Arizona's big loop

Just past Heber, State 377 darts northeast into Navajo country, and an odd thing happens: Even though we're still climbing, tall trees thin out and shorter junipers and sage begin to take over.

At Holbrook we turn southeast on U.S. 180 into an even more open landscape carved into buttes and mesas. It's a Southwest scene straight out of a John Ford movie, without a forest-worthy tree in sight. Well, none from later than the Triassic era, anyway. At Petrified Forest National Park (technically a semiarid grassland), we hike among the mineralized remnants of a forest that shaded the earliest dinosaurs 220 million years ago.

The park road leads north over Interstate 40 to Chinde Point, and here, as the shadows lengthen, we look out over a brilliant, rainbow-hued landscape that stretches north to the horizon. This is the Painted Desert, another semiarid grassland considered by some a southeastern extension of the Great Basin Desert. The Great Basin defies the perception of deserts as hot, with temperatures that plunge far below zero in winter. In truth, a desert is simply a place where the annual precipitation is significantly exceeded by the potential for evaporation. The Great Basin Desert is dry because the Sierra Nevada steals most of the Pacific moisture it would otherwise receive.

As the sun sets, we drive 60 miles west on Interstate 40 to Winslow and La Posada Hotel, a gracefully restored masterpiece by the great Southwest architect Mary Colter, who also designed Hermits Rest and several other landmark buildings at the Grand Canyon. The next morning in the hotel's restaurant, we demolish the best breakfast we have ever experienced ― a smoky dish of cornmeal, eggs, spinach, and chipotle chile. Then, with the cruise control set, we blast west across 180 miles of northern Arizona to the junction of U.S. 93, just shy of the California border, and turn south.