Avalanche control systems had triggered avalanche in the adjacent chute but failed to trigger an avalanche in this chute. This was an inbounds at Crystal. Slab avalanche was considered highly unlikely as the slope was directly below the Gazex avalanche control systems. Loose avalanche was expected. However, a small slab avalanche propagated in the chute at the previous day's interface. Suspect the interface was created by the rapid warming event accompanied by rain on Saturday followed by rapid cooling that occurred Saturday night accompanied by high winds and 6 to 8 inches of new snow.