3.5 mm depression features associated with H-alpha 'disparitions brusques'

The characteristics of 3.5-mm depression features associated with two 'disparation brusques' observed in H-alpha are discussed. The millimeter depressions still exist, although reduced in strength, after the disappearance of the H-alpha filament. The two depressions correspond to temperatures of 600 and 450 K before and to 200 and 250 K after the disappearance of the H-alpha filament.