Looks like a reverse snowball's trajectory. I'd like to hear that film in "reverse" to see what the sounds are like, although I'd suspect that
was only wind for sound.
That is no ufo, that is just ash-flakes being caugh in the upward drift of hot air from the volcano. We all know that hot air rises right? The ash is
what is naturally created at the top layers of a active volcano over time.
Although the ash idea is pretty good and It does appear to be drifting with the wind.. That thing is gaining altitude very fast and not slowing down.
I say ufo
Given the distance the footage is being shot from, along with the fact that the camera pans quite far up above the volcano (even considering the
footage is zoomed in) and the object is still visible rules this out.
Also, is this volcano even active? There's a lot of snow on there. Thanks for offering a possible explanation though.