National Weather Service United States Department of Commerce

Snowstorm and Blizzard of December 8-9, 2009


A long-lived storm system brought heavy amounts of snow to the region Tuesday and Wednesday December 8-9th.  In addition to the heavy snow, blizzard conditions spread over much of the area Wednesday. Snowfall was heaviest from southwest Iowa through southern Wisconsin, where amounts of 12 to 15 inches were common. Significant snows were also found farther south, through the Quad Cities and southeast Iowa, where amounts ranged from six inches to upwards of one foot.

Early on Tuesday the 7th, the developing low pressure spread light snow across eastern Iowa, northwest Illinois, and northeast Missouri. Accumulations by the afternoon were less than an inch east of the Mississippi River, around 2 inches along the river, and 3+ inches across portions of east central Iowa. At this time, warmer air aloft began to wrap around the low pressure, which was located in central Missouri. This resulted in a change to mixed precipitation (snow, sleet, and freezing rain) along and east of the Mississippi. Western Illinois changed to all rain, with Macomb totaling over a half inch of liquid. Farther northwest, freezing rain coated elevated surfaces with anywhere from 0.10" to 0.30" of ice along a line from Burlington, IA to Sterling, IL. To the northwest of that line sleet was common, even being reported as far west as Cedar Rapids. However, across east central Iowa, northeast Iowa and extreme northwest Illinois the precipitation remained all snow. This included reports of thundersnow in Vinton, IA and Ridott, IL as the low pressure began to strengthen rapidly in the vicinity of Peoria, IL.

This rapid deepening was observed with pressures falling at greater than 1 mb/hr in the center of the low. By late evening light snow showers or freezing drizzle were common south of I-80, as a dry slot pushed into that area. Meanwhile, heavy snow continued across the Highway 20 corridor. As midnight approached and the storm center neared Chicago, the heavy snow band began to work back across eastern Iowa. Up to this point snow totals ranged from nothing in western Illinois, to 5 inches in the Quad Cities, to almost 10 inches in east central Iowa.

Early Wednesday the 8th, the low pressure was continuing its explosive strengthening, and air began to rush towards the center. This meant strong winds out of the north, then northwest, began to blow across eastern Iowa. Sustained winds between 25 and 35 mph, with higher gusts, started to blow and drift the freshly fallen snow. Meanwhile, heavy snow continued in a band from east central Iowa, through the Quad Cities, and up into northwest Illinois and southern Wisconsin. By late morning blizzard conditions were being felt across most of the upper Midwest. It was no different throughout eastern Iowa, northwest Illinois, and northeast Missouri. In rural areas blowing and drifting was widespread, with frequent whiteout conditions common, especially west of the Mississippi River. All the while heavy snow continued to further restrict visibility. Despite the storm being over northern Lower Michigan these winds and the snow continued into the early evening. Final accumulations ranged from as little as 1 inch, to over 15 inches, and are included below. As one final display, the departing storm also brought down bitterly cold air into the region. The airmass blasted through, dropping temperatures from near 32 degrees at midnight, to the single digits by Wednesday afternoon.


Visible Satellite Image (Thursday 12/10/9). 
White areas show snow.
Estimate of Iowa Snow Totals Estimate of Illinois Snow Totals

  Area Snowfall Amounts

 INCHES  LOCATION                 ST  COUNTY         
 ------  -----------------------  --  ------------ 
 15.3    BRIGHTON                 IA  WASHINGTON     *official observation
 15.0    3 NW MT VERNON           IA  LINN             
 15.0    FREEPORT                 IL  STEPHENSON     
 14.0    PEARL CITY               IL  STEPHENSON     
 13.5    E SOLON                  IA  JOHNSON        
 13.3    VINTON                   IA  BENTON         
 13.0    3 N STOCKTON             IL  JO DAVIESS     
 13.0    4 WSW STANLEY            IA  BUCHANAN       *official observation   
 12.5    S MOUNT AUBURN           IA  BENTON        
 12.5    SSE ATKINS               IA  BENTON        
 12.5    1 SSW BELLE PLAINE       IA  BENTON        
 12.5    W ELIZABETH              IL  JO DAVIESS    
 12.0    2 NW MARION              IA  LINN          
 12.0    VICTOR                   IA  IOWA          
 11.9    DAVENPORT MUN. AIRPORT   IA  SCOTT          *official observation
 11.6    1 NW CEDAR RAPIDS        IA  LINN          
 11.5    WNW PARNELL              IA  IOWA         
 11.0    CASCADE                  IA  DUBUQUE        *official observation
 10.8    5 NW CEDAR RAPIDS        IA  LINN         
 10.5    LOWDEN                   IA  CEDAR          *official observation
 10.5    DUBUQUE AIRPORT          IA  DUBUQUE        *official observation
 10.0    3 W SUNBURY              IA  CEDAR          
  9.0    ANAMOSA                  IA  JONES          
  9.0    5 NNW LANARK             IL  CARROLL        
  9.0    4 E WHAT CHEER           IA  KEOKUK         
  8.5    CEDAR RAPIDS             IA  LINN            
  8.5    4 NW STERLING            IL  WHITESIDE       
  8.4    MOLINE QUAD-CITY AIRPORT IL  ROCK ISLAND    *official observation
  8.1    ERIE                     IL  WHITESIDE      
  7.2    CORDOVA                  IL  ROCK ISLAND    
  7.0    2 E BECKWITH             IA  JEFFERSON     
  7.0    1 N BURLINGTON           IA  DES MOINES    
  5.5    1 SE PRINCETON           IL  BUREAU        
  5.0    W CANTRIL                IA  VAN BUREN       
  3.9    MALDEN                   IL  BUREAU          
  2.0    ESE MONMOUTH             IL  WARREN          
  1.0    1 SSW MACOMB             IL  MCDONOUGH      

Though the snowfall totals listed above are impressive, did you know that a blizzard has nothing to do with the amount of snow you measure? The official definition of a blizzard is, "winds of 35 mph or more with snow and/or blowing snow reducing visibility to less than 1/4 mile for at least 3 hours."

The pictures below provide a snipet of what conditions were like for the evening shift, as they showed up to work on Wednesday afternoon.


 A heavy, wet snow had coated almost everything in sight the night before, and now was frozen in place.

Heading to the front door is a chore with west winds blowing straight down the walkway.

 A newly installed snow fence was doing its job, keeping the entrance to the parking lot (relatively) snow free.

 A far larger snow drift had piled up by the snow fence protecting the entrance to the airport road, as the sun began to peek through the heavy snow squalls.

 Across the wind swept field less than 100 yards north of the office, the weather balloon inflation building suddenly seemed very far away.


The above pictures were taken standing in the same location, at roughly 2pm, 24 hours apart. On the left is the field west of the office on Thursday afternoon, with the Davenport Municipal Airport terminal buildings in the distance. The buildings are a little over 500 feet away. On the right is the same photograph taken on Wednesday afternoon, during some of the worst blizzard conditions. The grass only a few feet away is greatly obscured, and with some really good eyesight one can make out the ghostly sillouette of the airport signal tower. This is just an example of conditions experienced across most of the forecast area.