An ice-storm grips much of the Chicago area away from Lake Michigan as Thursday dawns. Tree limbs and power lines droop under the added weight of ice and are at risk of snapping as powerful winds with a mammoth winter storm whip through the region. Ice storms occur when warm, moist air moves into an area above a shallow layer of freezing or sub-freezing air. Temperatures have hovered in the upper 20s or low 30s at ground level over much of the area overnight while readings just 2,000 feet above the ground have surged into the mid 40s. It's a set-up which has allowed rain to form in the warmer clouds above which then falls into cold surface air below producing a glazing of ice on colder outdoor surfaces. Though road chemicals work well at these temperatures, ice can accumulate on untreated sidewalks, driveways, vehicles and other cold outdoor surfaces and extreme caution is advised when first encountering any surface exposed to the freezing rain.
Power outages were scattered across Rockford late Wednesday evening and flooding was being reported as water pooled near snow-clogged drains. At the same time, a third of an inch of ice covered most surfaces from Portage and Valparaiso in Indiana west to the Mississippi River. Numerous traffic accidents were reported. The Chicago Skyway had to be closed for salting after a multi-car pile-up occurred on the icy thoroughfare and accidents at I-88/I-294 intersection near Oak Brook resulted in injuries. An ice build-up on Willis Tower interfered with NOAA Weather Radio transmissions which emanate from the antenna array there. And at Portage Indiana, the ice accumulation at had reached 0.4 inches late Wednesday evening and there was concern power lines stressed by the ice and wind were at risk.
Weather troubles may only be beginning in the Chicago area--the next concern is flooding. Rainfalls of nearly 2 inches are predicted Thursday afternoon and night as temperatures rise above freezing. The melting snowpack, which contains 0.75 to as much as 3.25 inches of water, along with run-off from wind-driven downpours may send an unmanageable amount of water into area waterways inducing flooding.
Storm's grip on area to be a long one as system loops over Iowa in coming days
In a peculiar twist, computer models slow the massive storm's center over Iowa Friday and Saturday, rotating it in a circular manner over the state. This is to slow the storm's exit from the Midwest and means snow accumulations may grow extreme from sections of east and central Nebraska northeast into eastern South Dakota, northwest Iowa and Minnesota. Accumulations in hardest areas there may top 20 inches. Forecast models ultimately bring the cold pool of air above the storm eastward over Chicago this weekend and suggest significant snow accumulations aren't out of the question here. Early estimates suggest as much as 2 to 6 inches of snow may occur--though these figures must be viewed as preliminary and subject to update.
Power outages were scattered across Rockford late Wednesday evening and flooding was being reported as water pooled near snow-clogged drains. At the same time, a third of an inch of ice covered most surfaces from Portage and Valparaiso in Indiana west to the Mississippi River. Numerous traffic accidents were reported. The Chicago Skyway had to be closed for salting after a multi-car pile-up occurred on the icy thoroughfare and accidents at I-88/I-294 intersection near Oak Brook resulted in injuries. An ice build-up on Willis Tower interfered with NOAA Weather Radio transmissions which emanate from the antenna array there. And at Portage Indiana, the ice accumulation at had reached 0.4 inches late Wednesday evening and there was concern power lines stressed by the ice and wind were at risk.
Weather troubles may only be beginning in the Chicago area--the next concern is flooding. Rainfalls of nearly 2 inches are predicted Thursday afternoon and night as temperatures rise above freezing. The melting snowpack, which contains 0.75 to as much as 3.25 inches of water, along with run-off from wind-driven downpours may send an unmanageable amount of water into area waterways inducing flooding.
Storm's grip on area to be a long one as system loops over Iowa in coming days
In a peculiar twist, computer models slow the massive storm's center over Iowa Friday and Saturday, rotating it in a circular manner over the state. This is to slow the storm's exit from the Midwest and means snow accumulations may grow extreme from sections of east and central Nebraska northeast into eastern South Dakota, northwest Iowa and Minnesota. Accumulations in hardest areas there may top 20 inches. Forecast models ultimately bring the cold pool of air above the storm eastward over Chicago this weekend and suggest significant snow accumulations aren't out of the question here. Early estimates suggest as much as 2 to 6 inches of snow may occur--though these figures must be viewed as preliminary and subject to update.
