2011 Lake Michigan hurricane season summary updated
The 2011 Lake Michigan hurricane season began on June 1, 2011, and ended on November 30, 2011. However, any cyclone that formed between January 1, 2011 and December 31, 2011 would've factored into the season's total. This year is the first year in modern records to have tropical and subtropical cyclones form in Lake Michigan.

Season summary

The 2011 season was characterized by many weak, short-lived storms. Aside from Hurricanes Barry and Erin, none of the systems went past tropical storm status or lasted more than 24 hours. In addition, none of the storms (except Barry) had significant land impact.

Four systems (Andrea, Barry, Dean, and Erin) affected land in some way whatsoever. Andrea and Dean hit Chicago directly, but the damage from these systems only totaled $400,000. Erin brushed the central western coast of Michigan, then hit the Door Peninsula as a moderate extratropical system, causing $100,000 and killing three along its path. Barry had the worst impact. It caused $40.5 billion of damage in Wisconsin, and killed 77 (75 of those happened at landfall).

Season Timeline

Saffir-Simpson Hurricane Scale

List of Storms

Tropical Depression One

Tropical depression (SSHWS)
235px-Melissa 29 sept 2007 1245Z 
DurationJuly 14 – July 14
Peak intensity35 mph (55 km/h) (1-min)  1004 mbar (hPa)

On July 14, a thunderstorm with an area of closed circulation developed, and was classified as the first tropical depression in Lake Michigan history. However, it would not live long. As Lake Michigan is not a large place for cyclones to form, just 6 hours after the depression first was designated, the depreession was eaten up by a non-tropical thunderstorm.

No land areas were affected by Tropical Depression One.

Subtropical Storm Andrea

Subtropical storm (SSHWS)
265182main 235A1066 655 
DurationJuly 27 – July 28
Peak intensity50 mph (85 km/h) (1-min)  999 mbar (hPa)

The storm that later became Subtropical Storm Andrea began as part of a thunderstorm complex. As the complex moved over Lake Michigan, a closed circulation started to form, and it looked like a tropical cyclone on satellite images. Based on the data, and the fact that Dvorak numbers were at 2.0, the area became Tropical Depression Two about 400 miles northeast of Chicago. But something weird was going on. The newly-formed system began to show hybrid features. Six hours later, the storm was redesignated as Subtropical Depression One. It rapidly became a subtropical storm, with the weather centers naming it Andrea. Andrea became the first named cyclone in Lake Michigan history. Shortly after being named, it continued to grow. Soon, it was the size of Rhode Island. Even though Andrea was abnormally large, it only made it to 45 mph before land interaction wiith northeastern Illinois weakened it to 40 mph. It then hit the Chicago Loop at that intensity. Radar from Chicago weather stations tracked the center of Andrea, until it lost its identity near O'Hare Airport.

Even though Andrea was a rare storm, its effects were minimal. No deaths (direct or indirect) were reported. However, 15 weather stations recorded mesurable rain, the most being 2.04 inches at Chicago Midway Airport. And $250,000 of damage occured when lightning struck the roof of a home in the northwestern part of the city. Elsewhere, impacts were limited to percipitation.

Hurricane Barry

Category 5 hurricane (SSHWS)
DurationAugust 1 – August 6
Peak intensity185 mph (295 km/h) (1-min)  924 mbar (hPa)

On August 1, a unusual invest about 100 miles off the coast of Waukegan, Illinois became Tropical Depression Three. Despite the proximity to land, the depression was very small, and tons of incredibly warm waters were ahead of the system. Although almost all of the forecasts predicted Tropical Depression Three to become a tropical storm, there was also about 20-25 knots of wind shear, which suppresses development. As a result, the depression could not get past 35 mph and 1007 mb because it was facing shear. At the start of the next day, it was still a measley tropical depression. However, the shear decreased, and this was bad news! Tropical Depression Three began to rapidly intensify, and in six hours, it was a 40 mph tropical storm, and it was named Barry. Barry reached 50 mph winds, then its size began to increase. Soon, it was covering all of southern Lake Michigan. For people in Wisconsin, this was among the largest storms ever observed there. As waters got warmer, Barry began to explosively intensify. It turned from a moderate tropical storm to a 80 mph Category 1 hurricane in barely six hours, becoming the first hurricane of the year. For the first time in Lake Michigan hurricane history, a Hurricane Hunters flight was sent to investigate the storm. When the aircraft reached the center, winds of 121 mph were recored. Based on this data, Barry was upgraded to a Category 3 hurricane, becoming the first major hurricane (Cat. 3-4-5 on the SSHS) of the year. Less than 30 minutes after the upgrade, a wind speed of 151 mph was recorded in Two Rivers, prompting the upgrade into a Category 4 hurricane. Things were going bad because it looked like Barry was going to hit Wisconsin as a 55 mph storm, now a 155 mph Category 4 hurricane was barreling down on them. Just 3 hours before landfall, the same weather station that recorded the 151 mph wind speed then recorded a 184 mph windspeed. Barry became a monster Category 5 hurricane with a 904 mb pressure. Its 185 mph windspeed was an all-time record for the Great Lakes, and it was the first storm worldwide since Typhoon Megi to have a 185+ mph windspeed. To make things worse, Barry did not weaken, and hit about 20 miles south of Two Rivers, Wisconsin at that intensity, becoming the strongest storm to make landfall in Lake Michigan history. Interaction with land weakened it to 135 mph, and the size of Barry started to shrink. By the time it was about 50 miles inland, Barry had become a 75 mph Category 1 hurricane. It became a tropical storm, and its foreward speed was increasing. Twelve hours later, the former hurricane entered Lake Winnebago as a weak tropical storm. There, it began a sharp turn to the northeast. Barry continued a weakening trend, and was downgraded into a tropical depression over northeastern Lake Winnebago. The depression accelerated in speed, and quickly reached Green Bay. Radar screens confirmed it passed over the city. Barry reached Green Bay, and brushed the southeast coastline before becoming extratropical over the Door Peninsula. The extratropical remnant continued to pass over the Door Peninsula, and emerged into Lake Michigan. It gained gale-force winds, and acclereated to the east. The remnants then hit northwestern Michigan with the force of a tropical storm. They continued east, then gradually turned east-southeast. The identity of Barry was identifable as far east as Toronto, where they were absorbed into a frontal boundary.

The impact from Barry was widespread and devestating. 77 people died in the brunt of the storm, and $40.5 billion damage was caused. The worst impact occured in Two Rivers. A tornado rated EF3 struck the city, severely damaging the town. Villages and cities were wiped off the map by Barry's onslaught. 74 people died in Two Rivers as a result. Elsewhere, 2 people died from heavy surf in Milwaukee and 1 died from a lightning strike in Green Bay. In conclusion, Barry will be remembered as the worst storm in Wisconsin history.

In post-season review, Barry's pressure was lowered down from 924 mb to 904 mb.

Tropical Storm Chantal

Tropical storm (SSHWS)
TD2 aug 12 2009 1335Z 
DurationAugust 19 – August 20
Peak intensity45 mph (75 km/h) (1-min)  1012 mbar (hPa)

A tropical depression formed from an area of convection on August 19. It was a very small cyclone on satellite imagery. It would not strengthen a lot, but 12 hours later, Dvorak numbers of T3.0 were assigned. As a result, the depression was upgraded to Tropical Storm Chantal. Chantal wouldn't maintain its intensity for long. The system encountered wind shear because it was in an unfavorable area, and degenerated into a vortex only six hours after being named.

No land areas were affected by Tropical Storm Chantal.

Tropical Storm Dean

Tropical storm (SSHWS)
DurationSeptember 15 – September 15
Peak intensity70 mph (110 km/h) (1-min)  995 mbar (hPa)

Nearly a month after Chantal dissipated, a weak, low pressure area was detected off the coast of Wilmette, Illinois. Forecasters deemed the storm extratropical, however, Dvorak numbers of T3.5 were being assigned. Due to the uncertainties, a Hurricane Hunters flight was sent to investigate the area. The results were that a closed circulation was found, and 60 mph winds were recorded. Based on this, the area became Tropical Storm Dean. Dean did not intensify further, and started to make landfall. Dean made landfall around the same spot Subtropical Storm Andrea did, on the afternoon of September 15. Like Andrea, Dean rapidly weakened, and became post-tropical just four hours after making landfall.

Impact from Dean was very minimal. No deaths were reported, however, a weak F0 tornado caused damage along Micigan Avenue, devestating some shops. According to the White House, damage from Dean totaled $150,000.

Tropical Depression Six

Tropical depression (SSHWS)
220px-Tropical Storm Gert Aug 15 2011 1505Z 
DurationSeptember 28 – September 28
Peak intensity35 mph (55 km/h) (1-min)  1016 mbar (hPa)

Tropical Depression Six was a extremely unusual cyclone. It formed on September 28 when a closed circulation was discovered in a small area of clouds. It was upgraded to a depression. However, just two hours after being operationally classified, the depression was sudddenly torn apart by high wind shear. It was the shortest-lived tropical cyclone in Lake Michigan history. Because the system lasted barely two hours, some forecasters belive Tropical Depression Six may have never been a tropical cyclone.

No land areas were affected by Tropical Depression Six.

Hurricane Erin

Category 3 hurricane (SSHWS)
Hurricane Isaac (2000) GOES 9-28-00 
DurationNovember 11 – November 14
Peak intensity125 mph (205 km/h) (1-min)  946 mbar (hPa)

Hurricane Erin was the first tropical cyclone to be upgraded via Dvorak numbers for every upgrade or downgrade. On November 11, Dvorak numbers of T1.5 were assigned to a well-organized tropical wave about 50 miles of the western coast of Michigan's Lower Peninsula. Because these numbers were assigned, and its proximity to land, the wave was upgraded to a 30 mph tropical depression on the SSHS, with it being assigned the number Seven. Tropical Depression Seven slowly moved north-northeast toward the Michigan coast. As it did, numbers of T3.0 using the Dvorak techique were recorded, therefore, the depression became a 50 mph tropical storm. It was named Erin. After being named, Erin maintained its 50 mph intensity, until warmer waters off the coast caused it to rapidly intensify. Dvorak numbers of T4.0 led Erin to be upgraded to a weak 75 mph Category 1 hurricane, becoming the second and final hurricane of the year. Erin made a direct hit on the coast before moving offshore and reaching 90 mph. Its size increased, and warm waters led to a short, brief round of explosive intensification. The system reached 125 mph, becoming a major hurricane (the second major of the season). It would maintain Category 3 status for 24 hours before weakening to a Category 2 over unfavorable 77 degrees Farenheit sea surface temps. Six hours later, the rapidly weakening Erin fell down to 85 mph. Operationally, Erin was deemed extratropical at this time, however, later data revealed it had maintained hurricane status to its Wisconsin landfall. It made landfall in the southeastern Door Peninsula as a 75 mph hurricane, becoming one of only a few hurricanes to achieve this feat. The system became a tropical storm mshortly after landfall, then became extratropical. The extratropical remnant of Erin continued until they dissipated over Green Bay.

Despite the proximity to Michigan, Hurricane Erin caused no severe damage. However, three (3) surfers lost their lives when heavy surf from Erin came ashore. In Wisconsin, Erin caused no water damage, but strong winds affected areas that were already hit hard by Barry. Refugee shelters were destroyed by the winds. Green Bay families donated supplies to those affected by Barry and Erin in the aftermath.

Season effects

Storm name Dates active Category Wind Pressure Areas affected Damage (USD) Deaths (indirect deaths)
One July 14-July 14 Tropical Depression 30 mph 1004 mb None $0 0
Andrea July 27-July 28 Subtropical Storm 45 mph 999 mb Chicago (Chicago Loop) $250,000 0
Barry August 1-August 6 Category 5 Hurricane 185 mph 924 mb Two Rivers, Door Peninsula (Green Bay) $40.5 billion 75 (2)
Chantal August 19-August 20 Tropical Storm 40 mph 1012 mb None $0 0
Dean September 15-September 15 Tropical Storm 70 mph 995 mb Chicago (Chicago Loop) $150,000 0
Six September 28-September 28 Tropical Depression 35 mph 1016 mb None $0 0
Erin November 11-November 14 Category 3 Hurricane 125 mph 946 mb Western Michigan, Door Peninsula (Green Bay) $100,000 0 (3)
7 storms July 14-November 14 185 mph 924mb $41 billion 75 (5)