Dear God.
Tragic! My condolences to all the families!
That photo is of a New Zealand crash on January 12, 2014.
The balloon apparently made contact with a power line, caught fire, broke free, ascended, and then came back down after the burning balloon lost lift.
Drudge's image is the last of a series. You can see some of the rest here.
The current balloon definitely ended up at a power line. So, the most likely hypothesis is that the fire resulted from contact with the power line.
I heard a balloon pilot interviewed in the current case. He had only just heard about it and couldn't offer specifics. But he was horrified that anyone would go up with 16 people. He said it's much harder to pilot a heavy balloon because the balloon's response to heat input is much slower.