Use the Winter Effects Accent Kit. Mix the Snow Flakes with the Snow Base, included in the kit. This will create the perfect mixture for snowdrifts.
A waterfall can be made with the Waterfall Diorama Kit or the Ripplin' Water Accents Kit. Go to the following link to view a demonstration. http://woodlandscenics.woodlandscenics.com/FlashVideos/MakeWaterFall.html
The Building & Structure Kit (SP4130) wood can only be bent if it is soaked in hot tap water first. Be sure it is completely saturated and be very careful with bending or it will break.