Blizzard conditions developed over eastern Nebraska and adjacent portions of South Dakota and Iowa on Dec. 11 as an upper level low pressure developed rapidly over eastern Nebraska during the very early morning hours of that day.  The upper low then dropped into south central Iowa causing surface low pressure to spin-up over northeast Nebraska and then track southeast across Iowa.  Arctic air spilling in behind the system combined with the developing storm to produce the blizzard conditions as northwest winds of 30 to 40 mph with gusts over 50 mph were common over the area along with snowfall of 2 to 5 inches.  Higher snow amounts were observed from southeast South Dakota into Minnesota and northern Iowa.  However, the 2 to 5 inches of snow across much of eastern Nebraska and western Iowa, and the strong winds present, were enough to produce white-out conditions and to close some highways in northeast Nebraska.  Heavier snow totals included 5 inches in Neligh and Bloomfield Nebraska and near Little Sioux Iowa, 4 inches at the NWS in Valley and 3 inches in Fremont Nebraska and Harlan Iowa.  Temperatures which fell from the single digits to around zero or a little below late on the 11th and into the 12th combined with the strong winds to lower wind chill values to 20 below or a little colder, mainly in northeast Nebraska.

Blizzard in SHELBY, IOWA
From 11-DEC-10 13:00:00 to 12-DEC-10 01:00:00 (CST-6)
Reported by: AWOS

Blizzard conditions developed over Shelby county early in the afternoon of Dec. 11.  Snowfall over the county was generally 2 to 4 inches with a little over 3 inches reported in Harlan the highest reported in the county.  The snow combined with with northwest winds of 35 to 40 mph with gusts over 55 mph causing visibilities to frequently drop below 1/4 mile and to near zero at times.  A peak gust of 58 mph was measured by the Awos in Harlan at 535 pm.  The snow began around 8 am and light snow or significant visibility restrictions in blowing snow lasted until around 5 am on the 12th.

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

Blizzard conditions developed over Harrison county around noon on Dec. 11.  Snowfall over the county was generally 3 to 5 inches with 5 inches reported by the cooperative observer near Little Sioux.  The snow combined with with northwest winds of 35 to 40 mph with gusts around 55 mph causing visibilities to frequently drop below 1/4 mile and to near zero at times.  A peak gust of 53 mph was measured by home weather equipment in Mondamin at 555 pm on the 11th.  The snow began around 8 am on the 11th and light snow or significant visibility restrictions in blowing snow lasted until around 3 am on the 12th.

Blizzard in POTTAWATTAMIE, IOWA
From 11-DEC-10 13:00:00 to 11-DEC-10 21:00:00 (CST-6)
Reported by: AWOS

Blizzard conditions developed over Pottawattamie county early in the afternoon of Dec. 11.  Snowfall over the county was generally 2 to 3 inches with a little over 2 inches reported in Oakland the highest reported in the county.  The snow combined with with northwest winds of 35 to 40 mph with gusts to around 50 mph causing visibilities to frequently drop below 1/4 mile and to near zero at times.  The poor visibilities caused the closure of Interstate 80 east of Council Bluffs for 15 hours and also contributed to a 40-vehicle accident between Walnut and Atlantic.  A peak gust of 49 mph was measured by the Awos in Council Bluffs at 315 pm.  The snow began around 8 am and light snow or significant visibility restrictions in blowing snow lasted until around 2 am on the 12th.

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

Blizzard conditions developed over Monona county a little before noon on Dec. 11.  Snowfall over the county was generally 2  to 4 inches with 2.5 inches reported by the cooperative observer near Onawa the highest reported in the county.  The snow combined with with northwest winds of 35 to 40 mph with gusts around 55 mph causing visibilities to frequently drop below 1/4 mile and to near zero at times.  Poor visibilities caused a 40 to 50 car pile-up near the Woodbury county line on I-29 shortly before noon causing its closure.  Other highways in the county were also closed because of poor visibilities and drifting snow.  The snow began around 7 am on the 11th and light snow or significant visibility restrictions in blowing snow lasted until around 3 am on the 12th.

Blizzard in MILLS, IOWA
From 11-DEC-10 13:00:00 to 11-DEC-10 21:00:00 (CST-6)
Reported by: AWOS

Blizzard conditions developed over Mills county early in the afternoon of Dec. 11.  Snowfall over the county was generally 2 to 3 inches with around 2 inches reported in Glenwood the highest reported in the county.  The snow combined with with northwest winds of 35 to 40 mph with gusts to around 50 mph causing visibilities to frequently drop below 1/4 mile and to near zero at times.  A peak gust of 48 mph was measured by the Awos at Offutt AFB, just west of the county in Sarpy county Nebraska 548 pm.  The strong winds caused numerous power outages in the county, especially from 5 to 6 pm.  The snow began around 8 am and light snow or significant visibility restrictions in blowing snow lasted until around 2 am on the 12th.

Winter Weather in PAGE, IOWA
From 11-DEC-10 11:00:00 to 12-DEC-10 03:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Near-blizzard conditions developed over Page county for a few hours during the late afternoon or early evening hours of Dec. 11th.  Snowfall of an inch or two combined with northwest winds of 35 to 40 mph with gusts around 50 causing visibilities to drop to 1/4 mile or less for an hour or two.  A peak gust of 46 mph was measured by the Awos in Clarinda at 515 pm on Dec. 11.  Although visibilities improved a little in the early evening of the 11th, snow and blowing snow significantly reduced visibilities in open areas into the morning hours of Dec. 12th.

Winter Weather in MONTGOMERY, IOWA
From 11-DEC-10 11:00:00 to 12-DEC-10 03:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Near-blizzard conditions developed over Montgomery county for a few hours during the late afternoon or early evening hours of Dec. 11th.  Snowfall of an inch or two combined with northwest winds of 35 to 40 mph with gusts around 50 causing visibilities to drop to 1/4 mile or less for an hour or two.  A peak gust of 48 mph was measured by the Awos at Red Oak at 415 pm on Dec. 11.  Although visibilities improved a little in the early evening of the 11th, snow and blowing snow significantly reduced visibilities in open areas into the morning hours of Dec. 12th.

Cold/Wind Chill in MONONA, IOWA
From 11-DEC-10 23:00:00 to 12-DEC-10 08:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Northwest winds of 20 to 30 mph combined with temperatures which fell to around zero or a little colder and produced wind chill values of 20 below to 25 below zero from late on Dec. 11 into the morning hours of Dec. 12.