An upper-level trough deepened over the central Plains, developing a deep area of surface low pressure that tracked from Iowa across Illinois. The system produced heavy snow across all of Wisconsin, with portions of the south initially seeing rain, limiting snow amounts there. Gusty winds of 40 to 60 mph accompanied the heavy snow, producing blizzard conditions over most of southern Wisconsin from the afternoon of December 11th into the afternoon of December 12th. Snowfall totals ranged from 6 inches to 12 inches along and north of a Mineral Point to Port Washington line. A state of emergency was declared for all 72 counties by Governor James Doyle. The driving conditions were dire enough for the state Department of Transportation and the State patrol to issue a travel advisory recommending no travel on any Wisconsin highways from the evening of the 11th through the day on the 12th. Interestate-43 was reduced to one lane in each direction at times, with Interstate-94 closed for 3 1/2 hours due to a multi-car accident. The blinding wind-driven snow caused many authorities to pull their snowplows from the roads until conditions improved. The near-whiteout conditions on Sunday caused many churches to cancel services. Many tree limbs and power lines were brought down by the combination of strong winds and heavy snow. WE Energies reported as many as 20,000 customers were without power during the time period  from Saturday night the 11th through Sunday evening the 12th, including 6,000 in Dodge,Washington and Ozaukee counties with more than 100 crews out in the field. Alliant Energy reported 5,800 customers without power in Fond Du Lac and Sheboygan counties early Sunday the 12th.

Blizzard in DANE, WISCONSIN
From 11-DEC-10 16:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds between 50 and 60 mph combined with heavy snow to produce visibilities of under 1/4 mile, as well as blowing and drifting snow. Snowfall totals ranged between 6 and 9 inches. A vehicle crash near the Dane/Columbia County border around 830 pm CST on the 11th closed all northbound lanes of Interstate 39-90-94. The city of Madison had 175 pieces of equipment out on Sunday the 12th to try and clear snow from city streets. The ASOS at Dane County Regional Airport recorded a peak wind gust of 56 mph.

Blizzard in COLUMBIA, WISCONSIN
From 11-DEC-10 12:00:00 to 12-DEC-10 11:20:00 (CST-6)
Reported by: COOP Observer

Heavy snowfall between 10 and 13 inches was accompanied by wind gusts up to 50 mph, producing low visibilities of 1/4 mile or less as well as blowing and drifting snow. Law enforcement officials reported many cars stuck in the drifts, with county and town roads blown over with snow.

Blizzard in SHEBOYGAN, WISCONSIN
From 11-DEC-10 16:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to near 60 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. Snowfall totals ranged between 7 and 10 inches. Random Lake, Plymouth and Elkhart Lake all measured 10 inches of snow. A peak wind of 58 mph was recorded at the C-MAN station along the lake shore in Sheboygan, with the ASOS at the Sheboygan airport recording a 47 mph wind gust. Alliant Energy reported 1,300 customers without power in the county, with WE Energies reporting scattered outages across southern sections of the county. Law enforcement reported 50 reports of cars in ditches and minor accidents, with one minor injury.

Blizzard in WASHINGTON, WISCONSIN
From 11-DEC-10 16:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to 40 mph combined with heavy snow to produce near whiteout conditions with visibilities less than 1/4 mile, as well as blowing and drifting snow with drifts up to 3 feet. Snowfall totals ranged between 6 and 11 inches.

Blizzard in FOND DU LAC, WISCONSIN
From 11-DEC-10 16:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to 50 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. Snowfall totals ranged between 9 and 11 inches. The ASOS at Fond Du Lac airport recorded a peak wind gust of 51 mph.

Blizzard in ROCK, WISCONSIN
From 11-DEC-10 21:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to 50 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. Snowfall totals only ranged between 2 and 5 inches, but the blowing and drifting snow caused State Highway 14, between State Highway 140 in Rock County to State Highway 89 in Walworth County, to be closed during the afternoon of December 12th. A 21-year-old woman was killed around 1:45 pm CST Sunday the 12th when the SUV she was riding in lost control on the ice-covered southbound lanes of Interstate 39-90 about 1/2 mile south of Manogue Road and slid off the road into the median, hitting two trees. The driver of the car and another passenger received non-life-threatening injuries.

Blizzard in SAUK, WISCONSIN
From 11-DEC-10 12:00:00 to 12-DEC-10 11:20:00 (CST-6)
Reported by: COOP Observer

Heavy snowfall between 10 and 13 inches was accompanied by wind gusts up to 40 mph, producing low visibilities of 1/4 mile or less as well as blowing and drifting snow. The ASOS at the Lone Rock airport recorded a 41 mph wind gust.

Blizzard in WAUKESHA, WISCONSIN
From 11-DEC-10 21:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to near 50 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. Snowfall totals ranged between 3 and 5 inches. The AWOS at Crites Field in Waukesha recorded a peak wind gust of 47 mph.

Blizzard in DODGE, WISCONSIN
From 11-DEC-10 16:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to 40 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. Snowfall totals ranged between 7 and 11 inches, with 10 inches measured in the Hartford area. Sheriff deputies reportedrpeorted more than 130 runoffs and quite a few minor accidents. The AWOS at Juneau airport recorded a peak wind gust of 39 mph.

Blizzard in JEFFERSON, WISCONSIN
From 11-DEC-10 21:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to 40 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. Snowfall totals ranged between 5 and 9 inches. A seven-car accident, with 4 injuries, on Interstate-94 near Johnson Creek Sunday December 12th closed about 8 miles of the interstate for three and one-half hours. Law enforcement officials reported 75 traffic accidents between 11 pm Saturday the 11th and 7 am Sunday the 12th.

Blizzard in GREEN LAKE, WISCONSIN
From 11-DEC-10 12:00:00 to 12-DEC-10 11:20:00 (CST-6)
Reported by: COOP Observer

Heavy snowfall between 10 and 13 inches was accompanied by wind gusts up to 40 mph, producing low visibilities of 1/4 mile or less as well as blowing and drifting snow.

Blizzard in GREEN, WISCONSIN
From 11-DEC-10 16:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to near 50 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. Snowfall totals ranged between 4 and 6 inches. Law enforcement officials reported one rollover accident and many runoffs due to snow covered and drifted roads. Monroe received 5 inches of snow, with the AWOS at the airport recording a 48 mph wind gust at 415 am on the 12th.

Blizzard in LAFAYETTE, WISCONSIN
From 11-DEC-10 16:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to 40 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. Snowfall totals ranged between 3 and 6 inches.

Blizzard in OZAUKEE, WISCONSIN
From 11-DEC-10 16:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to 40 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. Snowfall totals ranged between 2 and 8 inches.

Blizzard in MARQUETTE, WISCONSIN
From 11-DEC-10 12:00:00 to 12-DEC-10 11:20:00 (CST-6)
Reported by: COOP Observer

Heavy snowfall between 11 and 13 inches was accompanied by wind gusts up to 40 mph, producing low visibilities of 1/4 mile or less as well as blowing and drifting snow.

Blizzard in IOWA, WISCONSIN
From 11-DEC-10 16:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to 40 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. Snowfall totals ranged between 4 and 6 inches. County officials reported some local roads closed due to drifts.

Blizzard in WALWORTH, WISCONSIN
From 11-DEC-10 21:00:00 to 12-DEC-10 15:07:00 (CST-6)
Reported by: COOP Observer

Gusty winds to 50 mph combined with heavy snow to produce visibilities of 1/4 mile or less, as well as blowing and drifting snow. U.S. Highway 14 was closed from State Highway 89 west to State Highway 140 in Rock County due to the blowing and drifting snow. Snowfall totals ranged between 3 and 5 inches.