Descend into Big Tujunga Canyon, a deep gash in the San Gabriel Mountains.

Angeles National Forest's Fall Creek Trail threads the steep, north wall of Big Tujunga Canyon and offers unique vistas of Big Tujunga's dramatic "Narrows" section below. Big Tujunga Canyon drains much of the western end of the San Gabriel Mountains, and was the site, a century ago, of the shooting of one of the last of California's native grizzly bears.

If you can facilitate transportation with the use of two cars -- or get someone to drop you off at the start and pick you up at the finish -- you can turn the Fall Creek Trail route into a pleasant one-way hike. It doesn't really matter which direction you go, since the start and end points of the one-way route lie on virtually the same elevation contour. Mornings, you may prefer going west to keep the sun out of your eyes; afternoons, going east is probably better. Either way you descend into the bottom of Big Tujunga Canyon with a net elevation loss of about 650 feet, cross the creek, then climb an equal net elevation to get back up the other side.

High-volume flows in Big Tujunga creek in recent months have made crossing the creek difficult -- though now with the onset of summer drought that flow is slackening. At the same time, the days are lengthening and the spring-green vegetation is beginning to dry up. By mid-June this hike will lose much of its beauty and appeal. For the latest on trail and creek-crossing conditions, call Angeles National Forest, 626-574-1613. General information can be obtained by visiting www.fs.fed.us/r5/angeles.

Assuming you hike in the east-to-west direction, you will begin at Hidden Springs Picnic Area, on Angeles Forest Highway just north of a tunnel located about three miles northeast of the intersection of Angeles Forest Highway and Big Tujunga Road. (San Diegans approaching from the south can most easily reach Angeles Forest Highway by taking Angeles Crest Highway north from Interstate 210 at La Cañada.) At the picnic area, and elsewhere in these mountains, don't forget to display the necessary National Forest Adventure Pass on your parked car.

The trail doesn't start at the campground, but rather from the highway shoulder about 300 yards north. It goes up along a small canyon (North Fork Mill Creek) a short distance and then veers left along a brushy hillside. After gaining roughly 800 feet in a mile, the trail levels, contours for another mile, and then begins dropping steadily into Big Tujunga Canyon.

You're almost never completely out of sight or sound of the curling ribbons of asphalt and traffic below, but at least the trail smells of wilderness and wild chaparral. The sun-warmed slopes positively reek of sweet-smelling ceanothus (wild lilac) blossoms, and pungent yerba santa and sage. While you're on the descent phase, enjoy the view up the V-shaped gash of Big Tujunga's Narrows to the east.

At 3.5 miles, the footpath you're on ends at a junction of dirt roads. The left branch leads 200 yards east to Fall Creek Trail Camp (a former work camp -- tables, stoves, and ornamental plantings gone wild), while the middle branch (our one-way route) descends to the gravelly floor of Big Tujunga Canyon. After fording the wide but shallow creek, continue west on the fire road that crookedly ascends the canyon's steep south wall. On the way up, look across the canyon to see water shooting (or dribbling later in the season) down a moss-covered ledge in Fall Creek. The fire road ends at a turnout on Big Tujunga Canyon Road, 0.7 mile west of Angeles Forest Highway, and so does your one-way hike.