From Book 1: RIDE THE RAINBOW HOME
"Oh!" Meg jumped as lightning crashed overhead. She swerved slightly, but fought her sports car back into her lane. July had come to the high plateau and with it, a typical afternoon thundershower. To Margaret Taylor, who hadn't seen the plateau for years, the storm was anything but typical. Lightning danced along the ridges and shimmered through the valley of the Little Colorado River, sending thunder rumbling in its wake. Giant thunderheads loomed thousands of feet above the red sandstone cliffs, pierced here and there by shafts of yellow light that brought heaven to earth.
From Book 2: AT THE RAINBOW'S END