authorities have said an underground electrical fire is blamed for an explosion that sent a manhole cover flying more than 200 feet .
the fire began around 11:30 a.m. sunday on tupper street in downtown buffalo , new york .
police evacuated two buildings as smoke came out of manholes .
a photojournalist was interviewing a man on the street when the second blast occurred about a half-block behind him and the manhole flew up .