Chicago Area Weather Disasters

Jim Allsopp, National Weather Service, Chicago/Romeoville

First Lego League Kickoff September 8, 2013

Oak Lawn Tornado 1967

Chicago Blizzard 2011

Chicago Big Snow 1967

Rockford Flash Flood 2006

Illinois River Flood 2008

Plainfield Tornado 1990

What Kind of Weather Disasters does Chicago Experience?• Tornadoes• River Floods/Flash Floods• Lightning• Hail• Thunderstorm Winds• Winter Storms • Extreme Heat• Extreme Cold• Drought• Lake Michigan – coastal flood, rip currents,

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Storm-Related Fatalities Only

All Weather-Related Fatalities

Chicago AreaTornadoes• Tornadoes occur

anywhere in the Chicago metro area

• Tornadoes can strike large cities – Ft. Worth, Miami, Nashville, Salt Lake City

• Tornadoes occur at the lakefront

EF Tornado Damage Scale

Weak Tornado (70-75%)• EF0 – winds 65 to 85 mph• EF1 – winds 86 to 110 mph Strong Tornado (20-25%)• EF2 – winds 111 to 135 mph• EF3 – winds 136 to 165 mph

Violent Tornado (<2%)• EF4 – winds 166 to 200 mph• EF5 – winds over 200 mph

EF4 & EF5 cause 85% of tornado fatalities!

Chicago Area’s Violent (F4-F5) Tornadoes

• 10 Violent Tornadoes in 90 Years• March 28, 1920 – F4, Melrose Park and Maywood• April 7, 1948 – F4 Manteno, IL to Hebron, IN• April 17, 1963 – F4 Essex & Bourbonnais, IL to

Medaryville, IN• April 11, 1965 (Palm Sunday) – F4 Crystal Lake• April 21, 1967 – 3 F4s Belvidere, Lake Zurich, Oak

Lawn• March 20, 1976 – F4 Deep River to MI City, IN• June 13, 1976 – F4 Lemont• August 28, 1990 – F5 Plainfield

April 21, 1967 - Deadliest

• 10 tornadoes in the Chicago area

• 3 F4 Tornadoes, 58 killed, 1000 injured

• Part of a large outbreak across the Midwest

Belvidere• F4• 25 mile path, ½ mile

wide.• 24 fatalities, 500

injured

• 13 fatalities and 300 injuries occurred as a dozen busses were tossed at Belvidere High School at school dismissal.

Oak Lawn• F4• 16 mile path, 200

yards wide. • 33 killed, 500

injured

• Struck busy intersection at 500 PM on a Friday afternoon.

June 20, 1976 – Widest Path• Lemont – Argonne Lab• F4• 3.3 mile path, 1 mile wide!• 2 killed, 23 injured.

August 28, 1990 - Strongest• Oswego – Plainfield – Joliet• F5• 16 mile path, 1/4 mile wide• 29 killed, 350 injured

• Only F5 ever in Chicago area• Only F5 in U.S. in August

Plainfield

Chicago’s Worst Heat Waves

• Late July Heat Wave in 1916• July 26 -July 30 most oppressive period of heat ever in Chicago. • Min temp in the 80s for 5 straight nights!

• 1930s Dust Bowl Summers• A series of hot dry summers in the 1930s. • June of 1933 - hottest June on record. • Chicago's official all time high of 105 set July 24 1934. (109 at Midway on July 23)• July 6 through 14, 1936 - eight 100s in a row at Midway. • July 14, 1936 - hottest day ever over northern IL. • 112 at Rockford, 111 at Aurora , 104 at Midway.

Chicago’s Worst Heat Waves• Hot Summers of the 1950s

• 6 of 13 hottest summers1949-1959. • July 1955 - hottest month on record. • 1955 - Chicago’s all time hottest summer.• 46 days in the 90s including 11 straight (also in 1953 and 1954)

• The Hot Dry Summer of 1988• 47 days with temperatures in the 90s, 7 days in the 100s. Both

records.

• The Deadly Summer of 1995• 629 people died in July heat wave. Deadliest weather event in

Chicago history. • July 13 - 104 at O’Hare, 106 at Midway, Heat index 119 at O’Hare,

125 at Midway. • 2nd hottest summer on record.

Chicago Worst Winter StormsJan 26-27 1967 Jan 12-14 1979 Jan 1-3 1999 Jan 31-Feb 2 2011

Snowfall (inches) 23.0 20.3 21.6 21.2

Liquid Equivalent (inches)

2.40 1.36 1.39 1.57

snow/liquid ratio 9.6 to 1 14.9 to 1 15.5 to 1 13.5 to 1

duration of accumulating snow (hours)

~29 ~38 ~54 ~40

peak wind gust (mph)

53 39 43 61

maximum snow depth (inches)

23 29 18 18

snow stayed on the ground through(number of days)

March 942 days

March 651 days

January 2321 days

February 1716 days

temperatures after the storm

Jan 28-29low 15/high 28low 20/high 30

Jan 15-16low -19/high 9low -2/high 22

Jan 4-5low -9/high 5low -16/high 18

Feb 3-4low -6/high 16low 5/high 25

Chicago’s Worst Cold Snaps• The Winter of 1903-1904• The coldest winter on record.

• January, 1912• Second coldest January on record. • Record stretch of 10 days in a row with lows below zero. • 13 days below zero for the month.

• Bitter Cold Christmas 1983 • Dec 22-25 temperature below zero for 100 consecutive

hours.• Dec 24th low temp of -25, high of -11, coldest day in

Chicago.

• Record Cold January 20, 1985• -27F. All time coldest temperature for Chicago.

Chicago’s Worst Floods• October 9-11, 1954• Torrential rain over northern Illinois resulted in

record flooding. • Chicago rainfall for the 3 day period 6.72 inches.

• August 14-15, 1987 • Record Salt Creek flood. 16,000 buildings affected. • Record rainfall 9.35 inches fell 9 PM August 13th - 3

PM August 14th. • O’Hare completely surrounded by water. Kennedy

and Edens Expressways had 300 vehicles stranded in water up to 6 feet deep.

Chicago’s Worst Floods• July 18-20 1996

• Record rainfall over southwest suburbs. • State 24 rainfall record of 16.94 inches at Aurora. • Record flood at 19 river gages - DuPage, Fox, Illinois.

• September 2008• Remnants of tropical storms Gustav and Ike brought

torrential rainfall • Total Sep rainfall for Chicago was 13.63 inches. • Flooding caused the Brookfield Zoo to closed for the first

time.

• April 17-18, 2013• 4 to 8 inches of rain on already saturated soil• Record river flooding on Des Plaines River, North Branch

of Chicago River, and Illinois River• Illinois River dam damaged by barges. Marseilles flooded.

The Great Chicago Fire October 8-10, 1871• Very dry conditions leading up to the fire• Cold front with strong dry southwest winds October

8, 1871• Almost everything made of wood – buildings,

sidewalks, roads, piles of firewood for heating. Flammable shingles and tar roofs.

• 300 killed, 100,000 homeless (1/3 of the population)

Several Other Fires Around the Great Lakes• Peshtigo, Wisconsin

Fire• Peshtigo Firestorm – wall

of flame 1 mile high, 5 miles wide and moving 90 mph• 1500-2500 killed

(greatest death toll for any US fire)• 1.2 million acres

consumed• Fire generated a tornado

that “threw rail cars and houses into the air”.

Web Resources• http://weather.gov/chicago• From menu on left “top news archives”

8/28/2013 First Lego League• Office tours Mon-Fri 800 AM – 430 PM• Open House Sep 21 900 AM to 300 PM

J im.allsopp@noaa.gov

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