Anza-Borrego's Smoke Tree Canyon twists its way into the barren flanks of the Santa Rosa Mountains.

Stark and barren, yet glorious in their nakedness, Anza-Borrego's skeletal mountain ranges conceal more than they reveal to casual passersby. If you want to know them better, you must leave the security of the automotive cocoon and start walking -- up a canyon or a wash or onto a hardscrabble ridge sweeping upward into the fierce blue sky.

The southern spurs of the Santa Rosa Mountains are as good a place as any to do this. Midday temperatures are rising into the 70s and 80s now -- warm but not too hot for an extended hike of six to ten miles, such as the one up along Smoke Tree Wash profiled here. Wear hiking boots to keep cactus spines at bay, and carry at least a pint of water for each hour of hiking. For parking by the roadside, you'll need an Anza-Borrego permit, $5 daily or $50 annual (for information, call 760-767-4205 or 760-767-5311).

To get to Smoke Tree Wash, drive east from Borrego Springs on Highway S-22 (Palm Canyon Drive and later Borrego-Salton Seaway) and park near mile 34.6, about 0.2 mile west of the signed entrance to Arroyo Salado Campground. On foot, simply follow the wide, sandy bed of Smoke Tree Wash north into the mountains looming above. Flat and easy to travel at first, the wash progressively narrows to what becomes, at 2.3 miles, a fissure overhung by menacing conglomerate cliffs (definitely not a good place to be during an earthquake). Up the canyon another 0.5 mile, look for a major side canyon on the right, heading northeast. Scramble up this side canyon a short distance to discover the Natural Rock Tanks -- large depressions in the bedrock created by the scouring action of flash floods. The tanks hold water for weeks or months after major storms, temporarily meeting the needs of the local bighorn sheep.

You can retrace your steps back to your car, completing a hike of nearly six miles. Or you can extend your exploration by traveling west a short distance on an obscure, disused miner's trail or north a mile or more through various upper tributaries of Smoke Tree Canyon. By climbing upward toward any ridgeline or peaklet in that area, you'll get a fine view of the corrugated Borrego Badlands to the south and the flat, spacious Borrego Valley to the southwest.