Foreshadowing occurs from the very onset of Suzanne Collins' Mockingjay in the first chapter as Katniss revisits the bombed-out District 12. 

In her house in the Victor's Village, Katniss Everdeen finds a "dab of white [that] peeks out of a vase of dried flowers" (14).  On closer inspection, Katniss discovers that it is a "fresh white rose.  Perfect. Down to the last thorn and silken petal" (14). 

Katniss reels from the realization that the rose is from President Snow, "a promise of revenge" (15).  Collins uses this moment in the novel, Katniss' horrified discovery, to foreshadow the looming conflict to come between President Snow and Katniss Everdeen.  The snow white flower is as much of a reminder for Katniss as it is for the reader, sending the message that there is still much to come from both of the characters.  Ultimately, Katniss and President Snow will have to deal with their "unfinished business" (15).