This is from sozobe's link: a painting by George Catlin, Mandan Rain Dance.
While visiting a pueblo we were told by the Indian tour guide that the ladders to the Kiva not only gave the direction ( north-south / east- west) by the uppermost step, but that the longer, pointed sides of the ladder are kind of a constant prayer for rain, the ends should catch the clouds.
There we saw a beautiful thunderstorm too. The sky was pitch-dark, black clouds seemed to reach the earth, thunder grumbled like freight trains or skittle alleys, and a horizon full of lightnings. No rain though.