From the picutres it doesn't look smoke but only the different colour of the mountain ridge.
Said that I'am really shocked with this incident and I think that there are some elements that can already give us an idea of a scenario. I think that it's plausible to assume that they probably try to cross the pass to the north but maybe were not at the correct altitude (8700 ft) and decide to continue straight ahead to gain altitude or make a 180° left turn which led to a stall.
For me there are some elments which have to be verified, like pilot incapacitation, technical problem and/or fuel leak, but it's really clear that the vertical impact at high speed, it's the consequence of a stall.
