How do you navigate if your phone dies or loses signal? Set the phone up before you lose bars, with offline maps and a plan to stretch the battery, and carry a paper map and a baseplate compass you actually know how to use. With those two, you can find north, take a bearing, follow it one landmark at a time and correct for declination using a current value from NOAA. Closer to home, the navigation that matters most is knowing your way out before an evacuation order comes. This guide covers each step and the sources behind it.
This article is general safety information. In an emergency, call 911.
Step 1: Set Up Your Phone While It Still Has Bars
A phone is a good navigation tool right up until it isn't. The U.S. Forest Service puts it plainly: GPS devices "sometimes do not receive a signal or the battery fails," and cell phones "likely will not work because of a lack of signal" outdoors (U.S. Forest Service: If You Get Lost). So do the setup at home, on Wi-Fi.
- Google Maps: save an area for offline use. Driving directions work offline as long as the whole route is inside the saved area, but walking, cycling and transit directions don't work offline, and saved maps must be updated before they expire (Google Maps Help).
- Apple Maps: on iPhone, tap your picture or initials, then Offline Maps, then Add Offline Map. Automatic updates are on by default. The feature isn't available in every country or region (Apple Support).
- Red Cross First Aid app: its content is preloaded, so it works without reception or an internet connection (American Red Cross).
- FEMA App: real-time weather alerts and help locating emergency shelters. Download it while you're connected (Ready.gov).
Step 2: Make the Battery Last
The FCC and FEMA recommend dimming the screen, closing apps you aren't using and putting the phone in airplane mode when you don't need it (FCC/FEMA communication tips). Turn on Low Power Mode on iPhone (Apple Support) or Battery Saver on Android (Android Help); both cut background activity.
One more tip from the FCC: if you have no signal bars at all, a phone keeps draining its battery as it searches for a signal. Turning it off stops that. The FCC also suggests keeping extra batteries, a solar charger or a car charger on hand.
Step 3: Know the Parts of a Baseplate Compass
When the screen goes dark, a paper map and a compass take over. The Forest Service lists "a compass that you know how to use" and appropriate maps among the essentials for any outing. Here's what each part of a common baseplate compass does (National Park Service compass lesson; USGS):
| Part | What it does |
|---|---|
| Baseplate | The clear plate you hold flat in your hand |
| Direction-of-travel arrow | Etched on the baseplate; point it where you want to go |
| Rotating dial | Marked in degrees, 0 to 360; turn it to set a bearing |
| Magnetic needle | The red end points toward magnetic north |
| Orienting arrow and lines | Engraved on the floor of the housing; they turn with the dial |
| Index line | Where the dial meets the travel arrow; read your bearing here |
The one move to remember is "red in the shed": the red end of the needle sits inside the orienting arrow. Always hold the compass level and away from metal so the needle can swing freely.
Step 4: Find North and Take a Bearing
A bearing (also called an azimuth) is a direction in degrees, measured clockwise from north: 0 is north, 90 is east, 180 is south and 270 is west (National Wildfire Coordinating Group).
To find north, turn the dial until N (0) sits at the index line, then turn your body until red is in the shed. The travel arrow now points to magnetic north.
To take a bearing from a landmark:
- Hold the compass level and point the direction-of-travel arrow at the landmark.
- Turn the dial until the orienting arrow lines up with the red end of the needle.
- Read the number at the index line. That's your bearing.
To take a bearing from a map, lay the edge of the baseplate along a line from where you are to where you're going, with the travel arrow pointing toward your destination. Without moving the baseplate, turn the dial until the orienting lines match north on the map (USGS). That's a true bearing, which you'll adjust for declination in Step 6.
Step 5: Follow It One Landmark at a Time
With your bearing set, hold the compass level and turn your body until the red needle sits in the orienting arrow. Pick a tree or boulder in line with the travel arrow, walk to it, then check your bearing and pick the next one (Scouting America). Practice on a short, familiar trail before you rely on it.
Step 6: Correct for Declination, the Right Way
A compass points toward magnetic north; a map is laid out to true north. The angle between them is declination. NOAA counts east declination as positive and west as negative, and the value varies by location and changes over time (NOAA NCEI). That's why the number printed on an older map may be out of date. If your USGS map is more than 15 years old, USGS advises getting a current figure (USGS). Get one for your location and date from NOAA's free magnetic field calculator.
| Converting | East declination | West declination |
|---|---|---|
| Compass to map (magnetic to true) | Add | Subtract |
| Map to compass (true to magnetic) | Subtract | Add |
A worked example from USGS: with declination 10 degrees east and a destination due north on the map, you dial 350 degrees on a compass without adjustable declination (USGS). Wildland fire crews remember map to compass as "East is least, West is best" (NWCG).
Some compasses let you set declination once. After that, the number at the index line reads as a true bearing. Recheck the local value whenever you travel somewhere new.
Step 7: At Home, Know Your Way Out
For many families, the navigation that matters most is an evacuation. Ready.gov notes that many states have designated evacuation zones and predetermined routes; look yours up on your state and county emergency management websites, and sign up for local alerts while you're there (Ready.gov: Evacuation).
- Know alternate routes and other ways out of your area besides your car.
- Pick several places to go in different directions, such as a friend's home in another town or a motel.
- Plan for pets. Most public shelters allow only service animals.
- Keep half a tank of gas in the car at all times, and fill up if an evacuation seems likely. Gas stations may be closed or unable to pump during outages.
- When it's time, follow local officials and recommended routes. Don't take shortcuts; they may be blocked.
Never drive into floodwater. One foot of moving water can sweep your vehicle away (Ready.gov: Floods). Turn Around, Don't Drown.
Frequently Asked Questions
Does Google Maps work without cell service?
Partly. If you've saved an offline area, Google Maps can give driving directions as long as the whole route is inside it. Walking, cycling and transit directions aren't available offline, and saved areas expire if they aren't updated.
What does "red in the shed" mean?
It's a memory aid for the key compass move: turn the dial, or yourself, until the red end of the magnetic needle sits inside the orienting arrow. Then the travel arrow is lined up with your bearing.
Do I add or subtract declination?
Going from compass to map, add east declination and subtract west. Going from map to compass, subtract east and add west. Get a current value for your location from NOAA's magnetic field calculator.
How much gas should I keep in my car for an evacuation?
Ready.gov recommends keeping half a tank at all times, and a full tank if an evacuation seems likely.
Build Your No-Signal Kit
A baseplate compass, a paper map of the area, a charged power bank and a ready bag cover most of what's above. Browse our navigation tools, batteries, packs and chargers and go-bags, and read Pillar 8: Navigation for the bigger picture.
