Kirstin died in a car crash near Lovelock, NV, on May 17, 1990. She was in the car with her fiancee, NBA player Todd Lichti, at the time. Lichti was bringing her home to meet his family in Northern California when Kirstin fell asleep at the wheel, and the car overturned in the median. Lichti was injured and survived, but Kirstin died at the scene. She was only 23 years old.
A newspaper article about the crash can be found here.