Severe weather takes to the forefront in our look back at this week in Denver weather history. We see many historical flooding events that were commonplace in the late 19th / early 20th century before controls were put in place. Almost everyone will recall the Windsor tornado, an EF3 monster that struck the town five years ago.

From the National Weather Service:

18-19

In 2011…a severe thunderstorm in central Adams County produced large hail and heavy rainfall on the 18th. Large hail from 1 inch to 1 3/4 inches in diameter…was reported in Commerce City…2 miles south-southeast of federal heights…Northglenn…and 2 miles south of Thornton.

In Commerce City…the storm uprooted trees and knocked out power lines. A carport was lifted off the ground and struck the power lines overhead. Heavy rain…from 1.0 to 1.5 inches fell in less than 2 hours in Commerce City and near Brighton. The combination of hail and strong winds broke windows in Northglenn.

In the foothills…moderate to heavy snow showers developed overnight. Storm totals included: 10.5 inches at Gold Hill…9.5 inches…3 miles west of Jamestown; 9 inches at Lake Eldora; with 6 inches… 11 miles southwest of Gilpin and 4 miles east-northeast of Nederland. At Denver International Airport…total rainfall over the 2-day period totaled 1.71 inches.

In addition…a peak wind gust to 37 mph was recorded on the 18th.

18-20

In 1915…3.9 inches of snow fell in the city. The estimated amount of snow that melted as it fell was 6.2 inches which would have totaled an estimated 10.1 inches of snowfall. Precipitation totaled 1.03 inches. North winds were sustained to 32 mph on the 18th. Low temperatures dipped to 25 degrees on both the 18th and 20th…establishing record minimums for both dates.

In 1988…prolonged heavy rainfall drenched metro Denver. The event began when heavy thunderstorms on the 18th caused some street flooding and power outages…followed by steady rain on the 19th and 20th. Rain amounts across metro Denver totaled 3 to 4 inches. Rainfall totaled 3.71 inches at Stapleton International Airport where north winds gusted to 39 mph on the 20th. Four to eight inches of snow fell in the foothills above 7 thousand feet.

19

In 1927…southeast winds were sustained to 40 mph with gusts to 44 mph.

In 1956…a thunderstorm wind gust to 54 mph was recorded at Stapleton International Airport.

In 1969…hail stones to 1 inch in diameter were measured in Arvada and Aurora. Some minor damage was reported. Pea to marble size hail fell in Westminster.

In 1972…a tornado was reported by aircraft about 5 to 10 miles east of Parker.

In 1988…lightning started a fire at a house in the Denver suburb of greenwood village…causing 2 thousand dollars in damage.

In 1991…strong thunderstorms over east metro Denver produced wind gusts of 56 to 60 mph. The strong winds downed power lines…trees…and fences at some locations in Aurora. Thunderstorm outflow winds gusted to 60 mph at Stapleton International Airport.

In 1994…severe thunderstorms rumbled across metro Denver. The storms produced wind gusts averaging 65 mph and hail up to dime size. Wind gusts to 77 mph were recorded in Brighton. Numerous trees and power poles were downed by the winds. One power pole fell onto spectators at a high school graduation ceremony in Commerce City…injuring 6 people. In Fort Lupton…trees fell onto 2 parked cars… Knocking out the windshields. Hail to 3/4 inch in diameter was reported in Littleton. A thunderstorm wind gust to 52 mph was recorded at Stapleton International Airport.

In 1995…a slow moving tornado…which was mainly discernible by its dust and debris cloud…was spotted 2 miles northeast of Denver International Airport or about 10 miles northwest of Bennett. No damage was reported.

In 2007…lightning struck a 33-ft statue of Jesus at Mother Cabrini Shrine…in the foothills west of Golden. The blast broke off one of the statue’s arms and a hand…and also damaged a foot. It cost an estimated $200000 to repair.

In 2009…lightning struck the roof of a residence in Highlands Ranch. The home was not a total loss…but the fire caused extensive damage.

In 2010…a thunderstorm produced hail up to 7/8 inch in diameter in Thornton.

19-20

In 1864…a devastating major flash flood occurred on the normally dry and sandy Cherry Creek in Denver. The flood was caused by heavy thunderstorm rainfall and hail over the palmer ridge to the south of the city in both the Cherry Creek and plum creek basins. Nineteen deaths occurred along the South Platte River and Cherry Creek in Denver. The torrent swept cattle and sheep along with large trees and houses before it washing out several bridges…and moving large structures from their foundations. All city records were destroyed when city hall washed away. The rocky mountain news building…built on stilts in the middle of the creek…was totally destroyed by the raging waters…which were as deep as 5 feet on the morning of the 20th. Once the flood waters receded…much sand and gravel was left behind. Property damage from the flood was estimated at nearly one million dollars. This was the first major flood of record in the city.

Continue reading May 19 to May 25: This Week in Denver Weather History →

The snow is gone – almost – but as our look back at this week in Denver weather history shows, it could return. That however is unlikely and more typical spring severe weather is far more common.

From the National Weather Service:

10-12

In 2011…a spring snowstorm brought heavy snow to the Front Range foothills and Palmer Divide. Storm totals included: 18 inches…4 miles south-southeast of Pinecliffe; 16 inches in Coal Creek Canyon; 15 inches…4 miles west-southwest of Eldorado Springs; 13 inches at Gold Hill…12 inches…4 miles west-southwest of Conifer and 4 miles northwest of Elizabeth; 11.5 inches…6 miles southwest of Evergreen and 4 miles east-northeast of Nederland; 11 inches…3 miles east of Jamestown and 10.5 inches…3 miles east of Franktown and 3 miles south of Golden and 10 inches…10 miles north of Elizabeth. At Denver International Airport… 1 inch of snowfall was observed.

12

In 1875…two forest fires on the eastern slope of the foothills were visible from the city.

In 1904…north winds were sustained to 40 mph with gusts to 48 mph.

In 1950…brilliant and complete primary and secondary rainbows arching across the sky were observed from Stapleton Airport.

In 1951…a wind gust to 51 mph was recorded at Stapleton Airport.

In 1984…winds gusted to 69 mph in Boulder. Northwest winds gusted to 47 mph at Stapleton International Airport.

In 1987…a small weak tornado touched down for about 2 minutes in southeast Denver. The twister hit a car dealership…blowing about a dozen windows out of cars and shattering four skylights on the building. Some tin roofing was blown off a patio a block and a half away. The tornado also downed a power pole. Damage at the dealership was estimated at 10 thousand dollars. A man was slightly injured by lightning in northwest Aurora.

In 1995…several funnel clouds were sighted near Parker. One of the funnels produced a short-lived debris cloud on the ground in an open field. No damage was reported.

12-13

In 1907…the temperature warmed to a high of 73 degrees on the 12th…before a cold front produced a thunderstorm… Northeast winds sustained to 40 mph…and rain changing to light snow overnight. Snowfall totaled only 2 inches…but the high temperature on the 13th was only 39 degrees.

In 1961…a storm that covered metro Denver with rain and snow started as thunderstorms on the evening of the 12th. Hail to 1 1/2 inches in diameter was reported 10 miles northwest of Stapleton Airport. Rain continued overnight and changed to snow on the 13th. Snowfall totaled 6.4 inches and precipitation (rain and melted snow) 1.96 inches at Stapleton Airport where north winds gusted to 39 mph. The rain and heavy wet snow caused icing damage to utility lines. Heavy snow occurred in the foothills.

In 1982…a major storm dumped 1.50 to 3.50 inches of rain across northeast Colorado and deposited prodigious amounts of snow in the foothills. Coal Creek Canyon southwest of Boulder was buried under 46 inches of snow with 39 inches at Nederland. The heavy wet snow downed many power lines in the foothills. In Thornton…the roof of a school was damaged by water from the heavy rain. At Stapleton International Airport…1.49 inches of rain were measured over the two day period. The heavy rain ended a severe and prolonged drought.

In 2004…a winter storm produced heavy snow in excess of a foot in the foothills above 6 thousand feet while heavy rain fell across the city. The heaviest snow occurred in the high country of Boulder County. Storm total snowfall was 14.5 inches near Jamestown. Rainfall totaled 0.81 inch at Denver International Airport with 0.94 inch recorded at Denver Stapleton. A trace of snow was recorded at both locations. East winds gusted to 24 mph at Denver International Airport on the 12th.

13

In 1905…a thunderstorm produced hail during the late afternoon. Precipitation totaled 0.57 inch.

13-14

In 1912…heavy snowfall totaled 12.4 inches over the city. Most of the snow…9.9 inches…fell on the 13th…which was the greatest 24 hour snowfall in May at the time. This was the last snowfall of the season. The low temperature dipped to 27 degrees on the morning of the 14th.

In 1989…a spring storm brought heavy rain and snow to the foothills. Metro Denver was soaked with 1 to 2 inches of rain. Rainfall totaled 1.26 inches at Stapleton International Airport.

In the foothills…Echo Lake received 20 inches of snow. A 30-ton Boulder slid onto I-70 east of the Eisenhower Tunnel…closing the freeway for 2 hours.

Continue reading May 12 to May 18: This Week in Denver Weather History →

This time of year the focus is usually on spring severe weather with lightning, tornadoes and hail being the highlight. Our look back at this week in Denver weather history shows many of those types of events. Also notable are the few, unusually late in the season snow events, some of which were quite heavy.

From the National Weather Service:

1-5

In 1898…snowfall totaled 15.5 inches in downtown Denver. Most of the snow…6.2 inches…fell on the 3rd. Most of the snow melted as it fell. The greatest snow depth on the ground was only 2.5 inches on the 3rd at 8:00 pm. This was the only snowfall during the month. Northeast winds were sustained to 22 mph on the 1st.

2-5

In 2001…a very slow moving pacific storm system became parked near the four corners region…which allowed heavy snow to develop above 6500 feet in the foothills with a mix of rain and snow over lower elevations of metro Denver. Snowfall totals included: 21 inches atop Crow Hill and at Idaho Springs; 19 inches near Blackhawk; and 18 inches in Coal Creek Canyon…Genesee…and 11 miles southwest of Morrison. Snowfall totaled 6.2 inches at the site of the former Stapleton International Airport. Precipitation (rain and melted snow) totaled 2.09 inches at Denver International Airport where north winds gusted to 30 mph on the 2nd.

3-5

In 1908…rain changed to snow on the evening of the 3rd and continued through the early evening of the 5th. Snowfall totaled 10.0 inches over downtown Denver. This was the last measurable snow of the season. Precipitation totaled 1.51 inches. North winds were sustained to 23 mph on the 3rd…33 mph on the 4th…and 21 mph on the 5th. Three temperature records were set. High temperatures of 30 degrees on the 4th and 38 degrees on the 5th were record low maximum temperatures for the dates. The reading on the 4th was also the all-time record low maximum for the month of May.

In 2007…a slow moving pacific storm system…from the desert southwest…brought a period of unsettled weather to the region. During the 3-day period…locally heavy snow was reported over parts of the Front Range foothills. Storm totals included: 15 inches near Conifer…14.5 inches west of Jamestown…13.5 inches; 6 miles southwest of Evergreen…and 12.5 inches at pine junction. Severe thunderstorms…producing large hail…up to one inch in diameter were observed in the vicinity of Boulder and Hudson. Lightning struck a residence in Jefferson County. The roof was hit…causing the attic to catch fire. At Denver International Airport…lightning struck a United Airlines jet as it was pushing away from the gate. The passengers were taken off the jet and put on another plane.

4-5

In 1986…high winds buffeted the foothills. Wind speeds of 60 to 75 mph were recorded in Boulder. At Stapleton International Airport…west winds gusted to 45 mph on the 4th and to 40 mph on the 5th.

In 2000…a brief warm spell resulted in setting two daily high temperature records. The temperature climbed to highs of 87 degrees on the 4th and 89 degrees on the 5th.

4-8

In 1969…heavy rains caused flooding on Boulder creek in Boulder…which resulted in one death on the 7th. Flooding also occurred on bear creek in Sheridan and on the South Platte River in Denver. Rain over most of the eastern foothills started late on the 4th and continued with only brief interruptions in many areas until the morning of the 8th. Very high rates of rainfall occurred on the 6th and 7th with the greatest intensities in a band along the foothills from about 25 miles southwest of Denver northward to Estes Park. Storm totals by both official and unofficial measurements exceeded 10 inches over much of this area and were over 12 inches in some localities. Heavy snow fell in the higher mountains and in the foothills later in the period. The saturation of the soil resulted in numerous rock and landslides…and the heavy run-off caused severe damage along many streams and flooding on the South Platte River. Many foothill communities were isolated as highways were blocked and communications disrupted. Roads were severely damaged over a wide area…and a large number of bridges washed out. Many roads were closed due to the danger from falling rocks. A building in Georgetown collapsed from the weight of heavy wet snow. In Boulder…a man drowned when caught by the flooding waters of Boulder Creek…and a patrolman was injured. Rainfall totaled 7.60 inches in Boulder with 9.34 inches recorded at the Public Service Company electric plant in Boulder Canyon. In Morrison…rainfall totaled 11.27 inches in 4 days. Heavy rainfall totaled 4.68 inches at Stapleton International Airport over 3 days from the 5th through the 7th. Rainfall of 3.14 inches was recorded in 24 hours on the 6th and 7th. Downstream flooding continued along the South Platte River until the 12th when the flood crest reached the Nebraska line.

5

In 1903…apparent post-frontal northeast winds were sustained to 48 mph with gusts to 60 mph.

In 1950…a northwest wind gust to 52 mph was recorded at Stapleton Airport.

In 1969…a funnel cloud was observed for 2 to 3 minutes just north of Parker. Two other funnel clouds were sighted in the same area. The public sighted a tornado 15 miles east of Stapleton International Airport. No damage was reported.

5-6

In 1907…rain changed to snow on the 5th…continued through the night…and totaled 3.50 inches. Northeast winds were sustained to 15 mph on the 5th.

In 1917…post-frontal rain changed to heavy snow and totaled 12.5 inches over downtown Denver. Most of the snow… 12.0 inches…fell on the 5th and this was the greatest 24-hour snowfall ever measured during the month of May. This was also the only measurable snow of the month that year. Low temperatures of 27 degrees on the 5th and 23 degrees on the 6th were record minimums for the dates. High temperatures on both days were in the lower 40’s. Southeast winds were sustained to 24 mph with an extreme velocity to 26 mph.

In 1964…high winds gusted to 54 mph in Boulder and to 80 mph at Jefferson County Airport near Broomfield. Wind gusts of 50 to 60 mph were common over all of eastern Colorado. Buildings…power lines…trees…and vehicles were damaged by the wind. South-southwest wind gusts to 54 mph caused some blowing dust at Stapleton International Airport where the visibility was briefly reduced to 2 miles.

In 1973…a heavy driving rain storm with embedded thunderstorms…produced 1 to 5 inches of rain and caused local flash flooding along the east slopes of the Front Range. The greatest flash flooding occurred in metro Denver where rainfall totaled 3.56 inches at Stapleton International Airport. Flooding in metro Denver occurred on Clear Creek and the South Platte River…already swollen from heavy snowmelt. Numerous basements were flooded… Roads and streets were washed out…a bridge was demolished… And miscellaneous other damage was reported. North winds gusted to 39 mph at Stapleton International Airport during the storm. The storm produced major downstream flooding along the South Platte River all the way to the Nebraska border during the next two weeks. One person died and total damage was estimated at around 120 million dollars.

In 1978…heavy wet snow of around 24 inches collapsed an office and hotel building in Boulder. Many cars were abandoned in the city. Denver received 14 inches of heavy wet snow with Evergreen and Golden reporting 12 inches. Snowfall totaled 12.4 inches at Stapleton International Airport with a total accumulation of snow on the ground of 8 inches due to melting. Southeast winds gusted to 23 mph on the 5th. Temperatures both days remained in the lower to mid-30’s.

Continue reading May 5 to May 11: This Week in Denver Weather History →