No wonder it was so loud! The sidewalk was completely shattered from below!
Thanks to all the readers who responded, especially in the immediate aftermath. Many of you have expressed your frustration at not being able to find any news about this, so I'm glad I was able to at least create a space to share information.
Reader David also noted that here may have been two additional explosions on Classon at Myrtle-Willoughby yesterday (via Gothamist Labs).
Is this a common occurence? The blast was loud and frightening on Friday night. The authorities seemed to know in advance that it would happen -- firetrucks were lining Washington immediately afterwards. But still. Someone walking past could have been seriously injured. It doesn't seem fair that there was no communication with the neighborhood from ConEd, etc, aside from the residents whose homes had to be searched before and after the blast.