One of our greatest vulnerabilities is our reliance on cellular communication.
Cell towers are not difficult to take off-line. They are power intensive. The units on the ground generate a lot of heat. A can of expanding foam insulation or a blizzard of disposable, plastic grocery bags will interrupt the flow of cooling air into the cabinets. Silicon does not like heat.
So, what is a fella supposed to do?
This is where prior planning prevents piss-poor performance.
Pre-arranged rally points is one example. In my case, home is always the ultimate goal.
However, there might be circumstances where it is not safe to get there. Hostiles might control areas or bridges between my (or a family member's) current location and home. Knowing where to go instead takes a lot of stress off of everybody's mind.
Low tech, like a foot off the ground tech, involves the use of common, wooden clothes pin, a wire twist-tie from a bread wrapper or something similar. If the rally point is scrubbed then the party that is leaving can put a message clipped to a shrub or fence wire a foot off the ground. Why a foot? Because most people scan at a 5' level or at the ground. Plus, a foot keeps it from getting damp which is a possibility if the message stays there for any length of time.
NO, not an 8.5"-by-11" memo on bright-white paper. A few words scribbled on a scrap of paper torn from a fast-food bag is far better.
Since the rally point is likely to be large it is important that the late-comers have some idea of where to look for the dropped message. One possibility is to use the memory aid N-E-W-S as in "Look for the NEWS". The late-comers would first search the North side of the area, then the East and so on...
This is a game you can play with kids. You will be amazed at how sharp they are when they win a few skittles or a marshmallow upon finding the message.