Hey I was up there with my out-of-shape dad on Saturday too and was just above Anvil Rock when the lightning really started. Up till then the entire pack train was buzzing as everybody's ice axes and pickets became lightning rods, but I wasn't concerned until my hair started standing up . There were like three huge flashes of lightning with thunder cracks that were nearly simultaneous, so that means like less than 400 yards away. Almost everyone turned around then, if they weren't already turned off by the hail and snow. I've never been that exposed in a thunder storm and it scared the hell out of me, a feeling that was accentuated by the never-ending whine of the electrons harmonzing with my ice axe. Good snow conditions and a quick descent though.