??
The aeroplane doesn't know it is going up or down, only AoA on the wings. If you fly at max alpha in calm conditions, you might climb at 1000 fpm. If the air is decending at 1000 fpm the net climb AGL is zero and if the air is going down at 2000 fpm, then you have a net 1000 fpm decent...right?
Through that parcel of air you are still moving forward at your same forward speed, which in the Barons case is a minimum of 73 kts if still flying. If not flying then it is stalled. It is possible that the aeroplane stalled into this ridge as a result of a down draft as the pilot trying to outclimb it (panic at seeing the ridge, yank back maybe?). Seems like it has happened to some famour pilots over the years. But over the peak of a mountain you normally find rising air. The descending air is to be found in the lee. To impact a ridge with high VS then the aeroplane must have been above the ridge to start with, either that or he cleared the ridge then stalled it and fell onto the ridge........which is why I don't think weather conditions were a factor in this.
Looking at the pics, the aeroplabne obviously hit in a nose down attitude. Due to the extent of the damage it doesn't look like a "just cleared the ridge, panic, stall" to me, but a fall from some considerable height. The fact the wings haven't sheared off is a mystery and indicates a low forward speed, as does the fact the engine blocks are still in the vicinity of the aircraft final resting place.
Just my view, I may well be wrong but that is how I interpret what I am seeing.