Winds clocked at more than 80 m.p.h. ripped down nine 45-ton concrete girders on a highway overpass under construction Saturday, injuring two people slightly when their vehicles smashed into the rubble, officials said.
No one was under the bridge when the first four of the 100-foot girders fell, police spokesman David Grimm said.
The cab of one vehicle, a Safeway Stores bread truck, was badly damaged but rescuers got the driver out before the other five girders came crashing down, Grimm said. The other vehicle was a car. Both drivers were released after hospital treatment.
A 105-m.p.h. wind gust was reported in the Boulder area several minutes before the first girders fell, said Keith Williams of the National Weather Service. The bridge was near the northeast city limits. Williams said the highest gust recorded in Boulder early Saturday was 84 m.p.h.
Girders Lifted Off Pads
Dan Hopkins, state Highway Department spokesman, said the winds "lifted the concrete girders off their bearing pads."
The Colorado State Patrol said the wind also knocked over a mobile home and a tractor-trailer on Interstate 70 in the foothills west of Denver, where there also were reports of cars being blown off the highway.
Wyoming's Highway Patrol closed all but three highways in the state's southeastern corner when wind gusting to more than 50 m.p.h. whipped up blizzards and reduced visibility to zero in some areas. That combined with icy roads to contribute to numerous accidents, the patrol said.
The Chinook winds were clocked at 120 m.p.h. at Miles Peak, Colo., near Berthoud Pass, and at 92 m.p.h. at Jefferson County Airport, southwest of Denver. "It destroyed the anemometer at Jefferson County Airport," said Lyle Alexander of the weather service.
The advancing cold front brought subzero temperatures to the upper Mississippi Valley.
As late as noon Saturday, the weather service reported readings of zero at Jamestown, S.D., and Warroad, Minn., and 3 below at International Falls, Minn.
Colorado Coldest Spot
The nation's cold spot Saturday was Gunnison, Colo., with a low temperature of 20 below zero.
Snow extended over the northern plains and Minnesota and freezing rain mixed with snow fell across Nebraska.
In Boulder, the overpass project began Aug. 17 but had been closed for the winter since late October. Hopkins said the collapse would not delay completion of the project, scheduled for next summer.
"We'll have new girders on site by the time construction resumes this spring," he said.
Hopkins said the girders cost $8,000 to $10,000 each. He could not estimate the cost of the labor to replace them on their supports.
He said the winds also tore down "several traffic light signal heads and blew in several windshields."
The collapse temporarily closed Highway 119 from Boulder to Longmont.