Lightning Risk in the US: How FEMA Scores It and How to Prepare

Written by Dvir · Data: FEMA National Risk Index v1.20 · Updated August 4, 2026

Lightning strikes the United States about 25 million times a year — it is the most frequent hazard in the entire National Risk Index, with top counties logging 75–100 strike events annually. Yet it kills fewer Americans each year (recently around 10–20) than almost any hazard on this site, a public-safety success story built on one slogan. The remaining risk is stubbornly specific: people outdoors who didn’t go in, and property losses from fires, surges, and fried electronics. The NRI books roughly $1.6 billion in national expected annual loss to lightning (hazard code LTNG) across all 3,143 counties.

What counts as lightning risk

The NRI’s lightning hazard covers cloud-to-ground strikes and their direct consequences: casualties, structure fires, and damage to electrical systems and equipment. A bolt carries around 300 million volts and heats its channel to five times the sun’s surface temperature; what it touches, it ignites or destroys. Most victims are not struck directly — ground current radiating from a nearby strike, side flashes from trees, and conduction through wiring and plumbing account for most casualties, which is why “under a tree” and “on a corded phone” are classic case reports.

The behavioral profile is well documented: about 80% of US lightning victims are male, most are struck during leisure activities (fishing is the leading single activity), and the fatal window is disproportionately before and after the rain — when the storm seems far enough away.

How the NRI measures it

FEMA combines each county’s exposure (population and building value), annualized strike-event frequency from national lightning-detection network data, and historic loss ratios into an Expected Annual Loss scored 0–100 against all counties. Frequency dominates: the ranking traces America’s thunderstorm climatology across its biggest cities.

Where the risk concentrates

Florida is the US lightning capital, and the ranking shows it: Broward County (Fort Lauderdale) leads with a score of 100 and ~99 strike events/year, with Miami-Dade close behind (~98 events/year). The rest of the top five spans the thunderstorm belt: Honolulu County, HI (~77 events/year across a large exposed population), Harris County, TX (Houston, ~75/year), and El Paso County, TX (the monsoon-season desert Southwest). The broader high-frequency zone runs from Florida up the Gulf Coast and across the Southeast — Tampa Bay’s “Lightning Alley” sees more strikes than anywhere else in the country.

How to read your county’s score

Lightning risk is behavioral more than geographic: a high county score means more storm-hours per year during which the same universal rules apply. If you or your family spend serious time outdoors — golf, boating, fishing, youth sports, landscaping, roofing — frequency translates directly into personal exposure. For property, high-frequency counties justify surge protection and, for tall or isolated structures, engineered protection systems.

What actually reduces the risk

  • “When thunder roars, go indoors.” If you can hear thunder, the storm is within strike range (bolts routinely travel 10+ miles). Wait 30 minutes after the last thunder before resuming. This one rule is why US lightning deaths fell from hundreds a year to a dozen.
  • Safe shelter means a substantial building or a hard-topped vehicle. Pavilions, dugouts, tents, and golf carts are not shelter. Indoors, stay off corded devices and out of showers during the storm — wiring and plumbing conduct.
  • Coaches and organizers: have a lightning plan. Youth sports are a recurring casualty setting; designate shelter, assign a weather watcher, use a lightning app, and don’t restart early.
  • Protect the electronics: whole-house surge protection at the panel (now required in new construction by NEC 2020) plus point-of-use protectors for valuable equipment. Unplugging ahead of storms is still the only 100% protection.
  • Lightning rods work. A professionally installed lightning protection system (UL 96A / NFPA 780) doesn’t attract lightning; it gives a strike a safe path to ground. Worth it for tall, isolated, or high-value structures — and for barns; livestock losses are a steady rural cost.
  • If someone is struck: call 911 and start CPR immediately. Victims carry no charge, and prompt CPR has an excellent save rate — cardiac arrest is the mechanism of death, and it’s reversible.

How lightning deaths fell by 90 percent

Lightning is the rare American hazard with an unambiguous success story attached, and it is worth understanding because the mechanism was almost entirely educational rather than technological.

In the 1940s the US averaged roughly 300–400 lightning deaths a year. Through the second half of the century the number fell steadily, and in recent years it has hovered around 10 to 20. Some of that is demographic — a largely rural, agricultural workforce moved indoors — but the sharpest declines came after deliberate public-safety campaigns.

The National Lightning Detection Network, fully operational nationwide by the late 1980s, made it possible for the first time to know where and when strikes actually occurred rather than relying on reports. That data underpins the NRI’s frequency term and every lightning app on a phone today.

The “When Thunder Roars, Go Indoors” campaign, launched by the National Weather Service in the early 2000s along with National Lightning Safety Awareness Week, replaced a confusing set of folk rules — crouch, count the seconds, avoid metal — with a single unambiguous instruction. Deaths fell by roughly half over the following two decades. It is one of the highest-return public-health messages in American weather safety, and it cost almost nothing.

Youth sports protocols followed. After a series of fatalities at ball fields and golf courses, athletic associations, school districts, and course operators adopted mandatory suspension-of-play rules based on thunder or detection systems, plus the 30-minute wait. The remaining fatality cases in the US now cluster overwhelmingly among adults in unstructured outdoor recreation, where nobody is enforcing a rule.

The 2020 National Electrical Code began requiring whole-house surge protective devices in new and substantially renovated dwellings — the property-side equivalent of the same trend, driven by how much of a modern home is now electronics.

Season, timing, and geography

  • Season is overwhelmingly summer. June, July, and August account for the large majority of US lightning deaths, tracking thunderstorm frequency and the hours people spend outdoors.
  • Afternoon and early evening dominate. Peak strike activity runs roughly from mid-afternoon into the evening, when surface heating has done its work.
  • Weekends are deadlier than weekdays — not because of the weather, but because of fishing, boating, and ball games.
  • Florida is the national capital, and the corridor between Tampa and Orlando — “Lightning Alley” — records the highest flash density in the country, driven by sea-breeze fronts colliding over the peninsula almost daily in summer.
  • The Gulf Coast and Southeast follow, then the desert Southwest during the July–September North American monsoon, when Arizona and New Mexico see intense afternoon storms over dry ground.
  • The Mountain West contributes a distinct casualty profile: hikers and climbers caught above treeline in afternoon storms, where there is no substantial shelter within an hour’s descent. Colorado consistently ranks high in deaths despite modest strike counts.
  • The West Coast has the least lightning in the country, which is why California’s dry-lightning outbreaks — thunderstorms with little rain reaching the ground — are so consequential when they occur: they ignite hundreds of wildfires in terrain unaccustomed to any lightning at all.

Protecting the building

Most lightning property loss is not a dramatic strike to the roof. It is surge damage traveling in through power, cable, phone, and even water lines from a strike hundreds of feet away.

  • Install a whole-house surge protective device at the panel. A Type 1 or Type 2 SPD costs a few hundred dollars installed by an electrician, is now code for new construction, and is the single most cost-effective property protection for this hazard. It clamps the large transients; it does not stop everything.
  • Layer with point-of-use protection. Quality surge strips (with a joule rating and an indicator light, replaced every few years) on computers, televisions, and networking gear. Protect every conductive path into the device — a surge that cannot enter through the power cord will happily enter through the coaxial or Ethernet line.
  • Unplugging is the only complete protection. Before a forecast storm, unplug what you genuinely cannot replace.
  • Consider an engineered lightning protection system — air terminals, down conductors, and grounding, installed to UL 96A / NFPA 780 — for tall, isolated, or high-value structures: houses on ridgelines, barns, historic buildings, and anything with a tall tree or chimney nearby. It does not attract lightning; it provides a low-resistance path to ground so the current bypasses the structure. Barn strikes are a steady, underappreciated rural loss, both structural and in livestock.
  • Bond and ground properly. Most residential lightning damage traces to differences in ground potential between separately grounded systems (electrical, cable, satellite dish, well pump). A licensed electrician bonding them to a common ground is unglamorous and effective.
  • Solar arrays and heat pumps are increasingly common surge casualties. Ask your installer what surge protection is included; often the answer is none.

Insurance and medical realities

  • Lightning is a named covered peril on essentially every homeowners policy — for fire, structural damage, and damage to electronics and appliances from the strike. This is unusually clean coverage by the standards of this index.
  • Power surge coverage is narrower. Many policies cover surge damage only when lightning is the demonstrated cause, and exclude surges from utility switching or grid faults. Some carriers offer an equipment breakdown endorsement that fills the gap cheaply.
  • Document the event. Note the date, save the local storm report, and keep the damaged equipment until the adjuster has seen it. Claims for “fried electronics” without evidence of a nearby strike are commonly denied.
  • Tree damage follows the usual low sublimits, and a lightning-struck tree that later falls is a frequent secondary claim.
  • Medically, the mechanism is cardiac. Lightning kills primarily by inducing cardiac arrest, which is reversible. A lightning victim carries no residual charge and is safe to touch immediately. Call 911, start CPR at once, and use an AED if one is available — survival rates with prompt bystander CPR are good, and hesitation costs lives. Survivors frequently sustain long-term neurological effects — memory problems, chronic pain, sleep disruption — that deserve follow-up care even when the acute injury looks minor.

Before, during, and after

Before. Know the rule and teach it to everyone in the household: if you can hear thunder, you are within striking distance. Lightning routinely travels ten miles or more from its parent storm, and “bolt from the blue” strikes occur under clear sky ahead of and behind a storm. Install the surge protection. If you organize outdoor activities — youth sports, camps, work crews — write the lightning plan down: who watches the weather, what triggers suspension, where the designated shelter is, and who authorizes resumption.

During. Get inside a substantial building (one with wiring and plumbing to carry current to ground) or a hard-topped vehicle with the windows up. Dugouts, picnic pavilions, bus shelters, tents, and golf carts provide no protection whatsoever. Once inside, stay off corded phones and away from plumbing — do not shower or wash dishes — and keep clear of windows and doors. Wait 30 minutes after the last thunder before going back out; a large share of casualties occur after the rain stops and people assume it is over.

If you are caught outdoors with no shelter, the old crouching advice has been withdrawn because it does not meaningfully reduce risk. Move toward the best available shelter immediately: get off ridgelines and open water, out of open fields, away from isolated tall trees, and spread your group out so a single strike cannot injure everyone. Above treeline, descend.

After. Call 911 and begin CPR immediately for anyone struck; they are safe to touch. Check the house for fire, particularly in the attic and wall cavities, where a strike can smolder for hours — if you suspect a direct strike, call the fire department to check with a thermal camera even if nothing is visibly burning. Test smoke alarms, reset breakers, and inspect electronics and the HVAC system for damage that may only appear under load.

Sources

See the US counties with the highest lightning risk →

← All guides