All those events you mentioned had one thing in common, lack of vegetative uptake and ground cover to slow runoff. Hydrological modeling can now use various stages of forest land growth and antecedent conditions to predict river stages. At URI we were at the forefront of current GIS flood mapping developing tools and equations to make Hydrological modeling more accurate. Did you know that as late as 1993 modeling did not take into account frozen ground? I was involved with Dr Art Gold in developing new technology to add frozen ground into Hydrological equations.