Quick answer
An electromagnetic pulse, from a high-altitude detonation or an extreme solar event, threatens the big fragile things: transformers, transmission lines, and the grid they form. Your phone probably survives; the network it needs probably does not, possibly for a long time. Which means EMP preparation is really long-grid-failure preparation: two weeks of water, food, light, cash, and a radio. The honest answer is unglamorous, and it works for every version of the story.
Supply numbers are set for 4 people. Change your household size below and every quantity updates.
The grid
The actual vulnerable system
2 weeks+
Realistic planning target
Months
Large transformer replacement time
$30
The battery radio that answers most of it
What an EMP would actually unfold like
The event
No movie moment for most people: the power drops, and unlike every outage before it, nothing about the grid's restoration machinery is certain.
Hours 1 to 24
Information is the scarce resource. Cell service degrades as tower batteries drain. The battery radio becomes the household's one reliable window.
Week 1
Functionally identical to a major grid failure: water pressure, payments, and fuel all wobble. The household that prepped the grid kit runs on it.
The long tail
If large transformers were damaged, regional restoration is measured in weeks to months. Deep pantry and community are the real long-tail assets.
Play it out
One strange morning, three decisions
The lights go out and the story is unclear. Play it with a level head.
Scene 1 of 3
Months earlier. A video with dramatic music explains that an EMP will send America to the 1800s forever, and the presenter's solution is a $400 foil-lined bag collection for your electronics.
Prefer to read it straight through?
Scene 1
Months earlier. A video with dramatic music explains that an EMP will send America to the 1800s forever, and the presenter's solution is a $400 foil-lined bag collection for your electronics.
If you buy the bags. better safe than sorry: The bags arrive, the gadgets go in, and the actual gaps stay open: there is still three days of water in the house and the radio drawer is empty. Fear bought accessories; the boring kit that carries every grid scenario is still unbuilt.
If you spend the same $400 on the two-week grid kit: Water, shelf food, lights, a crank radio, cash, and a full propane tank. It covers hurricanes, ice storms, and grid failures of every cause, including the electromagnetic one. Protection that works across twenty scenarios beats protection against one.
Field note: The EMP-vulnerable layer is the grid, not your flashlight. Preparation that only helps in one scenario is usually marketing; the two-week kit is load-bearing in all of them.
Scene 2
9:47am on an ordinary Tuesday. Power drops, both cars' radios still work, but every station is carrying the same emergency tone. Your phone has bars, then does not.
If you drive around to see what's happening: Everyone with the same idea is also driving. Fuel is unbuyable with pumps down, intersections have no signals, and information is not out there on the roads anyway. You burn a quarter tank collecting rumors.
If you stay put, radio on, start the grid failure protocol: The battery radio catches the actual emergency broadcast. Tubs get filled while pressure holds, the fridge rule goes up, and the car keeps its half tank for when leaving means something. Calm plus information beats motion every time.
Field note: In any grid-down event, broadcast radio is the most resilient information channel that reaches households. A $30 battery radio outperforms a $1,000 phone with no network.
Scene 3
Day 4. Power is still out region-wide and official broadcasts talk about phased restoration without dates. Your neighbor is certain it was an EMP attack; your cousin texts from two states away that it was a cyber event. Nobody actually knows.
If you fall down the speculation rabbit hole with the neighbor: Three hours of theories later, no gallon of water has moved and the anxiety in the house has doubled. The cause is genuinely interesting and genuinely useless to your Tuesday: the household needs rationing math, not attribution.
If you run the house on what is true: supplies, rations, radio schedule: Inventory says nine days of comfortable margin, so water discipline starts now, not day nine. Radio checks twice a day, kids on scheduled jobs, speculation politely left at the door. Households that run on facts stay households.
Field note: In extended events, the cause matters to governments and the response matters to households. Ration early while options are wide, and let the radio, not the rumor mill, set your picture.
The EMP checklist, honestly
People in your household
One page per scenario: quantities resize in place, and the link you share always shows this plan.
Your head start
0 of 14 days covered
0 of 14 essentials on hand
Tick what you already own.Save this as your real plan →Supplies buy you days. Gear keeps those days livable. Most families discover they start around day 3.
| Item | For 4 people | Why it matters | Covers | |
|---|---|---|---|---|
| Water · 56 gallons total | ||||
| Bottled water, 24-pack cases | 11 cases (about 34 gal) | Sealed, portable, splits between rooms and the car. | Days 1 to 9 | |
| 5-gallon water jugs | 5 jugs | The cheapest gallons you can store. Fill spares before the event, not during. | Days 10 to 14 | |
| Water purification tablets | 1 pack | Turns suspect tap or tub water into drinking water after day 14. | Backup | |
| Food, no cooking required | ||||
| Canned protein: tuna, chicken, beans | 36 cans | Eats straight from the can when the stove is out. | No cooking | |
| Canned vegetables and fruit | 40 cans | Fluids and vitamins while the fridge is dark. | No cooking | |
| Peanut butter | 4 large jars | 2,650 calories per jar, no prep, kids will actually eat it. | No cooking | |
| Crackers, tortillas, granola bars | 8 boxes plus a dozen bars | The bread aisle empties first. These keep for months instead of days. | No cooking | |
| Oats and shelf-stable milk | 12 cartons plus a canister of oats | Breakfast without power, and the milk needs no fridge until opened. | No cooking | |
| Information, the scarce resource | ||||
| Battery or crank AM/FM radio | 1, plus spare batteries | Broadcast radio is the channel designed to survive grid loss. This is the EMP purchase. | Critical | |
| Printed contact and meetup card | 4 cards | If networks stay down, the family plan lives on paper: who goes where, who checks on whom. | Critical | |
| Paper maps of your region | 1 set | Navigation without GPS is a skill your glovebox can hold. | Backup | |
| Power, light, and news | ||||
| Flashlights or headlamps | 5 flashlights | One per person plus a spare. Candles start fires in dark houses. | All week | |
| Batteries in every size you use | 2 packs per size | The thing that runs out on day 2 if you guess. | All week | |
| Phone battery banks, fully charged | 2 banks | Your phone is your flashlight, radio, and lifeline. Top the banks up the moment trouble is forecast. | All week | |
| NOAA weather radio, battery or crank | 1 | When cell towers and wifi fail, official updates still reach you here. | All week | |
| When systems fail | ||||
| Cash in small bills | Two weeks of essentials worth | Every digital payment layer rides the grid. | Critical | |
| Full gas tank habit | Keep above half | Pumps are electric. Half a tank is a hundred-plus miles of options, always. | Habit | |
| Health and documents | ||||
| First aid kit | 1 | Minor injuries spike during cleanup, exactly when help is hardest to reach. | All week | |
| Prescription medications | 14-day supply each | Pharmacies reopen slowly. Ask your pharmacist about an emergency refill before you need it. | 2 weeks | |
| Documents in a waterproof bag | IDs, insurance, cash in small bills | ATMs and card readers die with the power. | Grab and go | |
| Manual can opener | 1 | Most of the calories above are locked inside cans without it. | Critical | |
You will notice this is the grid failure kit with a radio emphasis. That is the honest finding: the preparation that works for an EMP is the one that works for every long outage. Print this page to take it shopping.
In the app
Skip the panic, keep the plan
Provision Planner has a built-in EMP scenario that tracks the honest version: the two-week grid kit, the radio and cash layers, and how many days your real shelves cover. The app works fully offline, which is rather the point here.
Run the EMP scenarioEMP Attack scenario
Water
14 days
Food
17 days
Radio and cash layer
Ready
Offline access
On
Computed from your real inventory. Updates itself as things expire.
Frequently asked questions
Would an EMP really destroy all electronics?
No. Commission testing suggests most small, unplugged electronics would survive a high-altitude EMP; the serious vulnerability is long transmission lines and large transformers, which act as antennas. The realistic outcome is a long, wide grid outage, not dead flashlights, which is why this page is a deep grid kit.
Do I need a Faraday cage?
It is optional insurance, far down the list. A steel trash can with a sealed lid protects a spare radio and battery bank for almost nothing if you want the hedge. But no Faraday anything matters if the household lacks water, food, and cash for the outage that follows.
How likely is an EMP event?
High-altitude attack: genuinely low probability, high consequence. Extreme solar events that stress the same equipment: certain over a long enough horizon, with 1859 and 1989 as the famous precedents. The same preparation covers both, plus every mundane grid failure in between, which is what makes it rational.
Would cars stop working?
Mostly no. Real-world EMP testing on modern vehicles showed the large majority continue operating or restart. Fuel is the actual constraint, because station pumps need grid power. The half-tank habit answers that better than any hardening.
Explore more scenarios
Every scenario gets the same treatment: the event, the supplies, the timeline, and your number.
Scenario 07Grid Failure
Scenario 09Solar Storm
Scenario 06Power Outage
Scenario 13Food Shortage34 scenarios, one libraryBrowse them all →Go deeper: 2-Week Supply Plan for 4 People · Food Storage Calculator
Framing follows the EMP Commission's published findings and DOE grid resilience studies. This page deliberately avoids both panic and dismissal: the preparation described is load-bearing for all long-duration grid failures regardless of cause. Photography: NASA image library and Pexels, used under their respective licenses.