Fire fighting is indeed an extremely hazardous vocation, especially in the mountains.
The flying is all at low altitude in nasty turbulence (often caused by the fire itself) in poor visibility in smoke. Those factors combined with picking up water over glassy water (no depth perception) & operating in constricted areas in mountainous terrain makes it very challenging requiring outstanding manual piloting skills. Furthermore, rapidly dropping tons of water dramatically upsets the aircraft's flying characteristics that must be immediately corrected.
The Canadair machine is purpose built for this role & it therefore very manoeuverable. The most amazing aircraft to watch are the large ones that have been retired from their normal role & modified for the job - Martin Mars, P3s, Hercules, DC6s, DC10s, B747s, etc. They are not known for their agility & require a amazing skills to safely do their job. Locally here in BC, ConAir in Abbotsford has been modifying & flying these type of machines for decades. I have a couple of ex-military friends who fly for them as they didn't want to do the often boring airline type of job. I really admire these crews.
All you wanted to know about these machines:http://www.conair.ca/https://en.wikipedia.org/wiki/Aerial_firefighting