It went quiet because a breaker did operate, but only once there was

enough ionisation from the fire to allow an arc between phases or from

phase to ground. Perhaps a few hundred amps? Which is a few megawatts,

maybe 1000 homes?

Nope. Definitely a couple of hundred thousand. I should, however, point out that this was back in the late 70s, so it's possible they've reduced the voltages these lines are permitted to carry since then.