A friend pointed me to an article recently that showed a slide show of "emergency contact" apps for smartphones. One was very well thought out: an app that stored emergency contact information, allergies, and other pertinent things for first responders on the user's phone. The other eight were all variations on a single theme: using the phone's data connection to send location and other information to a personal emergency contact. That model is broken.
Turn off your data.
The first thing I want smartphone users to do in a disaster area is to turn mobile data connections completely off. Why? Because some of the cellular infrastructure in the affected area is likely to have been taken out by the disaster, putting bandwith at a premium, and nearly everyone is going to be trying to communicate at once. The combination of damage to infrastructure and sudden rise in usage can cause more towers to crash and need to be restarted, or to lock up and stop taking new connections.
An LTE data connection with the -Advanced protocol extensions (what most 4G consumers have) can do about 1Gbps (1,000kbps) down and .5Gbps(500kbps) up. A voice connection at high quality is somewhere around 12kbps each way and shrinks if there's less sound to transmit (i.e. only one party talks at a time). An SMS message is 1120 bits, but there's some header info so I'll guess around 1200 bits per message (less if one doesn't use all 140 characters). Note that SMS is unreliable -- that is, your phone has no way of knowing for sure if the message was received intact or when -- so it shouldn't be used for high-priority communications.
I'm making some assumptions[^1] about usage here, but if everyone turned their data connections off -- instead using voice for high-priority comms and SMS for low-priority comms -- whatever remained of the cellular network could support 12x-15x as many users before hitting its saturation point.
"Emergency apps" are not life-saving.
Using data connections in a disaster area to let your friends know you are okay is incredibly irresponsible. Using it to communicate that you are NOT okay is ineffective.
If you are silly enough to make the app talk to a personal contact in the disaster area (I suspect most people use partners, neighbors, etc.), it is up to chance whether they have a good enough connection to ever get the info in the first place, and then up to chance again whether they are in a position to act on it.
There is no easy way for your loved one to get that information to someone in a position to help you, and even if they somehow managed it, there's no way for emergency personnel to know which frantic calls from moms and Aunt Mays and such are reliable tips, and which are noise.
There is no easy way for your loved one to communicate the location you just sent them to emergency personnel. It usually comes down to rough description, which then fails miserably.
Picture this, best case scenario for your "emergency app" sending your mom your location and a "help me" message after a disaster. You luck out and are able to get your message out over a cell tower overloaded due to so many other towers going down. In the process, you prevent 15 other people from calling out for help. Mom is outside the disaster area, so she does get the message intact. She calls your local police and gets the desk Sgt's voice mail because the calls are coming in too fast to take. She tries the state police, but they aren't sure who's near your location and put her on hold while they figure out where to route the call. She gets disconnected and tries again. This time someone who knows how to route her call to the 911 call center nearest you answers, but she's put on hold again. She's informed that welfare checks are on hold due to disaster, and that one must wait at least 24 hours (48 in some jurisdictions) to report an adult missing.
Your mom is persistent, and gets forwarded to some rookie whose job it is to take reports that no one is likely to act on. The rookie hears that your mom got a specific distress call with location, and talks your (now frantic) mother down enough to get the coordinates you sent. The rookie gets a patrol car to go by that location, but the coffee shop the GPS coords pointed to was completely empty. The patrolmen look around a bit but never find you, because you're pinned under a fallen beam in the art studio on the alley behind the coffee shop and the GPS was a few meters off. They assume that your mom was crazy and move on to disasters they can fix.
That's the best case scenario.
Call 911, then whistle.
Contrast this with a voice call to 911:
The first thing that emergency communications people work on after a disaster hits is the 911 system. 911 call centers in most areas have redundant power systems, and in any case they are second only to hospitals for power restoration. 911 call centers are first priority for telecommunications restoration, and when the radio systems they use to contact police, fire, ambulance, and rescue personnel on the ground fail, amateur radio operators step in with new infrastructure to replace the old -- usually in a couple hours or less. This is the most likely phone-based system to be working.
911 call centers in population-dense areas have equipment that feeds them the GPS location reported by your mobile phone when you call, and seasoned operators usually have a feel for how accurate those coordinates are or aren't in each area under their responsibility.
911 call centers know which units are operating where, and can route your information to someone who is actually close enough to help you.
Even if you can't make a sound, and just call and listen, you are letting 911 know you need help.
Because 911 is getting a call from a victim, not a missing person report from a third party, they can act immediately.
You're better off making a voice call and having a whistle on your person. An extremely high-end, best-in-class, screaming-loud whistle is about $4-6, and less nice ones can be found for about $1.75. You can only yell for a few minutes (a bratty child maxes out around ten minutes, a well-trained vocalist might make thirty with short breaks) before your voice gives out. An emergency whistle carries further than your voice, and won't give out as long as you can breathe. Rescue personnel AND search dogs listen for a whistle and can follow it more easily than a voice.
Rescue workers, depending on their training, will either sing while they search (common among wilderness S&R teams I worked with in the south), or yell something like "Fire Department -- call out!" (common among police and fire, as well as S&R teams I met on the west coast and my team down south when in more urban areas). Rescue dogs usually wear bells so you can hear when one is near you. If you don't have a whistle, try to yell, or bang on something like a pipe that will make the sound travel. If you have to resort to banging, use a rhythm (S-O-S is "... --- ..." where a '.' is a short bang and a '-' is a long one) so we can easily tell that you are a person in need of help, not stuff falling down or water dripping.
Want to go the extra mile?
If that doesn't sound "good enough" for you, consider this: a ham (amateur) radio will keep working as long as it has power, even if all the cell towers and phone lines are down, even if power is out and you're relying on your battery. Study materials are free, but testing for your ham license can cost up to $25, though if you are broke enough to make that prohibitive, contact me and I'll find a way to let you sit the test for free. A low-end ham radio costs $30-$40 shipped, while a fancy one that can transmit your GPS coordinates automatically runs just under $400.
Let's assume you go for the low-end radio. A number of amateur radio operators spend their free time training to monitor (and if needed replace) radio repeaters (systems that listen for and retransmit your signal, allowing it to go further) in disaster areas. Search and rescue workers carry these radios. The cheap one I bought can also be hacked to transmit on police, fire, and ambulance channels (which is legal in a life-or-death emergency, but a crime any other time). Calling out on a ham radio means instant access to emergency services, even if the power grid and every cell tower and phone line is down...for less than $100 in testing and equipment.
By the way, even if you get the low-end radio (no GPS), ham radio teams practice to locate you by triangulating your radio signal! As long as you transmit regularly, they can compare the strength of your signal from multiple receiver points and get your location. (See! High school geometry is important after all!) Additionally, the SOS pattern I just taught you above can be keyed into your radio with a button so you can call for help while unable to speak. It helps to also practice doing your call sign in morse code (every licensed ham operator gets a unique call sign of 3-6 characters) so the person receiving knows who you are.
When (not) to contact emergency services.
In an immediate life-or-death situation, do your best to contact emergency services as described above. In any other situation, do a best assessment. Given your current condition and supplies, how long can you be reasonably comfortable (i.e. warm or cool enough to maintain a safe body temperature, no grievous injury that's going to get worse or threaten life or limb, enough food and clean water, no immediate threat of physical violence)? How long can you survive (i.e. no severe hypo- or hyper-thermia, no death by starvation, dehydration, or running out of life-sustaining medical support, no physical violence you can't cope with)?
If the answer is "I/we can probably survive until normal infrastructure is mostly restored.", hunker down and make do until and unless that assessment changes, so that emergency services can focus on the people who need them. If you do need to call, be ready to give emergency services the information they need to prioritize more severe cases over those that can wait an hour or a day.
Better yet, if you are in reasonably good shape, check on those near you and assess the conditions of the group, communicating through one channel to emergency services if needed, and helping in any other way you can. If you can check on three neighboring homes and find a need to call in, you can call in with information about the problem needing response as well as a head count and general conditions for others across four residences, reducing triage overhead for the emergency responders. If you can solve the problems at hand, you've taken four homes off the list of things that need responding to, freeing up personnel and other resources for those in greater need.
Contacting loved ones.
When a disaster strikes, loved ones want to know one another are okay and be together. It's a natural part of human support systems. Additionally, there may be real logistical reasons to be together, for example so that a parent may care for their child.
However, if you are outside a disaster area and want to help your loved one survive, the absolute best thing you can do is to sit on your hands and don't call them. As I explained previously, it is likely that the communications infrastructure in the disaster area is overloaded, potentially near the point of collapse. The best way to protect it is to reduce traffic.
If you are in a disaster area, text or use a land line (or wired internet connection, preferably with a low-bandwith protocol like email, instant message, or IRC rather than video or voice chat) to contact one trusted person outside the disaster area. Give this person a list of secondary contacts outside the disaster area they should call to let them know you are okay, as well as information on how to find you for anyone in the disaster area (such as your child) who may need to do so. Train your friends and loved ones to check with one of those contacts to find out how you are instead of calling you; this way the strain on disaster area communications infrastructure is reduced.
For example, when there was a large-ish explosion in Indianapolis (nowhere near me), no one in my family or my hometown called to find out whether I was okay. I texted my mom to tell her that my son and I were fine, and got a text back from her confirming that she got the message. My aunts, brother, family friends, and so on checked in with my parents rather than trying to contact me. I also contacted my boyfriend outside the city, and asked him to notify a few people for me.
Some friends of mine from the martial arts community and tech communities get it. They called mutual friends, boyfriend, etc or checked my status online (which I did set in two places) to be sure I was okay. Some didn't, and called me directly. Despite only one cell tower being directly impacted by the blast (due to power loss in the neighborhood where a house blew up), the cell network in Indianapolis was overloaded that day. The two towers nearest my home went down a couple of times -- probably crashed and had to restart due to the load. My friends who called me contributed to that. Luckily, my area was not directly impacted so it is unlikely the towers being overloaded prevented anyone from getting help.
It's also worth noting that if I am directly impacted by a disaster, the last thing I need to be doing is juggling 40 phone calls. Calling me isn't helping. There are plenty of people you can call if you need to know how I am. Let me deal with the problems in front of me.
Finally, were my son and I separated in a disaster, he has the following protocol by which to find me:
Get somewhere you are not in immediate danger.
Try to call me directly.
If that fails, call my boyfriend and meet up with him so he can keep you safe until I can be reached.
If that fails, call my search and rescue group to see if they can find me or if someone can bring you to our base of operations where you can help out until I come in.
If that fails, call Grandma and Grandpa to tell them exactly where you are and find out if I left a message for you about how to get together with me or another trusted adult.
If that fails, find any ham operator, police officer, paramedic, fireman, or rescue worker with access to a radio. Give them my name, my ham callsign, and the name of my search and rescue group so that they can track me down.
Of course, if he happens to be sitting by one of my or my boyfriends' extra radios, he knows that "lost 11-year-old in a disaster area" is enough of an emergency to use it unlicensed to track me down. He also knows that my first priority is ensuring his safety, so all other operations are on hold until I've tracked him down.
In case you cannot communicate.
Write down your full name, your blood type, any medications you are on, any medical conditions you have (including allergies!), and contact information for 2-5 people in different geographic locations in order of your preference for them dealing with you being unconscious, and keep it in your wallet at all times. Duplicating this info to your phone is good, too, but only if there's a way for emergency responders to access it without you being able to unlock your phone. If you use your phone, have a paper backup in your wallet in case your phone is damaged or the battery dies.
If your medical situation is complicated, or would require very fast response (e.g. if you are diabetic, have a heart condition, or have a life-threatening allergy) consider a Medic Alert bracelet because responders will see that first, giving them instant info (e.g. "HIV positive" or "diabetic") plus the ability to look up more detailed info in the corresponding computer systems (assuming they are available).
Communication infrastructure is under high strain in a disaster area. The higher the load gets, the more likely it becomes that more failures will happen, preventing people from getting needed help. Turn off your phone's data connection in order to give people the best chance of being able to call out when needed.
Use voice for life-critical communications, and SMS for anything not life-critical. Remember that SMS is nearly free in terms of the load it puts on cell towers.
911 call centers are infinitely better than a far-away loved one (or someone stuck in the same situation you are) at getting emergency services personnel routed to you.
An emergency whistle is an inexpensive item that can save your life.
A ham radio is the most reliable form of long distance (out of whistle range) communication in a disaster area.
Contacting someone outside the disaster area to let them know you are okay can give your loved ones peace of mind.
Contacting someone inside the disaster area to check on them directly, instead of calling whomever is outside the disaster area that they would contact, should be considered socially unacceptable due to burdens on the communications system and the person in the disaster area.
The most reliable way to reunite with loved ones is to have a designated contact person outside the disaster area who can coordinate meeting up.
Sometimes the smartest thing to do is to wait a bit and let things calm down.
[^1]: Given sporadic usage at about 20Mb/day -- which is pretty normal for someone who has background sync on and uses maybe the twitter app or GPS guidance, but no video or other bandwidth-heavy things -- not counting additional traffic from "emergency apps", every data user who turns off their data would make room for about 30 2-5 minute voice calls and 5,500 SMS messages per day.