There is a street light I pass frequently that occasionally flashes like a strobe.

I've seen a bright flash at that corner a number of times over the past year or two, but never saw the source. Usually there's a building blocking it and all I see is the street light up.

This past week I was coming from the other direction and clearly saw the street light flash twice, very brightly.

These lights are bluish white, I've always assumed they were mercury vapor, but don't really know. It's not a city likely to have moved to LED.

Is there a failure mode for a discharge lamp that would produce that?