A plan to move the boulder at Challenge has been approved,and the date has been set for Wednesday,November 20th. One concern we have is movement of a large rock like this will stir up a lot of silt,and potentially blow out large sections of cave,which will gradually move downstream. This sudden loss of viz could endanger teams in the water,so it was decided closure would be necessary. A Wednesday was chosen due to this typically is a low visitation day. Thank you for your understanding,and best wishes to the team volunteering to undertake this task.