Twin Falls is somewhat of a misnomer of a title for this waterfall. Wilson Creek drains from the Ashland Lakes, which occupy a flat(ish) plateau beween Mount Pilchuck and Bald Mountain south of the Mountain Loop Highway. This plateau was formed thanks to a tongue of the Cordilleran Ice Sheet extending across the ridge during the last ice age. Meltwater from the glacier lobe flowed south and scoured out a narrow notch in the valley. As it thundered downhill it carved a deep pothole in the bedrock and after the ice retreated and Wilson Creek took the place of the former river, it filled up the pothole forming tiny Twin Falls Lake, with the lacy veil of 138 foot Twin Falls plunging directly into it.
Because Wilson Creek is essentially fed by two small lakes and some swampland upstream from the falls, it will exhibit significant seasonal fluctuation in volume, ranging from a fairly powerful plunge during the spring to a very delicate plume in the autumn. As such the falls are not really worth visiting after the end of July outside of heavy snow years.
- Twin Falls is the Official name of this waterfall.
- Known Alternate Names: Upper Twin Falls
The naming of Twin Falls and its lake is almost a Chicken-or-Egg scenario. Twin Falls Lake was named for the presence of waterfalls on Wilson Creek plunging both into and out of the lake. The USGS however only distinguishes the falls dropping into the lake as Twin Falls, instead of referring to them collectively as the name would suggest. We find this to be the most logical convention as well, since the linear distance between the two falls is considerable thanks to the presence of the lake. So ultimately Twin Falls is not at all an accurate name for this waterfall itself, but it would essentially be heresy to change it to anything else.
Starting in the town of Granite Falls, drive east along the Mountain Loop Highway for 16 1/4 miles and turn right onto FSR # 4020, signed for Boardman Lake, Ashland Lakes and Pinnacle Lake. Follow road 4020 for 2 3/4 miles then make a sharp right onto FSR # 4021, again signed for Ashland Lakes and Pinnacle Lake. Follow road 4021 for 1.4 miles then bear left at the sign for the Ashland Lakes trailhead and proceed less than 1000 feet further to the parking area. The Ashland Lakes trail beings along an old roadbed and climbs moderately to the Ashland Lakes basin. At all trail junctions stay to the right (the exceptions being trails leading to campsites). After 2.5 miles the trail to Twin Falls Lake will head right, crossing Wilson Creek shortly and becoming steeper and brushier as it descends another mile to Twin Falls Lake and the falls. As of May 2011 the trail between Lower Ashland Lake and Twin Falls Lake was closed due to several collapsed bridges.