strategic city. it s a massive offensive. thousands of kurdish perg mehera fighters are leading the charge. plumes of smoke blacken the skies as coalition bombs target from the air. the strategy is attack the city from three sides. our senior international correspondent nick paton walsh is on the ground for us in iraq. he s very near to this whole sinjar area, closely following what s going upon nick, describe what you have seen because i understand it is very dramatic. from the early hours this morning, wolf, we saw an enormous column of peshmerga we followed around towards the west of the city. that s key because it seems that s where much of the advance today were made by them. their main objective, the peshmerga want to retake sinjar, want to reverse what happened to the yazidi population that happened last year when isis