Impact of the February 1-2 Storm on Highways

The impact of the February 1-2, 2011, storm on highways in Illinois was significant. Using snowfall data and Illinois DOT highway data, our GIS specialist Zoe Zaloudek was able to calculate the number of miles of interstate, US highways, and state roads covered by selected amounts of snow.
Below is the resulting map showing both the roads and significant snowfall. A table at the bottom of the map shows the number of miles affected by 6, 8 and 12 inches or more of snow. The impacts were felt all the way from Quincy to Chicago. We chose a starting point of 6 inches as the threshold for significant disruption of traffic and higher removal cost, based on earlier studies in Illinois.
For example, about 1,132 miles of interstate roads in Illinois received 12 inches or more of snow. Including 1,762 miles of US highways and 4,099 miles of state roads, it adds up to an incredible 6,993 miles of roads with a foot or more of snow to plow.
These estimates do not include the thousands of miles of county roads as well as city streets and alleys in the Chicago metropolitan area and elsewhere. However, we did not have a complete database of those road systems. Also roads covered by less than 6 inches of snow were treated as well for additional costs.

February blizzard affect roadways
The number of miles of Illinois roadways affected by selected amounts of snowfall during the February 1-2, 2011, winter storm.

Snowfall Totals from around Illinois

The winter storm of February 1-2, 2011, will be remembered by many in northern and central Illinois. The National Weather Service (NWS) did an excellent job of producing forecasts and warnings on this storm. In the aftermath, we have began collecting the snowfall measurements from a variety of networks. Rather than list all the data here, I have provided some links to data sources.
Snowfall totals and some maps provided by NWS offices are available here:

Here is a preliminary look at snowfall totals across the Midwest. Snowfall amounts in excess of 12 inches extend from Oklahoma, into Missouri, the northern half of Illinois, and on into northern Indiana and southern Michigan.

Experimental Hour Snowfall Analysis
Preliminary snowfall totals map for the February 1-2, 2011 storm (NWS image).

And zooming in on northern Illinois.
Snowfall totals for the February 1-2, 2011, event in northern IL (NWS image).

Tornadoes Strike Illinois in November

Severe weather, including   four tornado reports, struck northern Illinois on November 23, 2010. According to NOAA’s Storm Prediction Center:

  • a tornado was spotted 4 miles east of Loves Park (Boone County); power lines down and debris were reported;
  • a second tornado report from 3 miles east of Loves Park (probably the same tornado) caused 3 injuries, nearly destroyed one business, and damaged other homes and a garage;
  • a tornado was spotted on the ground 2 miles northwest of Harvard (McHenry County); no damage was reported;
  • a tornado was spotted in McHenry County, right on the Illinois-Wisconsin line, 5 miles southeast of Walworth WI; apparently all the damage occurred in Wisconsin.

Besides tornadoes, high winds caused extensive damage including tree limbs and power lines down, damage to buildings, and trucks blown over. The link to the full report is here.
The NWS offices at Davenport IA and Chicago IL are conducting damage surveys. Results will be posted here:

Satellite View of Midwestern Storm

NASA has posted low and high resolution satellite photos of the record-setting low-pressure system that rolled through the Midwest last week. They say:

The storm that swept across the center of the United States on October 26 and October 27, 2010, was memorable to those who experienced it because of its strong winds, rain, hail, and widespread tornadoes. Meteorologists get excited about the storm because it set a record for the lowest pressure (not associated with a hurricane) measured over land in the continental United States. At 5:13 p.m. CDT, the weather station in Bigfork, Minnesota recorded 955.2 millibars (28.21 inches of pressure). Pressure is one indicator of a storm’s strength, and this measurement corresponds to the pressure seen in a Category 3 hurricane.

You can read the full story and see the images here.

Satellite view of Midwest storm of late October 2010
Satellite view of Midwest storm of late October 2010 (NASA).

Record Low Pressure on Great Lakes Storm

According to the National Weather Service

New record set today for the lowest pressure in a non-tropical storm in the mainland U.S. The massive storm system barreling across the central U.S. had a minimum central pressure of 28.24″ or 956 mb (equivalent to the minimum pressure of a Category 3 hurricane). This breaks the old record of 28.28″ (958 mb), set on Jan. 26, 1978, during the Blizzard of 1978 (aka the Cleveland Superbomb). This is also lower than the March 1993 Superstorm (aka “The Storm of the Century”), or the “Witch of November” storm that sank the Edmund Fitzgerald in 1975, or even the Columbus Day Storm of Oct. 1962.