In the last few days weather has changed from summer to fall. There is a crispness in the air, and tonight, August 29th, there is a prediction of snow. The photo at left is a summer storm. 
At right is Fireweed. This flower is common in burned areas and signals the regrowth that comes after the flames. Its bloom begins in August and as the flowers move up the stalk, we know fall is coming.
Another sign of late summer is the bison rut. The bulls rejoin the herd, grunting and following the females, fighting with bulls who come too close to their temporary female partner. This is the time of year we are apt to have them roam through out campground.
The wild raspberries are ripe. If Doug, the other photo guide, would please leave them alone, I'd be able to pick a handful instead of just a couple.
I've had good luck seeing and photographing some of the smaller wildlife this summer. This beaver was gnawing on willow branches at Fishing Bridge one evening last week.
I've seen more marmots this year than either of the other two years in the park. Am I just more aware, or was this a bumper year?
I was delighted to finally get a shot (only one decent one) of a short tailed weasel. I've seen weasels several times this year, but this morning he appeared among the rocks near my usual coffee break area on my photo tours. Some of my guests got better photos, but my camera is stored away for tours as I almost never shoot. But he was in the rocks long enough for me to get it out just before he took off. This small animal will turn white, except a black spot on its tail (almost invisible in this photo due to the shadow in the rock) for the winter. 
