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.

6

In 1876…heavy snow fell during the night and ended during the morning…but no amount was recorded. Light hail fell briefly during the late afternoon. Precipitation for the day totaled 1.05 inch which would give an estimated snowfall of nearly 11 inches had all of the precipitation been snow.

In 1889…northwest winds were sustained to 45 mph in the city.

In 1893…heavy snow of 8.9 inches fell over downtown Denver. Once on the ground…the snow melted rapidly. This was the only snow of the month. Northwest winds were sustained to 20 mph.

In 1904…west winds were sustained to 45 mph with an extreme velocity to 46 mph.

In 1914…an apparent dry microburst produced sustained north winds to 44 mph with gusts as high as 50 mph.

In 1920…a thunderstorm produced hail and 0.55 inch of rain. The hail of unknown size covered the ground.

In 1921…thunderstorm winds were sustained to 42 mph with gusts to 44 mph. Rainfall was only 0.17 inch.

In 1936…a light to moderate duststorm moved in from the east on southeast winds and lasted most of the day. The dust reduced the visibility to two miles at times. Winds from the northwest sustained to 21 mph swept the dust out of the city during the late afternoon.

In 1966…a funnel cloud was sighted for 7 minutes to the southwest of Stapleton International Airport. The funnel appeared to be picking up dust from the ground…but was too distant to tell. No damage was reported.

In 1968…a thunderstorm wind gust to 53 mph was recorded at Stapleton International Airport.

In 1988…high winds raked the state. Wind gusts ranged from 60 to 80 mph in Boulder…Aurora…and at Centennial Airport. South-southwest winds to 53 mph were recorded at Stapleton International Airport. Across metro Denver…the strong winds knocked windows out of buildings…downed power poles and wires and some fences…unroofed several buildings…and damaged signs.

In 1997…strong winds from a dry microburst blew an empty 18-wheeler on its side in the northbound lane of I-25 north of Denver near the Brighton exit. There were no injuries. West winds gusted to 46 mph at Denver International Airport.

In 2017…lightning struck dangerously close to a woman while she watched a youth baseball game. She felt her legs go numb after a lightning bolt struck the ground.

6-7

In 1873…snowfall totaled 8.9 inches in downtown Denver. Most of the snow fell on the 6th.

7

In 1904…west winds were sustained to 48 mph with gusts to 60 mph. A shower produced 0.16 inch of rain.

In 1953…a microburst caused a brief wind gust to 58 mph at Stapleton Airport.

In 1958…3/4 inch diameter hail fell over south metro Denver… 10 miles southwest of Stapleton Airport.

In 1977…baseball size hail damaged windows in Wheat Ridge. Hail was 4 inches deep on the ground in Arvada. Hail 3/4 to 1 inch diameter fell in Westminster and Kittredge.

In 1990…a fast moving cold front produced wind gusts of 40 to 60 mph. Brighton reported a wind gust to 57 mph…while north wind gusts to 44 mph were measured at Stapleton International Airport.

In 1995…severe thunderstorms struck Aurora. Hail piled 4 to 5 inches deep in the vicinity of Quincy Reservoir in south Aurora. Lightning struck an Aurora police communications tower causing significant malfunction to the primary system. Minor damage was sustained when lightning struck an apartment building. Hail…up to 1 1/4 inches in diameter…while soft and slushy…accumulated up to 6 inches deep in 15 minutes. Many streets were closed for an hour or more due to flooding caused by heavy rain and melting hail stones. Some trees were stripped of their leaves. Hail as large as 1/2 inch diameter was measured at Denver International Airport where a funnel cloud was sighted.

In 2003…a tornado touched down briefly near Bennett…but did no reported damage.

In 2005…severe thunderstorms produced 3/4 inch hail near Brighton and a thunderstorm wind gust to 60 mph near Fort Lupton.

In 2014…severe thunderstorms produced large hail…from 1 to 1 1/2 inches in diameter…across parts of Arvada…Broomfield… Dacono…Northglenn and Thornton.

In 2015…a severe thunderstorm produced hail…up to walnut size…in Elbert County. A weak tornado touched down briefly near Ft. Lupton.

In 2017…a 37-year-old woman and her horse were killed near Sedalia after lightning hit a nearby tree. A teenage girl was also seriously injured. Damaging microburst winds downed trees and power poles across parts of Adams…Arapahoe…Denver and Douglas Counties. Electrical lines and branches were also snapped causing scattered power outages.

7-8

In 1958…rainfall totaled 2.50 inches at Stapleton Airport.

8

In 1873…a very light rain fell until 5:00 am…when it turned into light snow and sleet and was accompanied by brisk northeast winds. The snow froze as it fell… Breaking the telegraph lines in many places. Precipitation totaled only 0.14 inch in the city.

In 1883…a severe rain and hailstorm struck the city. In 25 minutes the hail was 5 inches deep in the vicinity of the weather office in downtown Denver and reported as deep as 10 to 12 inches in other parts of the city. Gutters were blocked by the hail…and many cellars were flooded. Precipitation from the storm was 1.90 inches with the total for the day recorded at 2.02 inches. The size of the hail was not recorded.

In 1988…a wind gust to 68 mph was recorded at Echo Lake. Northwest winds gusted to 35 mph at Stapleton Airport.

In 1995…high winds of unknown strength blew a camper shell from the back of a pickup truck near Fort Lupton. North winds gusted to 49 mph at Denver International Airport.

In 1996…1 to 2 inch diameter hail was measured in Lochbuie northeast of Denver. Bean size hail fell in Brighton. The large hail fell from severe thunderstorms to the northeast of metro Denver.

In 2003…tornadoes touched down briefly near Brighton… Watkins…and Strasburg…but did no reported damage. Hail to 3/4 inch in diameter was measured near Hudson.

In 2017…severe thunderstorms broke out across Denver and the surrounding metro area and produced large damaging hail…strong winds…heavy rain and flash flooding. Hail up to baseball size…caused extensive property damage to cars…homes and businesses across a large part of Denver and the western suburbs including Arvada…Lakewood and Wheat Ridge. According to the Rocky Mountain Insurance Agency Association…the storm was Colorados most expensive insured catastrophe…around $2.3 billion. The group estimated more than 150000 auto insurance claims and 50000 homeowner insurance claims would be filed. Businesses and homes sustained holes in siding along with broken windows and torn screens. Severe thunderstorm producing large hail…strong winds and heavy rain impacted areas around Greeley as well. The high cost incurred from the storm was due to a number of factors including: the size of the hail…the densely populated area…the time of day…the escalating costs to repair high-tech cars…and more expensive homes. Colorado Mills Mall in Lakewood was severely damaged after hail busted skylights and caused flooding inside stores. The common areas and tenant spaces suffered substantial water damage. Extensive damage to electrical systems…mechanical systems… including HVAC and lighting…were expected to keep the mall closed for several months. In Lakewood…the loss in sales tax was projected to be about $350000 per month…which was 3 to 4 percent of the city`s monthly budget. Prestige Imports in Lakewood which sells Audis and Porches…250 to 300 vehicles were impacted by the storm. Some of those vehicles were valued at nearly $200000 each.  Significant damage was reported at Lutheran Medical Center after the hailstorm tore through Wheat Ridge. The hospital building and some of the medical office buildings sustained broken windows. The storm also hit the office of the Colorado Bureau of Investigation in Lakewood. The offices were flooded…several cubicles destroyed…and even some ceiling tiles fell off. The storm damage prompted school officials to close all thirteen Adams 12 Five Star schools in Commerce City and Beach Court Elementary school in Denver. Most of the schools in the Adams 12 Five Star District were at least 50 years old and sustained flood damage. Large hail damaged an apartment building near Regis University… shattered windows and punctured the siding on the west- facing side of the building. Hail and heavy rain clogged drains and caused flash flooding throughout Greeley. Up to three feet of water covered the roadway near U.S. 34 and U.S. 85. Greeley firefighters helped several residents get out of garden level apartments that had flooded. Several other businesses and buildings suffered flood damage… including Greeley City Hall and an apartment complex in Evans. The Greeley Mall was extensively damaged when water poured into the mall from the roof and debris inundated the main floor.

8-9

In 1957…intense heavy rain caused flash flooding on toll gate creek in Aurora where 3 people were killed in a car. Up to 4 inches of rain fell in 5 hours in the toll gate creek basin. The rain also caused flash flooding on sand creek in Aurora and Denver. Rainfall totaled 3.29 inches at Stapleton Airport with most of the rain…2.34 inches… Occurring on the 9th.

8-10

In 1979…4.3 inches of snow fell at Stapleton International Airport where northwest winds gusted to 30 mph on the 8th. Most of the snowfall…2.3 inches…occurred on the 9th. High temperature of only 35 degrees on the 9th equaled the record low maximum for the date.

9

In 1875…a heavy windstorm swept across the city for most of the day. West-northwest winds averaged a sustained speed of 31 mph between 6:00 am and 3:00 pm. The peak wind was sustained to 45 mph at 9:50 am.

In 1918…post-frontal winds were sustained to 40 mph with gusts as high as 43 mph. Only a trace of rain fell.

In 1941…a tornado was noted at 2:20 pm to the northeast of downtown and was followed by another similar shaped cloud or dust roll estimated 3 miles behind. Thick dust followed with heavy gusts of wind. The temperature fell 15 degrees in 10 minutes following the twister. The mild tornado did little damage except to unprotected frame structures. Winds were sustained to 50 mph with the passing of the tornado at Stapleton Airport. It was visible to observers for 10 minutes and was lost from sight as it traveled east into huge rolls of dust. Hail and rain followed with a few hailstones as large as 1/2 inch in diameter downtown. No damage was reported from the hail. Thunderstorm winds sustained to 31 mph produced blowing dust downtown. Precipitation was only 0.07 inch.

In 1983…streams swollen by recent rain and snowmelt caused an earthen dam to collapse…washing out portions of State Highway 67 near Deckers in southern Douglas County.

In 1992…three boys…ages 11…12…and 16…were struck by lightning while taking cover under a large tree during a thunderstorm in Jefferson County…just 7 miles northwest of Denver. The three were seriously injured.

9-10

In 1889…heavy rainfall totaled 2.15 inches in downtown Denver. The cold rain was mixed with snow at times overnight. Temperatures on the 10th ranged from a high of 38 degrees to a low of 32 degrees with north winds sustained to 22 mph.

In 2003…a late spring snowstorm hammered the mountains… Eastern foothills…and urban corridor. The heaviest snowfall occurred north of interstate 70. The heavy wet snow caused damage to trees throughout metro Denver and downed power lines. About 40 thousand people along the urban corridor were without power. Storm total snowfall amounts included: 11.5 inches in Louisville… 8 inches in Boulder and Broomfield; 7 inches in Thornton…Broomfield…at Denver International Airport… And at the site of the former Stapleton International Airport; and 6 inches 4 miles east of Denver. Snowfall ranged from 4 to 9 inches across extreme southern weld County. In the foothills…15 inches of snow fell near Jamestown…9 inches at Rollinsville and Rawah…with 8 inches at Chief Hosa and atop Lookout Mountain. The snow was accompanied by thunder on the afternoon of the 9th at Denver International Airport where west winds gusted to 25 mph on the 9th and north winds gusted to 22 mph on the 10th.

In 2015…from the 9th to the 10th…a strong storm system brought heavy snow to areas in and around Denver. Moderate to heavy rain showers transitioned over to snow by early in the evening on the 9th. Heavy wet snow overnight caused many trees to break under the pressure of the sudden weight. Tree damage ranged from minor to significant…with old growth trees losing large limbs and new trees sustaining fatal damage. Power outages affected about 43350 Xcel Energy customers in metro Denver. The Intermountain Rural Electric Association also reported about 1000 power outages in the Strasburg areas. In the high country…CDOT shut down Interstate 70 between the Eisenhower Tunnel and Silverthorne due to multiple crashes.

10

In 1875…a windstorm sand-blasted the city from 10:00 am until midnight. Northwest winds sustained to 60 mph brought clouds of sand…which caused high damage to unfinished buildings.

In 1912…a vigorous cold front produced strong north winds and rain. North winds were sustained to 48 mph with gusts as high as 60 mph. Rainfall totaled 1.10 inch.

In 1935…no precipitation occurred…making this one of only two days without precipitation during the entire month. The other day was the 21st. Precipitation totaled 4.95 inches for the month.

In 1956…northwest winds gusted to 53 mph at Stapleton Airport where the visibility was briefly reduced to 1/2 mile in blowing dust.

In 1974…strong winds caused 30 thousand dollars in damage to a building under construction in Lakewood. Microburst winds gusted to 46 mph at Stapleton International Airport.

In 1988…lightning struck a house in Boulder…setting it afire. The house…valued at 170 thousand dollars…was a total loss.

In 1989…golf ball size hail fell over southeast Denver near the junction of I-25 and I-225. Hail to 3/4 inch in diameter fell over southeast Aurora. Only 3/8 inch hail fell at Stapleton International Airport.

In 1991…high winds up to 63 mph raked the eastern foothills. Winds estimated to 50 mph tore a roof from a home in Lafayette. A tower at Jefferson County stadium in west metro Denver was blown over by the high winds. No injuries were reported. Southeast winds gusting to 48 mph at Stapleton International Airport produced some blowing dust. The temperature climbed to a high of 86 degrees… Equaling the record maximum for the date.

In 2005…severe thunderstorms produced hail as large as 2 inches in diameter in and near Longmont.

In 2023…severe thunderstorms produced large hail across to the eastern and southern portions of the Denver metropolitan area. The hail ranged in size from 1 to 1 3/4 inches in diameter. One storm developed over south Denver… while the rest formed along a line the stretched from Buckley AFB to between Lone Tree and Parker.

10-11

In 1918…post-frontal snowfall totaled 4.7 inches in downtown Denver. Northwest winds gusted to 19 mph on the 10th.

In 1923…winds were strong and gusty on both days. Northwest winds were sustained to 40 mph with gusts to 44 mph on the 10th. North winds were sustained to 39 mph with gusts to 46 mph behind an apparent cold front on the 11th.

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.

11

In 1879…an apparent cold front during the afternoon produced sustained north winds as high as 60 mph and great clouds of blowing dust. The dust filled the air until the thunderstorm rain began…which produced 1.46 inches of rainfall. The rain ended during the evening.

In 1900…southwest winds were sustained to 40 mph with gusts to 46 mph.

In 1958…a microburst caused a brief wind gust to 55 mph at Stapleton Airport.

In 1963…south-southwest winds gusted to 48 mph at Stapleton Airport. Winds May have been stronger over west Denver where some buildings were damaged.

In 1998…large hail fell over south metro Denver. Hail as large as 1 1/4 inches in diameter was measured in Parker with 1 inch hail recorded in Littleton and 4 miles south of Lakewood in Jefferson County. Hail to 3/4 inch diameter was measured in Douglas County…11 miles west- northwest of Parker.

11-12

In 2014…from the 11th to the 12th…a strong storm system moved from southwest Colorado and produced heavy snow in and near the Front Range Foothills and metro Denver. The snow was heaviest in the foothills where up to 2 1/2 feet of snow was observed. In the foothills…storm totals included: 30 inches near Pinecliffe; 29 inches… 8 miles northeast of Four Corners; 28 inches near Pingree Park; 27 inches near Allenspark; 20.5 inches near Idaho Springs; 19.5 inches at Gold Hill; 19 inches near Genesee; 18 inches near Blackhawk; 17 inches at Aspen Springs; 16.5 inches near Ward; 13.5 inches at Bergen Park; with 11 inches at Evergreen. Along Urban Corridor and Palmer Divide…storm totals included: 10.5 inches at Eldorado Springs; 10 inches at Ken Caryl; 9 inches at Superior; 8 inches near Morrison; 7.5 inches in Broomfield and Highlands Ranch; 7 inches in Denver… near Franktown…Golden…Lakewood and Highlands Ranch; 6 inches…5 miles northeast of Westminster…7 miles south of Lyons and near Parker; with 5.5 inches at Aurora. At Denver International Airport…1.1 inches of snowfall was observed… along with 0.9 inches of water.