For 90 seconds. And we didn't have transistors, heat sinks, complex resistors, or diodes, or insulative wires, overload protection, fuses, breakers, or amperage controllers, substation
energy banks, blow out fittings, or homogeneous metal wires. Those two flares blew out pulled copper wire strung on glass bells, exposed to open air, on a very unstable high amperage DC current. Radio signals would be the only temporary loss of significant valve, currently.
A later event, similar to its predecessor, York
city, they had these crazy towers called moon lanterns, antiqued street lights. They flickered for a couple seconds during that event. There are no mass scale examples of electric display. These things were fire hazards waiting to happen anyways, with
enough power flowing to them, to power an entire grocery store.
Isolated examples do not represent the whole.