You use whatever tools you have, and in this case it was an EC-120: Good Job Guys.
There are plenty of initial attack operations in North America that are hit with light ships; what is being suggested here - they wait for something larger and more effective?
The US Forest Serviec has come to the realization (finally) that if they had an effective, highly mobile, Initial Attack capability; they would stop way more fires in the early stages, than by bringing in heavy iron 24 hours later. The current contracting round is in process, but the likelihood is, you will see a large number of S61's with tanks, seats and hoists/rappel capabilities operating in this role from this year forward. The variety of aircraft in this role includes: 206 series; 407's; 350's; 205's; 212's; 214B and ST, and Lama's - plus others, I'm sure.
I have rented out everything including a piston Hiller with a bucket over the years. In an act of desperation the Hiller was rented to one of our major customers after the Government kept commandeering everything they secured. Eventually the Hiller was all that remained, and I happened to have seen this dinky little fibreglass bucket in the back of the hangar the same day and asked what it was. When the call came later in the day, off she went and stayed gone for weeks!
The other observation here that is very important - fires are put out by people on the ground, working extremely hard. Helicopters and Aircraft dropping water are an important part of that process, but they are not the end by themselves.