Complex sentence: As soon as he perceived the imminent approach of bad weather, he would lie down on the ground and stick the blade above his head, before his spirit soared into the clouds to deal with the "ala".
Split into simpler sentences: As soon as he perceived the imminent approach of bad weather, he would lie down on the ground and stick the blade above his head. It was thought that his spirit then soared into the clouds to deal with the "ala".