 An unusually warm winter , with warm days and cold nights , was also a factor . Water in the mountain 's fissures froze and thawed repeatedly , further weakening the mountain 's supports . Heavy snowfall in the region in March was followed by a warm April , causing the mountain snows to melt into the fissures . GSC geologists concluded that the weather conditions that night likely triggered the slide . The crew of the freight train that arrived at Frank shortly before the disaster said it was the coldest night of the winter , with overnight temperatures falling below − 18 ° C ( 0 ° F ) . Geologists speculated that the cold snap and rapid freezing resulted in expansion of the fissures , causing the limestone to break off and tumble down the mountain . 
 An unusually warm winter , with warm days and cold nights , was also a factor . Water in the mountain <a href='null_genetive' title='1'><mark>'s</mark></a>fissures froze and thawed repeatedly , further weakening the mountain <a href='null_genetive' title='2'><mark>'s</mark></a>supports . Heavy snowfall in the region in March was followed by a warm April , causing the mountain <a href='uninflect' title='3'><mark>snows</mark></a> to melt into the fissures . GSC geologists concluded that the weather conditions that night likely<a href='been_done' title='4'><mark></mark></a> triggered the slide . The crew of the freight train <a href='null_relcl' title='5'><mark>that</mark></a>arrived at Frank shortly before the disaster said it was the coldest night of the winter , with overnight temperatures falling below − 18 ° C ( 0 ° F ) . Geologists speculated that the cold snap and rapid freezing resulted in expansion of the fissures , causing the limestone to break off and tumble down the mountain . 
An unusually warm winter , witt warm days and cold nites , was also a factor . Water in da mountain  fissures froze and thawed repeatedly , further weakening the mountain  supports . Heavy snowfall in the region in March was followed by a warm April , causing tdamountain snow to melt into the fissures . GSC geologists concluded dat the weather conditions that nite likely done triggered thdalide . The crew of thedaeight train arrived at Frank shortly b4 the disaster said it was the dadest nniteof the winter , with overnight temperatures fallin below − 18 ° C ( 0 ° F ) . Geologists speculated that the cda snap and rapid freezin resulted in expansion of the fissures , causing the limestone to break off and tumble down the modaain .