Iowa DOT News Release



Frigid temperatures hamper Iowa DOT's efforts to clear roads

Posted on: February 19, 2008

AMES, Iowa – The Iowa Department of Transportation (Iowa DOT) maintenance forces have been working continuously in many areas of the state to bring roads to normal winter driving condition. The recent heavy snow, wind and low temperatures are hampering those efforts in eastern and northeastern Iowa.

The warmer temperatures Sunday afternoon caused melting that refroze on Iowa roadways over night into Monday. High winds continue to blow snow across the roadways where warm vehicle tires are bonding blowing snow to the surface. The ice build-up then creates slippery areas on the roadway making travel difficult. 

The Iowa DOT has been using ice blades on maintenance vehicles and applying sand and sand/salt mixes, but the effectiveness of deicing chemicals is greatly diminished by low temperatures. It takes 12 times as much salt to melt a pound of ice at zero degrees Fahrenheit compared to 30 degrees Fahrenheit. When the temperature dips below zero, salt is no longer effective to melt ice.

Temperature oF

Pounds of ice melted per pound of salt

30

46.3

20

8.6

10

4.9

0

3.7

-6

negligible

Pavement temperatures are expected to warm up to about 20 degrees today for a short period of time and winds are likely to diminish somewhat, but that may be little help to clear icy roads.

The Iowa DOT will continue efforts to improve roadway conditions, but motorists are urged to exercise patience, evaluate the necessity of each trip, check local weather forecasts and road conditions, and carry appropriate supplies if a trip is deemed necessary.


Iowa highway in the evening