I live in San Diego county and had first-hand experience in the 2003 and 2007 fire. The combined total area burned was 500,000 acres. Huge. In both fires, I could see the flames from the fires. Our exit route? Not towards the flames and smoke. Duh....
With the 2007 fire we got a 6 am robo call ("reverse 911") that two fires were converging and in 30 minutes our area would be overcome. That helped a lot. They didn't say go north, or go south, etc. But WE KNEW that there was a life-threatening problem and we knew our exit options. I think that if the sirens in Lahaina would have sounded, many people may not have burned to death. So, immediately we turned on our TV, turned on Ham Radio, looked outside at the smoke and figured out what was going on. Also, we packed out cars ready to evacuate. BTW, in a fire, if you can smell smoke, you are -- by definition - - downwind of the fire. That is a big warning sign.
It is so sad that this fire took the course it did - - excess fuel not remediated over several years of neglect (i.e. grass/brush), too many dwellings with flammable roofs, wooden fences connected directly to house, no defensible space, no FD units quickly on site to put out the re-ignition (at the same location) of the earlier fire, no alarm sounded, no water available to put out the fire, police not effectively helping people to evacuate. Honestly, I can't think of a worst way to have stacked the deck against Lahaina.
Shift to Lahaina - - IMHO that were several hours from when the fire started to go out of control to when the phone lines went down. Why weren't people notified? There were hours from when the fire re-emerged to when they could have sounded the sirens. The second fire appears to have been the same location as the initial fire - - why weren't there FD units held back ... just in case?
In SD county, the thousands of homes that burned tended to have inadequate "defensible space", had wooden fences connecting to the house, had flammable roofs, had too little space between buildings, had too much "fuel" too close to the house (wooden deck, patio furniture and fences, etc)_. IMHO, Lahaina was a disaster waiting to happen. Hopefully when they rebuild they'll address these issues.