The Oregon Department Of Transportation says it will keep a two-mile section of the Historic Columbia River Highway west of Multnomah Falls closed until at least Wednesday afternoon while crews evaluate whether a small Tuesday morning slide indicates a more serious threat.   The road will remain closed between Multnomah Falls and the Angel’s Rest trailhead.  ODOT geologists and hydrologists inspected the area Tuesday morning and determined that the road should remain closed as a safety precaution.  The heavy rain forecast for the Columbia River Gorge could create further instability in an area prone to slides.  Crews will consider Wednesday whether to reopen the road.