Moreover, this collapse is a complete mystery. It's had several recent inspections by different groups without finding anything suggesting a collapse. The things that were found were repaired. That may be the worrisome problem - the bridge doesn't appear to have been neglected or in bad shape, and nobody yet knows what to look for in other bridges to prevent this.

Another odd thing is that it didn't buckle somewhere and fall: the two ends failed simultaneously. How does that happen?

It's going to take a while to get anywhere near the cause of this. The river isn't that deep there but it's still going to be a big job to pull all of the debris up and go through every joint and support member. Until then you might as well ask Taylor Rain for her analysis.