Vertical basalt walls along the Columbia River Gorge are graced with the greatest concentration of waterfalls in North America, particularly along the Oregon side of the western Gorge. Here are some favorites:

• Multnomah Falls
  Tallest in North America after Yosemite Falls, 620-foot Multnomah is the focal point for a network of trails. There's also fine dining at Multnomah Falls Lodge. Access is from Interstate 84 or the Columbia River Scenic Highway east of Bridal Veil.

• Horsetail Falls
  This 176-foot waterfall plunges into a pool right beside the Columbia River Scenic Highway; it's also visible through a corridor cut through vegetation to Interstate 84, 2.5 miles east of Multnomah Falls.

• Triple Falls
  Not a series of falls, but rather three parallel chutes ranging from 100 to 135 feet tall. The viewpoint is located on Oneonta Trail #424, 1.7 miles from the trailhead, which is just under a mile from Horsetail Falls Trailhead #438. Both are located on the Columbia River Scenic Highway east of Multnomah Falls.

• Ponytail Falls
  Before making the plunge over Horsetail Falls, Horsetail Creek is shot through a narrow crack and exploded out into a pool in front of a deep recess, which allows a trail to pass behind the falls.

• Punchbowl Falls
  Frequently pictured on Columbia Gorge photographic calendars, Punchbowl is located on Eagle Creek Trail #440 2.1 miles south of the trailhead. Caution: this is a precipitous trail not suitable for young children or dogs. There's an access trail leading off the main trail to the base of Punchbowl Falls, which plunges 10 to 15 feet into a basin. You reach Eagle Creek by taking Exit 41 eastbound, or Exit 40 westbound and loop back east on the freeway to Exit 41. From Eagle Creek Fish Hatchery, follow the access road south to the trailhead parking area.

• Metlako Falls
  Also located on Eagle Creek Trail, Metlako plunges about 125 feet; the waterfall is named after a Native American salmon goddess.

• Tunnel Falls
  Located about a dozen miles up the Eagle Creek Trail, this waterfall is named for the trail's passage through a rock tunnel blasted behind the waterfall, midway up a vertical basalt wall. It's breathtaking but be careful to stay on the trail. Just beyond Tunnel Falls the trail rounds a corner at the head of another waterfall, located on a different fork of Eagle Creek.

• Wah-kee-na Falls
  This 242-foot tiered waterfall (the Yakama name translates as "most beautiful") is located half a mile west of Multnomah Falls on the Historic Columbia River Scenic Highway. A picnic area is nearby.

• Elowah Falls/McCord Creek Falls
  Separate waterfalls located on McCord Creek, a short hike east of the Nesmith Mountain trailhead. The upper falls features a natural amphitheater. Take Dodson-Warrendale Exit 35 from Interstate 84 east of Multnomah Falls; the trailhead is located just before the eastbound freeway on-ramp at John B. Yeon Park.

• Latourell Falls
  A 249-foot plunge falls in Guy W. Talbot State Park, 3.4 miles west of Exit 28 off Interstate 84.

• Bridal Veil Falls
  A tiered waterfall with two drops, the upper between 60 and 100 feet tall, the lower from 40 to 60 feet in height. Parking is a mile west of Exit 28 off Interstate 84. There's a path to the lower falls. The nearby community of Bridal Veil maintains its post office, a popular place for nuptial announcements.

• Sheppard's Dell
  Tiered waterfall two miles west of Interstate 84's Exit 28 on the Historic Columbia River Scenic Highway. Short, paved trail leads to the top of the falls.

• Dog Creek Falls
  Located off Washington Highway 14 east of Wind Mountain.

• Hardy Falls
  A horsetail-type waterfall, about 100 feet high, located in Beacon Rock State Park west of Stevenson. Turn off Washington Highway 14 to the park access road, drive to the picnic area and trailhead to Hamilton Mountain. Follow the trail 1.25 miles to spur trails; upper path to right leads to waterfall viewpoint.

Why are there fewer waterfalls on the Washington side of the Columbia River? It's drier, for one thing, since the Washington side faces south and receives more sunlight. More importantly, though, is the underlying geology. The Washington side is an unstable "layer cake" of dense basalt on top of softer, unconsolidated rocks, and the whole assembly tilts to the south as it follows the buried slope of an extinct volcano. Earthquakes and ground saturation have given rise to numerous landslides, which have reduced the slope along the Washington side of the western Gorge. With fewer vertical drops, there are fewer waterfalls.

Information courtesy of the Volunteers in the Gorge