For those who see the national parks as being preserved time immemorial under gigantic bell jars, there is evidence that each succeeding generation makes an imprint or two on the parks. It wasn't too terribly long ago, for instance, that you climbed into the bleachers to watch the bear buffets in Yellowstone National Park, or that the El Tovar Hotel at the Grand Canyon National Park had separate dining areas for men and women.

There is perhaps no more ethereal place than the Upper Geyser Basin in Yellowstone National Park. There, when the night skies are thick with scudding clouds, ghostly phantoms promenade on the geysers' drifting zephyrs.

Fall can be a downright gorgeous time to take a hike in a national park. The air is crisp, the bugs are gone, the crowds have vanished, and the landscape is gorgeous. Just don't forget that the bears are trying to put on some extra calories to get through the winter. And a hungry bear can be an ornery bear.

As expected, National Park Service officials Thursday approved a winter-use plan for Yellowstone and Grand Teton national parks that reduces snowmobile numbers in Yellowstone from past years. The intent is that this plan remain in effect for two winters while Park Service teams develop yet another environmental impact statement on winter recreation in Yellowstone.