I know that GE does a lot of outdoor testing; shutdown overnight, testers intentionally exposed them to freezing rain up the tailpipe. When restarted they have no N1 rotation for a minute or so until the ice melts and is exhausted.
I think they place a time limit on locked N1, shutdown temporarily then restart until N1 turns OK. This is probably because the LPC (on the fan shaft) pumps air for seal pressurization.