1. Chicago Area Weather Disasters
Oak Lawn Tornado 1967
Chicago Big Snow 1967
Rockford Flash Flood 2006
Chicago Blizzard 2011
Illinois River Flood 2008
Plainfield Tornado 1990
Jim Allsopp, National Weather Service, Chicago/Romeoville
First Lego League Kickoff September 8, 2013

2. 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, seiche

3. Storm-Related Fatalities Only

4. All Weather-Related Fatalities

5. Chicago Area Tornadoes
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

6. 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!

7. 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

8. 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

9. 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.

10. Oak Lawn F4 16 mile path, 200 yards wide. 33 killed, 500 injured
Struck busy intersection at 500 PM on a Friday afternoon.

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

12. 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

13. 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 hottest June on record.
Chicago's official all time high of 105 set July (109 at Midway on July 23)
July 6 through 14, eight 100s in a row at Midway.
July 14, hottest day ever over northern IL.
112 at Rockford, 111 at Aurora , 104 at Midway.

14. Chicago’s Worst Heat Waves
Hot Summers of the 1950s
6 of 13 hottest summers
July hottest month on record.
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 at O’Hare, 106 at Midway, Heat index 119 at O’Hare, 125 at Midway.
2nd hottest summer on record.

15. Chicago Worst Winter Storms
Jan
Jan
Jan
Jan 31-Feb
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
snow stayed on the ground through
(number of days)
March 9
42 days
March 6
51 days
January 23
21 days
February 17
16 days
temperatures after the storm
Jan 28-29
low 15/high 28
low 20/high 30
Jan 15-16
low -19/high 9
low -2/high 22
Jan 4-5
low -9/high 5
low -16/high 18
Feb 3-4
low -6/high 16
low 5/high 25

16. Chicago’s Worst Cold Snaps
The Winter of
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 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.

17. 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.

18. Chicago’s Worst Floods
July
Record rainfall over southwest suburbs.
State 24 rainfall record of 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 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.

19. 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)

20. 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
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”.

21. Web Resources http://weather.gov/chicago
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