Highway 243 spurs off Highway 26 just south of the Interstate 90 bridge over the Columbia River. 243 follows the Columbia River south to Highway 24 just north of the Highway 24 bridge across the Columbia. The scenic highlight is Sentinel Gap where the river passes through the Saddle Mountain ridge.
1,600-foot cliffs and talus slopes in the gap
The foreground feature of trees along the river is a relatively new development.
The dams on the Columbia River, particular the Canadian dams, prevent the Columbia from the past wild seasonal swings in river flow. The tamed river no longer has huge late spring and early summer floods as the Canadian dams hold water back. The loss of these large flood events has allowed trees to become established along portions of the river bank where previously the floods would have removed them. The river reach at Sentinel Gap has become progressively more wooded over the decades since the dam building era. The trees are a mix of willow, cottonwood and juniper as well as other brush,and this growth has formed a new ecosystem along the river.