these fire fighting operations probably have the highest fatality and accident rates of any kind of flying, other than war time. They also tend to fly some of the oldest. creakiest and decrepit types of aircraft subjected to incredibly high g-forces and stresses. you have to drop the water really low, otherwise you just create a cloud of useless steam at 300ft - some planes skim the surface of a lake and load up water, where a unseen log or canoe spells disaster.
Makes me wonder everytime I hear of one of these crashes , if it wouldnt be better to just let the damn fire burn ( of course, if MY home was in the 'line of fire') then I would probably have a different suggestion!)
^photo from wiki