A powerful storm system moved into the southwest U.S. on January 31st into the 1st  The system moved east-northeast across the southern U.S. on the 1st into early the 2nd.  Surface low pressure developed over west Texas.  The low tracked across Arkansas and eventually through the Ohio River Valley.  A considerable amount of moisture was drawn north into the storm system.  A very large shield of precipitation developed to the north of the low pressure track.  The main deformation zone was nearly 4 degrees wide, covering a large part of the mid section of the country.  Snow spread north into Iowa during the afternoon of the 1st and picked up in intensity rapidly during the late afternoon and early evening hours.  The low pressure system deepened rapidly as well.  A strong pressure gradient was in place over the state.  As the low crossed extreme southern Illinois, the pressure dropped to about 995 mb.  At the same time a high pressure of nearly 1050 mb was located over western North Dakota.  Winds increased rapidly during the evening with sustained winds of 25 to 35 MPH across most of the state.  Winds gusted to around 50 MPH over the southeast half.  The combination of falling snow and strong winds dropped visibility to less than 1/4 mile for several hours.  Whiteout conditions were reported in many rural areas.  Roads became impassible in places, and treacherous everywhere.  Several highways were closed, however most of the main highways remained open, including Interstate 80.   Numerous businesses and nearly all schools closed by the afternoon of the 1st and remained closed on the 2nd.  Snowfall of 6 inches or more occurred over about the southeast half of the state, with accumulations in excess of 8 inches over the southeast third.  The heaviest accumulation in the Des Moines CWA was 12.3 inches in the Centerville area of Appanoose County.  In Monroe County, 11.9 inches was reported in Albia with 11.4 inches falling around Allerton in Wayne County. In Poweshiek County 10.9 inches of snow was recorded at Grinnell.  The heavier snow accumulation over southeast Iowa was in part the result of convection.  There were numerous reports of thundersnow from Ottumwa north toward the Grinnell area.  This is the same event also listed in Stormdata as the 01 February Winter Storm for southwest into west central Iowa.

Blizzard in RINGGOLD, IOWA
From 01-FEB-11 17:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in DECATUR, IOWA
From 01-FEB-11 17:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in WAYNE, IOWA
From 01-FEB-11 17:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in APPANOOSE, IOWA
From 01-FEB-11 17:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in DAVIS, IOWA
From 01-FEB-11 17:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in UNION, IOWA
From 01-FEB-11 17:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in CLARKE, IOWA
From 01-FEB-11 17:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in LUCAS, IOWA
From 01-FEB-11 17:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in MONROE, IOWA
From 01-FEB-11 17:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in WAPELLO, IOWA
From 01-FEB-11 17:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in MADISON, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in WARREN, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in MARION, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in MAHASKA, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in DALLAS, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in POLK, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in JASPER, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in POWESHIEK, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in BOONE, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in STORY, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in MARSHALL, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in TAMA, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in GRUNDY, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in BLACK HAWK, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in BUTLER, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in BREMER, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Blizzard in HARDIN, IOWA
From 01-FEB-11 19:00:00 to 02-FEB-11 02:00:00 (CST-6)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Official NWS Observations