update (15 May 2012): I just got the info from Namibia Wildlife Resorts (NWR) that the hiking route through the Fish River Canyon has re-opened as anticipated! Great news! [via facebook]
Due to rising water levels in the Fish River Canyon the Namibian Ministry of Environment and Tourism (MET) has decided not to open the popular hiking route through the canyon on 01 May 2012 as is usually the case. The new opening date is anticipated to be the 15 May 2012 depending on the level of water of the Fish River.
The canyon is currently considered unsafe for hikers and therefore closed to any visitors.
Last year (2011) the Fish River Canyon was also closed due to the local rains in the south of Namibia and releases from nearby Hardap and Naute dams.