Severe thunderstorms cause more annual damage in the US than hurricanes in many years. They bring damaging winds (58+ mph), hail, lightning, and tornado spin-ups.

Before the Storm

• Charge phones and power banks
• Secure outdoor furniture and trash bins
• Trim dead branches overhanging the house
• Test NOAA weather radio
• Identify interior room on lowest floor (no windows)

During the Storm

• Go indoors immediately — "When thunder roars, go indoors"
• Avoid windows, porches, and garages
• Don't use corded phones or plumbing
• If driving, pull over away from trees and power lines — don't touch metal inside the car
• If a tornado warning is issued, move to interior room or basement

Power Outage Response

• Report downed power lines — assume they are live
• Keep refrigerator closed (4-hour food safety window)
• Use battery lights instead of candles when possible

Full guide: Power Outage Survival Guide

Understanding Severe Thunderstorm Risks

A thunderstorm becomes "severe" when it produces hail ≥1 inch, wind gusts ≥58 mph, or a tornado. Straight-line derecho winds can down trees across a 200-mile path — knocking out power to millions for days. In 2020, a derecho caused an estimated $11 billion in damage across the Midwest alone.

Lightning kills an average of 20–30 Americans per year. Strikes can occur 10 miles from rainfall — blue sky overhead does not mean safety.

Regional Prep Differences

Home Hardening Checklist

• Install surge protectors on electronics — whole-house surge devices protect HVAC and appliances
• Trim branches within 10 feet of roof lines
• Secure patio furniture before storm season (March–April in most regions)
• Label electrical panel circuits now — you'll need this in the dark
• Store a battery-powered NOAA radio in the kitchen, not the garage

Tornado Spin-Up Warning Signs

Severe thunderstorms can produce tornadoes with little warning. Watch for:

• Greenish-black sky color
• Wall cloud or rotating cloud base
• Hail followed by dead calm
• Loud continuous roar (not individual thunder claps)

If observed, move to the lowest interior floor immediately. See our Severe Thunderstorm Prep guide.

After the Storm

• Inspect roof and siding for hail damage (document for insurance)
• Restock used batteries and power banks
• Check on neighbors, especially elderly residents

Bottom Line

Severe thunderstorms are short but violent. A charged radio, interior shelter plan, and power backup handle most scenarios.