Hail Safety for People and Vehicles: What a Severe Thunderstorm Warning Means and Where to Shelter

Quick answer: The National Weather Service treats a thunderstorm as severe when it is capable of producing hail one inch in diameter (about the size of a quarter) or wind gusts of 58 mph or higher. A Severe Thunderstorm Warning means that kind of storm is occurring or is imminent, so you should take shelter now. Go to a small interior room on the lowest floor of a sturdy building and stay away from windows. If you are driving, delay the trip or pull over safely rather than trying to outrun the core of the storm. Move vehicles into a garage or carport before the storm arrives if you have time and it is safe to do so, and bring pets inside. Hail is only one hazard in these storms; lightning, flash flooding and sometimes tornadoes can accompany them, which is why this guide sits under our severe weather preparedness guide and next to lightning safety in the city and high-wind and severe thunderstorm safety for apartments.

Sources: National Weather Service severe thunderstorm definition and safety pages (hail one inch / quarter-size or winds 58 mph or higher; warning means the storm is occurring or imminent; interior room, lowest floor, stay away from windows; avoid driving through severe storms); NWS local hail-safety materials describing common size comparisons; Ready.gov thunderstorm, lightning and hail preparedness materials. Checked November 2026. This is general preparedness information, not legal, medical, engineering, insurance or emergency-management advice. Official guidance and local rules can change. Confirm current instructions from local officials and the agencies named here before you rely on a detail.

What Counts as Severe Hail, and What the Alerts Mean

Hail is frozen precipitation that falls from thunderstorms. Small stones can sting. Larger stones can break windows, dent vehicles, damage roofs and injure people or animals caught outside. The National Weather Service’s official severe-thunderstorm threshold for hail is one inch in diameter, commonly compared with a quarter. Wind gusts of 58 mph or higher also meet the severe definition, even if the hail is smaller.

A Severe Thunderstorm Watch means conditions are favorable for severe storms in and near the watch area. Use that time to change outdoor plans, check a reliable alert source, and decide where you will go if a warning follows. A Severe Thunderstorm Warning means a severe storm is happening or is about to happen where you are. That is the signal to shelter, not to stand on a porch and watch the sky. Watches usually cover a broader area and a longer period than warnings, which are more local and shorter. Treat official NWS definitions on weather.gov as the authority for the difference between a watch and a warning, and use our emergency alerts guide for how those messages can reach you.

Do not wait for a report of “golf-ball hail” before you move. A warning already means the storm is capable of producing severe hail or wind. Lightning frequency is not what triggers a severe thunderstorm warning, so a storm can be warned and still be dangerous in more than one way.

NWS offices sometimes describe hail by everyday objects (pea, marble, quarter, golf ball). Those comparisons are a communication tool. They are not a promise about what will hit your block. If you are a trained spotter reporting hail, follow current NWS reporting guidance rather than guessing.

Where to Shelter When Hail Is Falling

The core action is simple: get inside a sturdy building, go to a small interior room on the lowest floor, and stay away from windows. Hail and wind-driven debris can break glass. Putting more walls between you and the outside reduces that risk. Bathrooms, closets and interior hallways are common choices in a house or apartment if they do not have large windows.

If you are outdoors, do not shelter under a lone tree to “wait it out.” Get to a substantial building or, if that is not possible, a hard-top vehicle with the windows up, then reassess as soon as you can reach a better space. A vehicle is better than standing in the open, and it is still not as good as a sturdy indoor room. Convertibles, golf carts and motorcycles offer little protection.

Boaters should head to shore when thunderstorms threaten, following the same thunderstorm safety logic used for lightning. Parks, rooftop decks and exposed balconies are poor places to linger once a warning is out. Bring pets in before the storm, not after the first stones fall.

Schools, offices and stores should already have a severe-weather plan. If you are a visitor, follow staff instructions and move away from glass storefronts and skylights. Do not stand at the window to film.

Stay inside until the warning expires or a reliable official source says the threat has passed for your location. A pause in the hail does not always mean the storm is over. Some lines of storms can bring a second core, and a tornado can form with little extra notice. If a tornado warning is issued, switch to tornado sheltering: a small interior room or stairwell on the lowest floor you can reach, still away from glass. Our tornado safety guide covers the general home plan.

If You Are Driving, or Your Car Is Parked Outside

The safer traffic plan is to delay travel when a severe thunderstorm warning includes your route. If you are already on the road, do not try to “beat” the storm at high speed. Heavy rain can hide hail, flood a road in minutes, and cut visibility to almost nothing. Never drive through water that covers a road, even if it looks shallow; that is the same rule as in our flood safety guide.

If hail begins while you are driving and you cannot reach a sturdy building, slow down, increase following distance, and look for a safe place to pull off the road, away from trees that could shed branches and away from low spots that can flood. Keep windows up. Cover yourself with a coat, blanket or other padding if glass is a concern, and wait. Do not get out to inspect the paint during the fall.

Before a warned storm arrives, move cars into a garage or carport if you can do it with time to spare and without standing outside in the core of the storm. If you cannot move the vehicle, accept that cosmetic damage is secondary to getting people and pets inside. Afterward, watch for broken glass, and be careful opening doors if a window has shattered.

Motorcycles, bicycles and scooters should not be out in a warned hailstorm. If you are caught, get to a building first, then deal with the bike.

City parking is often uncovered. A hail plan for a household that street-parks is mostly an alert plan and a shelter plan, not a guarantee of a garage. That is one more reason to take watches seriously and to have more than one way to receive warnings, including Wireless Emergency Alerts and a NOAA Weather Radio as described in the alerts guide.

After the Hail, and How This Fits a Wider Thunderstorm Plan

Wait for the threat to pass before you go outside to look at roofs, cars or gardens. Broken glass, downed branches and slick walks are ordinary aftermath. If a power line is down, stay away and call the utility; treat it as live. Cleanup that involves trees, saws or debris has its own safety rules.

Check on neighbors who may need help getting inside next time, especially if they have limited mobility or did not receive the warning. Then document damage with photos for insurance when it is safe, and contact your insurer rather than guessing what a policy covers.

Hail is usually part of a thunderstorm package, not a standalone event. The same afternoon can bring lightning, flash flooding and damaging wind. A good household plan uses one alert habit, one indoor shelter, and a decision to delay travel, rather than a separate ritual for each hazard. Review that plan when the sky is quiet, including where kids and pets will go, and how you will hear a warning at night.

Do not use a landline phone or unnecessary electrical appliances if lightning is also a threat, a point NWS thunderstorm-safety materials have long emphasized. Battery lights are more useful than candles if the power fails.

If your building has a shared plan, learn it before storm season. If it does not, an interior stairwell or an interior room still beats an exterior window wall. After a close call, write down what was missing — a flashlight, a way to hear alerts in a back bedroom, a pet carrier — and fix those gaps while the memory is fresh.

Planning Ahead Without Turning It Into a Shopping Spree

A hail plan is mostly habits, not gear. You need a way to hear a warning when you are asleep or on a subway platform, a decided indoor room, and a bias toward delaying outdoor events when a watch is up. A flashlight, closed-toe shoes, and a towel for pets are useful if you have to move quickly at night. You do not need a special “hail kit” that duplicates a basic household kit.

If you work outside, ask your employer what the job-site rule is when a warning is issued. Construction, delivery, coaching and food-service patio work all have the same physics: glass, metal and open sky are the wrong place to wait. A short delay is cheaper than an injury.

After a damaging event, stay off damaged roofs unless you are qualified and it is safe. Insurance photos can wait until the lightning and hail have stopped. If a window is broken, keep people and pets away from the glass and cover the opening only when the storm has passed.

City buildings sometimes have windows that are hard to get away from in a studio. In that case, put as much interior space as you can between you and the glass, get low, and use a mattress, heavy cushions or a closet if you have one. The goal is distance from flying glass, not a perfect bunker.

Frequently Asked Questions

Does pea-size hail mean I can stay on the balcony?

No. Even smaller hail means a thunderstorm is already overhead, and lightning or a stronger core can follow. Go inside and stay away from glass.

Is a severe thunderstorm warning the same as a tornado warning?

No. A severe thunderstorm warning is issued for hail one inch or larger and/or winds of 58 mph or higher. A tornado warning means a tornado is occurring or imminent. Treat each on its own terms, and be ready to shift to tornado sheltering if that warning is issued.

Should I put my hands or a pillow on the car roof to "protect" it?

No. Get yourself to safety. A vehicle is a shelter option when a building is not available, not a project to save the paint during the fall.

Can hail happen in winter or at night?

Hail is a thunderstorm product and can occur whenever such storms occur, including after dark. An alert habit should work at night, not only on weekend afternoons.

Is a bus shelter or a gas-station canopy enough?

Those structures may get you out of the open, but they often have little protection from wind-driven hail and lightning. Get to a sturdy building as soon as you can.

When is it safe to go back outside?

When the warning for your location has ended and official information does not show another immediate core approaching. Then watch for debris, glass and downed lines.