Last night there were three. They must be loud–I can hear them very clearly all the way from Powderhorn Park. But this blogger, who lives a couple of blocks away from the river, has been following the explosions more closely than I have. Apparently the Minneapolis Bomb Squad is on the case…I, however, am not convinced that they’re bombs.
One thought I’ve had is that sound travels farther at night due to a lack of interfering noise. The difference between night and day is especially noticeable in the city, where the constant traffic provides a white noise during the day that we tune out because our brains are used to hearing it. In fact, 35W runs through South Minneapolis, and even if you can’t differentiate the sounds of individual cars, it’s always there in the background. At night, when there is almost no traffic, there is almost no interfering noise and sound can travel farther. Besides that, the cooler and denser air at night is a better medium for sound to travel in–something you can read more about here.
To my ear, the sound is almost like that of two large pieces of metal hitting each other, which led me initially to think that maybe it was a river barge docking, or hitting another barge–something that makes sense given the what the first blogger said about the sound occurring at regular times. Or maybe it’s train cars coupling and decoupling, as suggested by someone on the Twin Cities Daily Planet blog.
Or, maybe, it’s none of the above.