We passed several ranches. Along in the middle of the morning thunder began to growl in the hills, and we knew that we were liable to be wet.
The valley grew narrower, as if it was to pinch out, and the thunder grew louder. The storm was rising black over the hills ahead of us.
"That's going to be a big one," said Fitz.
It looked so. The clouds were the rolling, tumbling kind, where drab and black are mixed. And they came fast, to eat the sun.
It was raining hard on the hills ahead. We could see the lightning every second, awful zigzags and splits and bursting bombs, and the thunder was one long bellow.
The valley pinched to not much more than a gulch, with aspens and pines and willows, and now and then little grassy places, and the stream rippling down through the middle. Half the sky was gone, now, and the sun was swallowed, and it was time that Fitz and I found cover. We did not hunt a tree; not much! Trees are lightning attracters, and they leak, besides. But we saw where a ledge of shelf-rock cropped out, making a little cave.
"We'd better get in here and cache till the worst is over," proposed Fitz. "We'll eat our lunch while we're waiting."
That sounded like sense. So we snuggled under. We could just sit up, with our feet inside the edge.
"Boom-oom-oom!" roared the thunder, shaking the ground.
"Boom-oom-oom! Oom! Oom! Boom!"