If your evacuation plan involves a vehicle, and for most families it does, that vehicle deserves its own dedicated radio setup rather than relying on whatever handheld happens to be in the console.
A Mobile Radio Beats a Handheld From Inside a Vehicle
A vehicle’s metal body significantly attenuates a handheld’s signal from inside the cabin, while a mobile radio with an externally mounted antenna and more available power output performs dramatically better. If evacuation comms matter to your plan at all, a permanently mounted mobile is worth the investment over relying on a handheld through a window.
Antenna Mounting Without Drilling Holes You Regret
A magnetic mount antenna on the roof is the easiest reversible option and performs perfectly well for this purpose, avoiding a permanent hole in a vehicle you might sell or trade in later. A trunk lip or hatchback mount is the next step up if you want something more permanent without a drilled hole at all.
Power That Survives the Vehicle Being Off
Wire the radio so it can run without the engine idling the whole time, either through a dedicated auxiliary battery or a proper fused connection direct to the vehicle’s battery rather than a cigarette lighter socket. Running the engine purely to power a radio wastes fuel you may need for actual driving.
What to Actually Program In Before You Need It
Load your family’s GMRS and ham simplex frequencies, local repeaters, and NOAA weather channels into the mobile’s memory ahead of time, following the same running GMRS and ham together framework I cover in running GMRS and ham radio together. Programming this under stress during an actual evacuation is exactly the scenario you’re trying to avoid.
For the fuller picture on building real emergency communications capability, see my Emergency Communications and Preparedness pillar page.