Eh Captain think you have the wrong site mate. You see at the top of the page it says Bulgariaski? Not Sierra Nevada! Cant speek fo everyone but I have this feeling that most of us dont care!! (no offence!)
The people on this site are usually very helpful and have quite possibly been on their travels to sierra nevada skiing before........cant be assed explaining
Sierra Nevada mountain range runs along most of west america. Seasons will vary depending on height of resort. I went to Mammoth Mountain in california last april, 21st. Stayed for 2 weeks, boarding was excellent with good dump of snow on the first 2 days then mainly sunny for the rest. MM peak is 11,500 ft which is why it is open so late.