When patching RTCW from 1.3 to 1.3.1 the mp_ice map desappears. id have made some changes and when you patch the game it does not load the map anymore.
A possible solution that works is: open the previous 1.3 patch and extract the mp_pakmaps1.pk3 to the /main folder in RtCW and overwrite the new file. It seems that id brings new problems with the new patches. The patch was released yesterday and adresses these issues: Teleportation and Reviving Players Bugs Fixed Bugs introduced in 1.30 related to reviving players and teleportation, or warping, on certain maps have been fixed. These issues were a byproduct of a fix for reviving players on and around script movers (the giant doors in mp_assault for example).