Flash floods, the warmest summer on record and 15 tornadoes spawned in one day: Chicago's extreme weather during 2020
By Kori Rumore
What an intense year it was — in weather.
"What sticks out to us was that we experienced many extremes," Brett Borchardt, meteorologist for the National Weather Service's Chicago office, said after conferring with colleagues.
Examples of this ferocity include:
Significant lakeshore flooding due to record-high water levels in Lake Michigan;
May set a record for precipitation nearly two weeks before the month ended with flash floods and storms delivering a total of 9.15 inches of rain;
The summer, however, was dry and hot — the warmest on record with an average temperature nearly 5 degrees above average;
August's wind-driven derecho event was declared the costliest thunderstorm in U.S. history, spawning 15 tornadoes in northeast Illinois;
and it was historically warm — with seven consecutive days with temperature highs in the 70s — in November.
Here is how 2020 unfolded, meteorologically.
January: Flooding, warmth and airplane-produced snow
City worker Alonzo Owens takes pictures of waves crashing on East 73rd Street as his crew works to clear flooded South Shore Drive in Chicago on Jan. 11, 2020. (Zbigniew Bzdak/Chicago Tribune)
Jan. 11: Major lakeshore flooding and erosion due to near record-high water levels in Lake Michigan.
Jan. 17-18: Two to 5 inches of snow blankets the area.
Jan. 19: Meteorological winter (December-February) is, so far, one of the warmest on record.
Jan. 26: The conditions are just right for airplanes to produce snow over Chicago.
"It is not common for airplanes to induce snow, though it does happen under the right conditions. Provided sufficient moisture and a source of rising motion, snowflakes develop when the air temperature is below roughly -10 °C (14 °F). When the air temperature is close to but not below those temperatures, we instead end up with little water droplets that easily freeze when shaken up or disturbed, such as when a plane flies by. It's not easy to sustain these sorts of conditions for long periods of time. However, when they do occur, most areas actually see freezing drizzle (as those water droplets fall) and airplanes often experience icing as they fly through the cloud layer with the water droplets."
Brett Borchardt, National Weather Service meteorologist
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February: A record high to below zero
Snow frozen on the plants in Humboldt Park in Chicago as the snow keeps coming on Feb. 13, 2020. (Jose M. Osorio / Chicago Tribune)
Feb. 2: The sun returns after 11 consecutive days of clouds and the temperature reaches 52 degrees — a record high for the day — at O'Hare International Airport, the city's official recording site.
Feb. 14: The temperature at O'Hare airport drops to below zero for the first time this winter. It's also the coldest Valentine's Day morning in 77 years.
December-February: Chicago experiences its 14th warmest recorded winter.
March: More flooding and a little snow
The lakefront near 5000 South Lake Shore Drive in Chicago as the waves crash against the shoreline on a cold and windy March 6, 2020. (Jose M. Osorio/Chicago Tribune)
March 6: Significant lakeshore flooding.
Chris Corcoran, left, and Ed Keegan, both of Chicago, take in the view from 39th Street in Chicago as powerful waves are whipped up on Lake Michigan on March 6, 2020. (Terrence Antonio James / Chicago Tribune)
March 22-23: More than 2 inches of heavy, wet snow falls at O'Hare.
End of March: Monthly snowfall totals are below normal.
April: A dramatic hail event
Daffodils are weighed down by the snow in downtown Chicago as a mid-April snowfall blankets the Chicago area on April 15, 2020. (Antonio Perez / Chicago Tribune)
April 3: Chicago's first 70-degree day of 2020.
April 7: Chicago's first 80-degree day of 2020 ends with a dramatic hail event.
April 18: The previous day's snow storm — which dumped almost 4 inches of snow at O'Hare Airport — is eclipsed by warmth.
April 28-30: Heavy rain leads to flooding of area rivers.
May: Record rain and tornadoes
A woman wearing a face mask walks past an advertisement for the Chicago Women's Park and Gardens in the 1800 block of South Indiana Avenue on May 26, 2020, in Chicago. (John J. Kim/Chicago Tribune)
May 9: The temperature at O'Hare drops below freezing — the first time in 18 years that it's done so this late in the spring.
May 19: The month's precipitation record is broken for the third time in three consecutive years.
May 23: Severe storms produce a few brief tornadoes.
June: Remnants of a tropical storm pass by
A double rainbow appears over the skyline after a rainstorm on June 26, 2020, in Chicago. (John J. Kim / Chicago Tribune)
June 2: The day's record high temperature is broken when 94 degrees is recorded at O'Hare airport.
June 9: Remnants of Tropical Storm Cristobal pass over the area. It's at least the 16th time since 1886 that Chicago has experienced heavy rain and flooding, strong winds and an occasional tornado due to remnants from tropical storms that have traveled northwest from the Atlantic Basin.
June 26-27: Severe storms produce heavy rain and strong winds.
June 29: O'Hare airport records a heat index of 102°.
June 30: A weak microburst is detected on weather radar.
July: Hot start to summer and a pulse storm
The sun sets behind Wrigley Field during the sixth inning of an opening day baseball game between the Chicago Cubs and the Milwaukee Brewers, on July, 24, 2020, in Chicago. (David Banks/AP)
July 5: It's the 12th day of temperatures in the 90s or higher — more than twice the average year to date. The National Weather Service determines summer 2020 is off to the 7th hottest start on record.
July 26: A fast-developing storm with gusty winds and heavy rain, called a pulse storm, is captured on video.
End of the month: July 2020 is the fourth warmest on record in Chicago.
August: A derecho spawns tornadoes and summer temperature record
Neighbors with a hand saw clear a down tree blocking Kedzie Avenue in Logan Square on Monday, Aug. 10, 2020 after a large storm passed through the city. (Brian Cassella/Chicago Tribune) (Brian Cassella / Chicago Tribune)
Aug. 10: A widespread storm with hurricane-force, straight-line winds, known as a derecho, spawns 15 tornadoes in northeastern Illinois. It was the second-most tornadoes produced in a single, calendar day in the Chicago area. The unique weather phenomenon has impacted Chicago at least nine times since 1965.
End of the month: The sixth driest August on record ends the warmest summer on record in Chicago.
September: Smoke from Western wildfires makes for hazy skies
A jet ascends from O'Hare International Airport in front of the setting sun, dimmed by smoke from Western states' wildfires, on Sept. 21, 2020, in Chicago. (John J. Kim / Chicago Tribune)
Sept. 13: It's the eighth consecutive day of measurable precipitation.
Sept. 19: Smoke from wildfires in the West wafts into the Chicago area creating hazy skies and dramatic sunsets.
October: A teeny, tiny bit of snow
Alpacas left to right: Ventania, 19, Chach'ella, 13, and Lady Talbot, 14, peer our from the barn in the snowfall at J4 Alpacas farm on Oct. 26, 2020 in Bull Valley. They are Suri alpacas. The farm was founded in 1996 by the Morgan family. They are currently winding down their farm and have just 7 alpacas left, but at one time they had 85 alpacas living on the farm. (Stacey Wescott/Chicago Tribune)
Notable event
Oct. 26: First snow of the season, but it's not measurable.
November: Warm temperatures, extraordinary wind
Benjamin Scaffer-Dowling, 3, plays in autumn leaves on Nov. 7, 2020, while talking a walk with his mother, Jessica Schaffer, and aunt Ayalmesh Stonys in their neighborhood in Chicago. Schaffer said, "It's a beautiful weather, and the election results came through. So we decided to celebrate and have some fun." (Youngrae Kim / Chicago Tribune)
Nov. 4-10: Seven consecutive days of temperature highs in the 70s make the stretch the latest in the year that it's been that warm. The warm weather is pushed out by a powerful cold front, which brings severe storms and strong winds to Chicago. DeKalb and Kane counties experience EF-0 tornadoes.
Nov. 15: Chicago is experiencing an extraordinarily windy fall.
Nov. 24: O'Hare airport records its first measurable snowfall of the season — 0.7 inches.
December: Clouds block view of planets
Aidan Fitzpatrick walks with her dog Lucy near the lighthouse at Loyola Beach as high waves batter the lakeshore in Chicago on Dec. 12, 2020. (Youngrae Kim / Chicago Tribune)
Dec. 1: Meteorological winter begins.
Dec. 21: Cloudy skies prevent people in Chicago from viewing the alignment of Jupiter and Saturn on the winter solstice.
What to expect this winter
Borchardt says the outlook for the new year predicts a higher chance of above average precipitation than average or below — but cautioned that this does not necessarily mean more snow for our area. Temperature-wise, he says there are currently no signs that it will be either much colder or much warmer than an average winter.
"At any rate, Chicago winters will always include warm stretches and cold stretches, as well as periods of accumulating snow, no matter the year," Borchardt said.
(National Weather Service Chicago)
Sources: National Weather Service; Chicago Tribune reporting, archives and photos
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