All it takes is a couple of lowly hams with mobile radios to cover a huge area...in practice during recent emergencies here in rural norcal, ham radio was really useful, for updates on general news, determining the status of communities around the county, passing messages, and fire spotting. Some of those guys driving up to hilltops were putting their lives at risk so the rest of us could benefit.
We practice every week, so everybody who is an active ham knows the local frequency and they know that there will be updates every hour on the hour.
On top of that, the local WIN System repeater (Western Intertie Network, check their website) was up on backup power, meaning I could have used my walkie-talkie-type radio to get help from distant places like Ireland or Hawaii, if it would have been useful. To say nothing of the amateur radio satellites and HF operation.
One of our local nets during the emergency was a tech-talk net, with about 41 check-ins, all but one on emergency power, when the usual is about 7-12 people. The time was used to discuss lessons learned and one ham is an expert with generators and warned everybody: Change the oil every few days if you are running 24/7. A lot of people were surprised to hear that. And many of them only had one generator to burn through.
To give another example of the usefulness: Imagine, your power goes out, and a day passes without anything exciting happening, so you take a nap, forgetting that the reason the power is out is actually high fire risk.
In a few minutes you wake to a phone call. Your ham radio friend tells you he just heard on the radio a wildfire started a few miles north of your community. This is not on Facebook, it's not anything your neighbors know about.
So you have no idea what to do but fortunately they keep calling with updates from the radio. Eventually they call and give you the all clear and let you know your evacuation warning was lifted, so you don't have to take whatever you can and leave town with your family, spending money and using every last nerve you have just to figure out the next 24 hours.
This is just one specific example that happened here. Everybody else would have warning via text if they were lucky (had battery, tower connection, and proper system configuration), and final warning via a sheriff's vehicle siren if that didn't get through to them. In this case the person receiving calls never got a single text message.
This highlights a critical element of emergency notifications and response: you have to have a plan for how to deal with warnings and alerts. If you don't, then the alert is worthless.
It may even be worse than useless by throwing an otherwise orderly and predictable population into a panic.
How you respond to an emergency, in general, is to reduce risks and consequences. This may mean moving out of the area, but more generally, it means moving out of immediate harm's way. In the event of an earthquake, that can simply be to more out of range of falling debris, or into a solidly-constructed building. For a tsunami, gaining elevation on a secure base (terrain, a very solidly-constructed building). And, of course, responding to changing circumstances and conditions as appropriate.
For widespread disasters -- hurricane and wildfires -- exiting the region or moving to a location that's unlikely to be overwhelmed by the forces at play, is helpful.
For high wind, rain, cold, heat, etc., the challenges often play out over a longer period of time.
Disaster response as with security risks should revolve around threat models. What are the foreseeable threats, what are their specific mechanisms of action (e.g., fire, smoke, heat, wind, flood, ground movement), what's the effected range, and how can the hazards be reduced, mitigated, or countered?
Then there are the long-term survival needs: water, food, shelter, transport, injury and health treatment. Ultimately, rebuilding or relocation.
In one of the biggest disasters of all time, the Bianqao hydroelectric dam collapse following the intersection of a tropical storm and a cold-weather front, about 30,000 deaths were the immediate result of flooding. Another 150,000 or more resulted over the ensuing days and weeks from disease and starvation given both the disruption to ordinary life and the inability to move rescue, recovery, and relief personnel and supplies into the affected area.
None of which has an immediate relation to the ham vs. mesh-network radio debate, but calls into consideration that each are only a small part of an overall disaster response plan.
We practice every week, so everybody who is an active ham knows the local frequency and they know that there will be updates every hour on the hour.
On top of that, the local WIN System repeater (Western Intertie Network, check their website) was up on backup power, meaning I could have used my walkie-talkie-type radio to get help from distant places like Ireland or Hawaii, if it would have been useful. To say nothing of the amateur radio satellites and HF operation.
One of our local nets during the emergency was a tech-talk net, with about 41 check-ins, all but one on emergency power, when the usual is about 7-12 people. The time was used to discuss lessons learned and one ham is an expert with generators and warned everybody: Change the oil every few days if you are running 24/7. A lot of people were surprised to hear that. And many of them only had one generator to burn through.
To give another example of the usefulness: Imagine, your power goes out, and a day passes without anything exciting happening, so you take a nap, forgetting that the reason the power is out is actually high fire risk.
In a few minutes you wake to a phone call. Your ham radio friend tells you he just heard on the radio a wildfire started a few miles north of your community. This is not on Facebook, it's not anything your neighbors know about.
So you have no idea what to do but fortunately they keep calling with updates from the radio. Eventually they call and give you the all clear and let you know your evacuation warning was lifted, so you don't have to take whatever you can and leave town with your family, spending money and using every last nerve you have just to figure out the next 24 hours.
This is just one specific example that happened here. Everybody else would have warning via text if they were lucky (had battery, tower connection, and proper system configuration), and final warning via a sheriff's vehicle siren if that didn't get through to them. In this case the person receiving calls never got a single text message.