This way, the rock would be less likely to fall when the sash was loosened by wind and weather.
(the rock; would be; less likely to fall) (the rock; to fall; T:when the sash was loosened by wind and weather) (the sash; was loosened; by wind and weather)
the rock the rock the sash
would be to fall was loosened
less likely to fall
T:when the sash was loosened by wind and weather
by wind and weather