[r9etb]

That's a bizarre photo. What the heck would cause damage like that to a highway bridge? Every other section of bridge structure has been lifted out of place

FWIW, each of the sections is built independent of the next, which explains why some sections survived and others didn't. Don't know what caused the sections to tip, but the amount of debris on the bridge deck seems to indicate a pretty significant current, so perhaps the water simply lifted the roadway right off the piers.

[Alberta's Child]

As I think about it, it occurs to me that the bridge was built out of alternating "fixed end" and "bearing" sections. Bridge structures have expansion joints that permit each segment to expand and contract as the temperature changes. A concrete slab can be fixed at one end and slide freely on a bearing plate at the other end, or it can slide freely on a bearing plate at both ends.

It looks like the bridge was built with alternating sections of fixed (F) and bearing (B) ends like this (where the "/" denotes a gap between adjacent sections):

[ABUTMENT] F---B / B---B / F---B / B---B / F---B / B---B / B---F [ABUTMENT]

The "B---B" sections would have been more susceptible to lifting action of wind and waves, since they are only held in place on the bearing plates by the sheer weight of the concrete.