As a result of a breakdown in communications with the band's record label, and a divergence in creative approaches to the music, Palumbo left the band in 1977 to pursue a solo career. The remaining band members, with new vocalist Gary Lee Chappell, Philadelphia guitarist Barry Siegfried and Pittsburgh keyboardist Vince DePaul, released "Safety in Numbers" in 1978. "Safety in Numbers" reached 126 on the "Billboard" chart, their highest charting album. Promoting "Safety in Numbers", Crack the Sky opened for Heart's 1978 Dog and Butterfly tour. Later that year, the band released an album of live concert performances, "Live Sky".