Not for a couple of weeks, but if its suffering the same as Borovets then it won't be in great shape. End of April is one month beyond the end of the main season and whilst we did ski on 8th May last year in Vitosha, there's a lot of rock hopping. If there is snow they tend to keep the lifts open a bit later but there is a real risk that they will close the lifts and you'll have a fun week in a building site.