Local Risks · Severe Thunderstorm
Severe thunderstorms are the most common significant weather hazard in the United States. Most households are less than 30 miles from one every year. The good news: a solid 72-hour kit already covers most of what you need.
Regional reality
The National Weather Service issues roughly 10,000 severe thunderstorm warnings each year. Unlike hurricanes or wildfires, severe thunderstorms don't respect geography. They strike the Gulf Coast, the Great Plains, the Ohio Valley, New England, and the Pacific Northwest. No region gets a pass.
The highest frequency zone in the country. Central Oklahoma, Kansas, Nebraska, and Iowa see dozens of severe events per season, with tornado-producing supercells from March through October. Hail over 1 inch in diameter is common enough that it doesn't make local news.
A year-round threat zone. The Southeast sees severe thunderstorms even in winter, driven by warm Gulf moisture. Florida averages more lightning strikes than any other state. The season never fully closes. Events are fast-moving and can catch residents without a watch-to-warning lead time.
Concentrated in summer, but intense. A single strong Derecho in 2012 knocked out power to 4.2 million customers across the mid-Atlantic for up to a week. The density of old-growth trees in residential neighborhoods makes wind damage to structures higher than in younger suburbs.
Know the difference
A Severe Thunderstorm Watch means conditions are favorable for severe storms in the area. It's a heads-up. Check your supplies, know where you'll shelter, and keep an eye on local radar.
A Severe Thunderstorm Warning means a storm producing wind over 58 mph or hail 1 inch or larger has been detected by radar or confirmed by a spotter. Take shelter indoors immediately.
How alerts reach you
Preparation beyond the basics
A complete 72-hour kit handles most of what a severe thunderstorm requires. These four areas add the thunderstorm-specific layer on top.
01
Lightning kills roughly 20 Americans per year and injures several hundred more. Most casualties happen outdoors in the 30 minutes before or after a storm's core passes.
The 30/30 rule is the practical standard. Count the seconds between a lightning flash and the thunder that follows. Divide by 5 to get the approximate distance in miles. If that number is 6 or less (30 seconds), seek shelter immediately. Wait 30 minutes after the last thunder before going back outside.
Safe indoors means:
If caught outdoors:
02
Hail causes more than $1 billion in vehicle damage each year in the United States. A hailstone the size of a golf ball (1.75 inches) falls at roughly 44 mph. At that speed, it dents steel and shatters glass. Most damage is concentrated in a path 3 to 7 miles wide.
If severe hail is forecast for your area and you have covered parking, use it. If you don't, understand what your auto insurance actually covers. Comprehensive coverage pays for hail damage; collision does not. Check your policy before storm season, not after.
Practical steps:
03
Thunderstorm-related outages and grid fluctuations are the leading cause of power surge damage to electronics. A surge can arrive through the power line, the phone line, and the cable or satellite connection simultaneously.
A surge protector handles momentary voltage spikes. An uninterruptible power supply (UPS) adds a battery buffer that keeps critical equipment running for several minutes after power drops, and conditions the power coming in. For any device you can't afford to lose mid-operation, the UPS is the right tool.
Where to start:
04
Straight-line winds in severe thunderstorms regularly reach 60 to 80 mph. At those speeds, mature trees with compromised root systems or internal decay become projectiles. In the Northeast and Southeast especially, old-growth residential trees are the primary cause of storm-related structural damage.
Most households treat tree risk as something to deal with after a storm. The practical move is a pre-season walk-around: identify trees within fall distance of your structure, and flag the ones showing warning signs.
Warning signs worth a call to an arborist:
Already covered
Flashlights, water supply, three days of food, a battery radio, and a household communication plan, including a written contact card, cover virtually every other aspect of a severe thunderstorm event. If your kit is complete, severe thunderstorm prep is mostly the four categories above. If it isn't, start there.
During the storm
A severe thunderstorm warning typically gives you 10 to 30 minutes. Most of what you need to do can be done in the first five.
Move everyone inside a fully enclosed structure. Close windows and exterior doors. This sounds obvious, but data shows most lightning fatalities occur in the 30-minute window before and after a storm, not at its peak, because people delay going in or go out too early.
If the storm is 15 or more minutes out and a garage or covered structure is nearby, move vehicles. If the storm is closer, stay inside. A damaged vehicle is replaceable. Driving into a severe storm to find a parking spot is not a reasonable trade.
Power fluctuations begin before the storm core arrives. Unplug televisions, computers, and gaming systems if they're not connected to surge protection. A UPS will handle the rest automatically. You don't need to do anything after it's plugged in.
Interior rooms on lower floors are the safest position. Lightning can travel through metal pipes and wiring in a structure. Avoid showers, sinks, and corded phones during active lightning. Move pets away from windows.
Keep your NOAA weather radio on. If the storm upgrades to a tornado warning or produces a confirmed tornado, you need that alert before you see the rotation. A weather radio will interrupt any broadcast with a tone alert. Watching from the window to see what's coming is not situational awareness.
The 30/30 rule applies on both ends. After you hear the last thunder, wait a full 30 minutes before going back outside. Lightning can and does strike several miles from a storm cell's visible edge, in what feels like clear air.
Recovery
Most thunderstorm damage is resolved faster than hurricane or ice storm damage, but the first hours after a severe storm require a methodical approach.
Before going outside, look through windows for downed power lines, leaning trees, and structural damage. A downed line that still has current looks identical to one that doesn't. The rule is simple: if you see a downed line, assume it's live and stay well clear.
If a power line has come down on or near your property, your job is to keep people away from it and call your utility company's emergency line. That's the whole protocol. Don't attempt to move the line. Don't drive over it. Don't let children or pets near it.
A closed refrigerator holds safe temperature for roughly 4 hours without power. A full freezer holds for 48 hours, a half-full one for 24. Open both as infrequently as possible. If power is out past those windows, follow the USDA rule: when in doubt, throw it out. Don't taste-test.
A tree limb on a roof creates a secondary hazard: interior water damage begins within hours, not days. If the structure looks compromised, photograph it thoroughly before touching anything, and call your insurance company's emergency line before starting any cleanup. Most policies require contact before repairs begin.
If you're running a generator during extended outage, place it at least 20 feet from any window, door, or vent — including your neighbor's. Carbon monoxide is odorless and the leading cause of post-storm generator deaths. If your CO detector alarms, leave the structure immediately. Don't try to find the source first.
Photograph all visible damage before any cleanup or repairs begin. Walk the exterior of your property and photograph trees, siding, windows, and roof from ground level. This documentation is the foundation of your insurance claim. More photos are always better than fewer.
Local resources
These are the primary official resources for severe thunderstorm preparedness in the United States. Bookmark the ones relevant to your county before storm season starts.
The primary source for watches, warnings, and county-level forecasts. The NWS local office for your area publishes storm summaries and damage reports after major events.
weather.gov →
The Red Cross publishes thunderstorm safety checklists and operates local disaster relief chapters that assist with immediate shelter and recovery resources after major events.
redcross.org →
FEMA's Ready.gov provides the official federal preparedness guidance for thunderstorms and lightning, including printable checklists and family plan templates that align with what you've built here.
ready.gov →
Find your state emergency management agency.
Every state has an emergency management agency that publishes region-specific severe weather guidance, county-level hazard maps, and local warning system information. Search "[your state] emergency management agency" to find yours. Many publish storm ready checklists specific to the hazards most common in your county.
Tier 01 · Survive
A completed First 72 Hours kit, including water, food, a battery radio, flashlights, and a household communication plan, covers the core of severe thunderstorm preparedness. If yours isn't done, that's the highest-value hour you can spend.