Sometimes there is nothing you can do to foresee how the weather will turn. Still, the fact that you know the weather can try to kill you is all the information you need to get prepared. On that venue, decision points begin way before you get yourself into a dicey situation. If you are improvising as opposed to executing plan B (or C, or D), it should be a clear warning signal that you were not prepared.
Here in northern Japan the Hakoda Mountains get the end tail of Siberian snow storms, which is great for accumulation but not so great when you get stuck on them. One morning we started walking from the top of the gondola when the wind began to pick up. In 15 minutes it went from being able to see blue sky, to hurricane-force winds and zero visibility beyond 10 feet. It took me about 45 minutes to crawl 500 meters on my hands and knees, dragging a snow board that was pulling me in the opposite direction. I had snow shoes, I knew the mountain and best/worst exit routes, I had layers, a poncho, tons of empty calories, and plenty of options. It wasn’t a walk in the park but at no time I felt like I was about to die.
Miguel, where in Japan are you? I’m in Misawa, Aomori Ken.