Thunderstorm & Lightning Safety: Preparedness Guide

Lightning kills approximately 20 Americans annually and injures hundreds more: making it one of the leading weather-related causes of death. But thunderstorms pose broader hazards beyond lightning: hail, high straight-line winds (up to 100 mph in severe supercells), flash flooding, and the power outages and electrical surges that follow. Thunderstorm preparedness combines lightning safety practices, outdoor exposure reduction, home electrical protection, and the supplies needed to manage the aftermath of a severe storm. This guide covers when to take shelter, how to protect your home and electronics, and what to have ready when a severe thunderstorm rolls through.

Lightning Safety: The Core Rules

• Seek substantial shelter: A fully enclosed building with plumbing and electrical wiring is the safest option: the grounding system distributes lightning energy. A hard-top vehicle (metal roof, windows up) is second-best. Open-sided shelters, tents, pavilions, and convertibles provide no lightning protection.
• Lightning can strike from clear skies: “Bolts from the blue”: lightning discharges that travel horizontally from a storm and strike up to 25 miles away from the thunderstorm: are real and documented. Clear sky above you is not safety if a thunderstorm is within range.
• Stay off high ground: Hilltops, ridgelines, open fields, and mountain summits dramatically increase strike risk during thunderstorms
• Avoid water: Water conducts electricity; get out of swimming pools, lakes, and off boats immediately when lightning is in the area
• Avoid tall isolated objects: Single tall trees, telephone poles, fence lines, and metal structures attract strikes; stay away and do not shelter under tall isolated trees

Outdoor Thunderstorm Safety by Activity

Hiking and Backpacking

• Check weather forecasts before heading out; avoid above-treeline travel in afternoon hours (peak thunderstorm development time in mountain terrain)
• If caught above treeline: descend immediately; avoid ridgelines and peaks; get below the ridge by any means possible
• Lightning crouch: if caught in the open with no shelter, crouch low on the balls of your feet, feet together, hands over ears, and minimize contact with the ground: do not lie flat (ground current from nearby strikes)
• Separate from your group by 50+ feet: a strike that hits one person can travel to others standing close together

Golf and Sports Fields

• Metal golf clubs are not significantly higher risk than anything else you’re holding: the real risk is being in an open field during a thunderstorm
• Most US golf courses and sports complexes have lightning warning systems (sirens, horns): obey them; don’t wait to finish a hole
• Go to a permanent structure; restroom buildings at parks are acceptable; open dugouts and picnic pavilions are not

Boating and Water Activities

• Get off the water before the storm arrives: lightning over water has a much larger lethal radius than on land
• A boat’s mast or antenna is typically the highest object on the water: it will attract lightning; even boats with lightning protection systems can sustain electrical damage and injury to occupants
• If caught on the water: get to shore if possible; go below deck on larger vessels; everyone should avoid contact with metal and stay low

Indoor Safety During Thunderstorms

• Avoid plumbing: Do not shower, bathe, wash dishes, or use sinks during a thunderstorm: lightning can travel through plumbing; multiple deaths per year result from bathing during thunderstorms
• Avoid corded electronics: Do not use wired telephones or touch wired electronic equipment: lightning surge can travel through wiring; use battery-operated or wireless devices only
• Stay away from windows and exterior walls: Lightning can travel through window frames and enter through exterior wall penetrations
• Unplug valuable electronics before the storm arrives: surge protectors do not guarantee protection from a direct strike or nearby ground strike; unplugging is the only complete protection
• Don’t handle metal objects: Stay away from metal fencing, pipes, railings, and similar conductors

Power Surge Protection

Thunderstorms cause power surges that can destroy electronics connected to the electrical grid. A whole-home surge protector provides comprehensive protection; individual power strips provide partial protection:

• Whole-home surge protector: Installed at the electrical panel; protects all circuits in the home from large surges; a licensed electrician installs these in 1–2 hours for approximately $200–400 installed; highly recommended for homes with expensive electronics or appliances
• Point-of-use surge protectors: Power strips with surge protection capacity rated in joules (minimum 1,000 joules; 2,000+ preferred); protect individual devices; do NOT use extension cords without surge rating for TVs, computers, and gaming systems
• Uninterruptible Power Supply (UPS): Battery backup that smooths power during micro-outages and surges; essential for computers and network equipment; provides time to save work and shut down gracefully during outages
• Unplug is safest: No surge protector provides 100% protection from a direct or nearby strike; unplugging computers, TVs, and appliances before a storm is the only complete protection

Hail & High Wind Preparation

Hail

• Move vehicles into a garage before a hail storm: hail larger than 1 inch causes significant damage to vehicle exteriors and glass
• Skylights and greenhouses are vulnerable to large hail; close interior shutters if available
• Hail insurance claims typically require documentation of damage size (photograph hailstones next to a ruler) and may require timely reporting: contact your insurer within 24–48 hours of a hail event

Straight-Line Winds

• Severe thunderstorms produce straight-line winds that can exceed 100 mph: equivalent to a Category 2 hurricane in gusts: without the organized rotation of a tornado
• Bring outdoor furniture, grills, decorations, and any portable items inside before a severe thunderstorm watch
• Avoid parking under trees during high-wind thunderstorms: falling branches and toppled trees are a primary cause of vehicle and property damage
• Stay away from windows during high-wind events: glass failure from debris impact is a real risk at extreme wind speeds

Thunderstorm Preparedness Supplies

• NOAA weather radio (battery/crank) with SAME alert: for severe thunderstorm and tornado warnings
• Flashlights × 2 + headlamps × 1 per person: thunderstorm power outages are common and often unannounced
• Lithium AA batteries × 24: for flashlights and radio
• LED lantern × 1: for area lighting during multi-hour outages
• Portable power bank (10,000 mAh+): for phone charging during outages
• Surge protectors (2,000+ joule rated) for all major electronics
• UPS (uninterruptible power supply) for computers and network equipment
• First aid kit: for post-storm injuries from debris
• Work gloves × 2 pairs: for clearing fallen branches
• Chainsaw or manual bow saw: for clearing storm debris from access routes
• Tarps × 2 (20 ft × 20 ft) + rope: for covering roof damage until repairs are made
• Rope and bungee cords: for securing tarps and temporary outdoor repairs
• 3-day food and water supply: extended outages can follow severe storms

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