I thought it was a ban and had routed around it into the next pass to the east.
Looked closer today since it is now a 'warning' and I think you can head that way.
There's as parallel road on the north side of SS13 that looks useful and bypasses banned/warned section
The warning of SS13 close to CP2 is new, no? Was planning on taking the 111 then ride south on the SS13 and onto the SS54.