The westbound span of the Chesapeake Bay Bridge reopened at noon Tuesday, after a painting reported feeling "unusual vertical movement" of the bridge shortly after midnight.
Both spans of the bridge were closed overnight for scheduled cleaning, but only the eastbound span opened in the morning.
Inspectors have now determined that a massive tarp was responsible for catching the wind, causing the span to move more than unusual, NBC4's Darcy Spencer reports.
The tarp was being used to catch debris as the crews worked. Officials were unable to say exactly how large the tarps were, but they covered the towers. Such tarps will no longer be used on the bridge.
While suspension bridges always have some movement, what the workers observed was more intense than that. Officials said it moved more than the level of acceptance but did not specify how much that is, Spencer reported.
The bridge didn't suffer any structural damage, officials said.
During the closure, officials alternated traffic on the eastbound span so that drivers could cross safely in each direction.
You can call 877-BAYSPAN (877-229-7726) for current traffic conditions at the bridge. Traffic appeared to be normal going into the Tuesday afternoon rush, Spencer said.