Cracked Windshields @ DEN

On my flight back from San Francisco, our flight was delayed for about 2 hours in Denver due to a cracked windscreen. The Denver Post reported that there wasn't a good explanation for the cracked windshields. Our gate agent told us that it was gravel damage from the high winds, and it seemed at the time like it would be pretty high winds to take a piece of gravel 25 ft in the air and smack it into the windshield of an airliner with enough force to crack the glass. Weird.

(Quoted from the Denver Post)

The National Transportation Safety Board said its glass specialist will examine 22 damaged front and side windshields that were removed from affected airplanes, investigator Jennifer Kaiser said.

Wind gusts of up to 50 miles per hour were recorded at the airport and there were rapid temperature changes and some snow Friday afternoon when airlines reported the cracked windshields.

Kaiser said the NTSB is also investigating whether an air pressure change may have contributed, she said.

DIA spokesman Chuck Cannon said airport operations and maintenance employees could offer no explanation for the windshield problems. "It's baffling," he said.

SkyWest Airlines, a regional carrier for United Airlines, reported nine planes suffered windshield cracks, while Frontier Airlines said four of its aircraft suffered similar damage. One plane from Great Lakes Airlines suffered a cracked windshield, Kaiser said.

NTSB's Kaiser confirmed that there were no reports of impact from flying debris.

I wonder how much a new windscreen costs - I would guess something on the order of $6000-$9000 for a new plexiglass or acrylic panel. Anyone know?