There is some rather extreme flooding going on in the Yellowstone River valley right now. To give a sense of it, the AP has reported the river cresting at 13.88 feet at Corwin Springs, Montana, while the previous record high water was 11.5 in 1918. I’ll admit that, while I read about the flooring this afternoon, I hadn’t paid much attention until I saw this:
I’ve written here about any number of old bridges being destroyed by floods. That’s what it looks like. That was the Carbella Bridge, a 1918 steel truss with a span of 175 feet over the Yellowstone River. (Note that Bridgehunter updated the status to “lost” the same day that the event occurred.) The formal description: it was a pin-connected Pratt through-truss with a camelback profile and built-up chords. It was put on the National Register of Historic Places in 2010, at least in part because it was the last remaining example of a standard bridge type that had been built by the state. The NRHP nomination form identifies that type as being used between 1890 and 1915, while this bridge was constructed in 1918 as the last of the type. And 1918 was also the date of the previous record flood, but there was no previous bridge at the site, which is what I was expecting. This bridge was built to accommodate car traffic, parallel to an older railroad bridge. A report has debris from the bridge found 35 miles downstream, which gives a sense of the force of the floodwater.
Obviously (a) any casualties are far more important than the loss of a bridge and (b) it’s not like this was a unique monument. Fortunately, so far, reports of injuries are few and there are no reports of deaths as of now. As for (b)…the demolition of every Montana truss bridge on this model made sense in itself – functional obsolescence, changes in traffic patterns, maintenance costs – until you wake up one day and realize that there’s only one left. And a natural disaster – and on the scale of such things, a relatively small natural disaster – is enough to destroy that one and now you’ve got nothing. We are careless with our built heritage.
In happier days: