Regarding the loss of the 19 firefighters in Prescott, Arizona, there are a lot of questions to answer once we deal with the shock and grief of the friends and loved ones. There will be an inquiry, technical details will come out, and undoubtedly we'll find out that mistakes were made, and we'll try to ensure that it never happens again.
As far as broad questions go, whether we should risk lives to fight forest fires to save empty homes, the issue of tradeoffs will be examined. We may still be too aggressive when dealing with forest fires, and I have no doubt it happened in this case. The issue of the wildland-urban interface is something we've been struggling with as a society. Whether we continue to allow residential dwellings to be built in difficult terrain nestled in trees is one concern. Another is what is the homeowner(s)' responsibility in terms of risk abatement, and what resources should be deployed to protect these homes. How binding should evacuation orders be?
Also re-assessed will be how wise it is to stamp out every forest fire, as Smokey Bear as advocated for decades. This practice leads to the interruption of what some experts believe is a natural cycle, with regular naturally-occurring fires clearing out forests, thinning out the underbrush and reducing the amount of fuel on the surface. When we do get fires now, instead of having mature forests with lots of space between trees and a manageable amount of ground fuels, we have forests choked with scrawny trees and decades of leaves, mulch and needles on the ground, and the fires burn at higher intensities. Maybe we should let fires burn more often, and just monitor them, and only intervene in specific instances. This wouldn't be popular with the forestry sector however. Every cut block lost is a loss of profit for the companies and jobs for loggers.
In the narrower sense, when we do decide to fight a fire, we have to have personnel on the ground attacking it. There is only so much that can be done from the air. Much like the military have told us, you need 'boots on the ground'. And trucks and pumps and bulldozers. Without ground work, the only way to extinguish a forest fire is to wait for a wet winter, and even then sometimes a fire will flare up again in the spring.
As far as what happened in this specific instance, I hate to second-guess in light of the tragedy, but we'll find out that several mistakes were made by the firefighters themselves and their managers. These firefighters were an elite, advance team, they were put in a precarious position and given an aggressive mission probably, and some conservative decisions should have been made at some point to get/keep them out of harm's way.
There are several ways to ensure firefighter safety in a wildland setting. There are acronyms that crews and bosses use to remind themselves to always be aware. There is the 30-30-30 rule (in Canada), which states that you have to be extra careful when the temperature rises above 30 degrees, the relative humidity drops below 30%, and the wind gusts above 30 km/hr, because conditions can change very rapidly and the fire will burn with extra intensity. Updated, effective weather forecasting is crucial for crews. The use of lookouts, trained crew members who do nothing but keep an eye on the fire and report back to crew bosses when conditions change, is mandatory. So are regular crew briefings, during which any issues are discussed, everyone is made aware of the plan of attack, and hazards to be aware of are highlighted. Effective communications also mean having radios for everyone and using them properly to keep track of everyone. Crews always need to have two ways out, two paths they can follow to escape, at minimum, and a safe zone they can reach quickly, where they can take refuge if the fire changes and they need to back away. The use of the aluminium shelters is an absolute last resort, they should only be deployed in the rarest of cases, and when they are they are even more rarely effective.
Unfortunately, these principles were developed at great cost, when other crews were lost in the past, and are sometimes forgotten and may need to be reinforced. We'll learn, and most probably re-learn some lessons due to this incident, and hopefully this kind of tragic, preventable loss will never occur again.