Many will remember 2011 as a year of extreme weather events. From snowstorms to extreme drought, hurricanes to raging wildfires, epic floods to heat waves, 2011 shattered records with a total of twelve weather and climate disasters each causing at least $1 billion in damages. As 2011 is drawing to a close, it is time to look back at some top weather events that occurred here in the Chicagoland region. I have compiled a list of top 10 weather events that impacted the Chicagoland area this year.
10) February 9-10 Extreme Cold
- On February 9th and 10th, a strong, arctic cold front brought in behind it, the coldest 48 hours of winter to the region. On the 9th, Chicago-O’Hare recorded a nighttime low temperature of -2 degrees and a daytime high of only 12 degrees. On the 10th the low was -9 degrees and the high was 16 degrees. At Rockford on the 9th, the low was -7 degrees and the high was only 9 degrees. On the 10th, the low temperature was -20 degrees (a record for the date) and the high temperature was 17 degrees. Other low temperatures on the 10th included -20 degrees at West Chicago, -21 degrees at Aurora, Rochelle and Marengo.
9) Lake Michigan Wind Storm October 19-20
- An area of low pressure over Kentucky moved northward towards the Great Lakes region intensifying into a powerful autumn storm. Winds equivalent of that of a tropical storm occurred over Lake Michigan and the Illinois and Indiana shores from Michigan City to Waukegan October 19-20. Wind gust topped 60 mph along the lake creating waves up to 20 feet high. As many as 20 boats were damaged or destroyed when they broke free from their moorings in Monroe harbor.
8) June 4 Northwest Indiana High Winds
- On June 4th, severe thunderstorms produced a swath of wind damage from roughly St. John and Crown Point in Lake County Indiana, southeastward into southwest Porter and northern Jasper Counties. Winds were estimated to 90 to 110 mph in some locations. Trees and signs were blown down and semis were overturned. A weigh station on I-65 was damaged. The most intense damage occurred near Route 2 between I-65 and Route 231 southwest of Hebron. Large groves of trees were flattened, garages, outbuildings and grain bins were destroyed and metal truss power line towers were collapsed.
7) Late May Tornadoes
- On May 22, a strong line of thunderstorms moved through north central Illinois producing damaging winds and several tornadoes. An EF1 tornado produced a 29 mile long path through Ogle and Winnebago Counties. The tornado started just east of Forreston. Two mobile homes were severely damaged in Ogle County. In Winnebago County several outbuildings were damaged or destroyed and the roof was damaged at Kennedy Middle School on the west side of Rockford. Many large trees and limbs were snapped by the tornado as well. At least four other small brief tornadoes were documented in Ogle and Winnebago Counties. In addition there was widespread tree damage from strong straight-line winds over Winnebago County. Another brief EF1 tornado occurred on the north side of Rensselaer in Jasper County, Indiana, damaging a Farm Bureau building and an Agricultural Extension office. A series of small supercells developed in the morning of May 25 producing several tornadoes over east central Illinois and northwest Indiana. An EF1 tornado occurred northeast of Hopkins Park in Kankakee County. The tornado damaged a garage, a grain bin, and other outbuildings, poles and trees. Two tornadoes occurred in Newton County, one rated EF1 and the other EF2. The twisters mostly damaged outbuildings, grain bins, trees and poles. Two more tornadoes occurred in Jasper County, including one that hit the southeast side of Rensselaer – the second tornado in three days to hit the town. Storms also produced wind damage in Iroquois County and elsewhere in northwest Indiana
6) June 30 Lakefront Supercell
- On the evening of June 30th, a powerful supercell thunderstorm developed just off the Illinois lakefront. The storm spawned a waterspout over Lake Michigan. The rear flank of the storm produced winds to 80 mph along the shoreline of Lake County blowing down hundreds of trees. Later the storm produced hail up to the size of baseballs over the west side of Chicago. Hail caused $2 million in damage to glass panels at the Garfield Park Conservatory. Also on the west side of Chicago, 130 police cars were damaged by large hail.
5) June 21 Chicago area wind and tornadoes
- On the evening of June 21st, a powerful line of thunderstorms moved southwest to northeast from LaSalle County to the Chicago metro area producing damaging winds and a couple of brief tornadoes. Widespread winds of 50 to 70 mph blew down hundreds of trees, tree limbs and power lines. There were scattered pockets of winds 70 to 90 mph with more extensive tree damage and some structural damage over the west and north suburbs of Chicago. The worst of the storms hit DuPage County, north and west Cook County and eastern Lake County. Some trees and limbs fell on homes and vehicles. Two people were injured when a tree crushed a car on the north side of Chicago. The roof of a building near Wrigley Field was damaged. Apartment roofs were damaged in Maine Township and Prospect Heights. A wind gust to 81 mph was measured at Palwaukee Airport, where hangars were damaged and two planes were flipped. Brief tornadoes occurred in Downers Grove and Mt. Prospect, where more extensive tree damage occurred.
4) July 11 Derecho
- A long lived, intense line of thunderstorms, known as a Derecho, swept across northern Illinois in the early morning hours of July 11. The winds flattened corn fields, blew down power lines and poles, and damaged thousands of trees. The worst damage occurred over the northern tier of Illinois counties from Winnebago and Ogle Counties eastward to the north suburbs of Chicago. The high winds and falling trees caused roof damage to buildings and homes. Falling trees and limbs also damaged vehicles. A few semis were overturned. A man was killed on the west side of Chicago when a tree fell on his car. As many as 850,000 customers lost power. ComEd deployed more resources to this storm than any event in its history. A total of 1100 crews from 14 states repaired or replaced 78 miles of wire, 600 poles and 1000 transformers.
3) July 22-23 Flood
- Strong and nearly stationary thunderstorms with cloud tops as high as 60,000ft, produced locally heavy rain and flooding over parts of the north suburbs of Chicago on July 22. Additional thunderstorms developed later that night into the morning hours of July 23 and produced torrential rain over parts of Cook and DuPage Counties. Rainfall rates on the order of 2 to 4 inches per hour resulted in widespread flash flooding. The results were devastating. Thousands of basements were flooded, some with as much as 8 to 10 feet of water and sewage. Many roads, viaducts and intersections were flooded and many cars were stranded in flood waters. Sections of several major highways including Interstate 57, Interstate 94 and Lake Shore Drive were closed by the flood waters. The heaviest rain fell over northern Cook County. A new daily rainfall record for July 23 was recorded at O’Hare with 6.86 inches of rain. The total rainfall for the event at O’Hare was 8.20 inches, which accounted for 74% of the rain that fell for the entire month of July. The total for the month of July was 11.15 inches, which was a record and 7.64 inches above normal. Other rainfall totals included 7.25 inches in Arlington Heights, 7.17 inches in Elk Grove Village, and 6.06 inches at Palwaukee Airport. Rainfall was 3 to 6 inches across parts of DuPage and central and southern Cook Counties. Lightning was blamed for at least four house fires including one in Naperville that caused over $300,000 in damage. The round of storms also produced one tornado in Indiana.
2) July 17-21 Heat Wave
- A stretch of intense and deadly heat gripped a vast majority of the country affecting as many as 141 million Americans. Northern Illinois and northwest Indiana were a part of this deadly heat wave through mid and late July. Temperatures were in the 90s for 5 straight days, topping out at 99F on the 20th and 21st at Chicago’s O’Hare Airport, while Rockford had highs of 100F on the 19th and 20th. These were the first 100F degree temperatures in Rockford since 1989. Sixteen people died from the heat in Cook County. Thunderstorms brought some relief on the 22nd and 23rd but very warm weather persisted through the end of the month. In Chicago, July ended up 5.7 degrees above normal, making it the third warmest July on record. At Rockford, July was 6.0 degrees above normal. It was the fifth warmest July on record.
1) February 1-2 Blizzard
Of all of the significant weather events that occurred in the Chicago area, none comes close to the blizzard that crippled the entire city early February. The February 1-2 Blizzard also know as the Groundhog Day Blizzard, was one of the most powerful winter storms in Chicago history. Although coming in at third place (after the 1967 and 199 storms) in terms of snow intensity, wind, and lightning production, this blizzard was second to none.
The onset of the snow began late in the day on January 31 as a weak shortwave ahead of the main storm. The weak shortwave dumped a couple of inches across the area. The main storm moved out of the southern Plains into the area on the afternoon of February 1 as conditions rapidly deteriorated. Blizzard conditions developed and persisted from the evening of February 1 to the morning of February 2 before tapering off.
The rate of snowfall during this period was so intense at a point that snow removers couldn’t keep up. This combined with continuos blowing and driftin snow resulted in thousands of motorist being stuck on several major highways including I-57, I-94, and Lake Shore Drive. Some were trapped in their vehicles for up to 12 hours. The National Guard was activated to assist stranded motorists. More than 1300 flights were cancelled at O’Hare and Midway Airports, and Amtrak service out of Chicago was halted.
The storm was also known for its lightning production and wind. There was frequent lightning and thunder in Chicago and the southwest suburbs during the height of the storm on the evening of February 1, and small hail was reported in a thunderstorm at Midway Airport. Winds gusted as high as 61 mph at O’Hare and visibility was reduced to at least one quarter mile for eleven consecutive hours.
By the time the storm was over, as many as 21.2 inches of snow had fallen at O’Hare Airport. 15.1 inches had fallen at Rockford Airport, making this the third largest snowstorm on record for both cities. Other snow totals included 17.1 inches at National Weather Service in Romeoville, 21.7 inches at Chicago Midway Airport, 24.2 inches at Beach Park, 23.7 inches at Elk Grove Village, 23.5 inches at Spring Grove and 23.1 inches at Inverness.
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