Denver.

In 1984…a snowstorm with near-blizzard conditions over eastern Colorado closed many roads…including I-70 and I-76 east of Denver and I-25 between Denver and Colorado Springs. At Stapleton International Airport…snowfall totaled only 2.5 inches…but north winds gusted to 45 mph on the 2nd.

In 1999…moist upslope conditions allowed heavy snow to develop in the Front Range foothills where snowfall totals included: 10 inches at aspen park and Evergreen; 9 inches at turkey creek; 8 inches at Idaho Springs and Genesee; 7 inches at Aspen Springs…Crow Hill…Intercanyon…and Lake George.

In metro Denver snowfall totals included: 10 inches south of Sedalia; 8 inches in Littleton; 7 inches at Morrison; 6 inches at Highlands Ranch; and 4 to 5 inches in Northglenn…Parker and near Louisville. Snowfall totaled 4.7 inches at the site of the former Stapleton International Airport.

1-3

In 1945…snow fell across metro Denver for a total of 51 consecutive hours. While the storm was not accompanied by excessive snow…the long duration made the event a heavy snow producer. Snowfall totaled 10.7 inches in downtown Denver with 9.5 inches recorded at Stapleton Airport. North winds were sustained to 21 mph on the 1st; otherwise winds were not strong. The air mass was very cold for April. The high temperatures of 26 on the 2nd and 17 on the 3rd were record low maximums for the dates. The latter was also a record low maximum for the month. Warm weather following the storm quickly melted the snow.

In 1973…heavy snow fell at Stapleton International Airport where 8.7 inches were measured. Snow began late on the 1st and continued through early morning on the 3rd. Thunder accompanied the snow during the late morning and afternoon of the 2nd. North winds gusted to 33 mph on the 2nd and 37 mph on the 3rd. Snow only accumulated to a depth of 5 inches on the ground due to melting.

In 1977 a foot of snow fell in Boulder and Broomfield. The Denver-Boulder turnpike was closed for an hour after numerous minor traffic accidents. At Stapleton International Airport…snowfall totaled 4.7 inches and southeast winds gusted to 32 mph on the 2nd. The greatest depth of snow on the ground was only 3 inches due to melting.

Continue reading April 1 to April 7 – This Week in Denver Weather History →

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