SLOPES In Montana , the adjoining resorts Big Sky , ( 800 ) 548-4486 , www.bigskyresort.com , and Moonlight Basin , ( 877 ) 822-0430 , www.moonlightbasin.com , have had a relationship that could only be described as frosty since Moonlight opened for the 2003-4 season , when Moonlight broke off as a separate resort instead of continuing as a ski-in , ski-out property development company servicing Big Sky 's terrain as it had since 1994 .