Weather Safety & Extremes Guide

Hyper-local safety thresholds, biological risk indexes, and emergency response guidelines for extreme weather conditions.

Severe Storms & Tornado Safety

🌪️ Tornado Preparedness & Shelter

Tornadoes can develop in seconds during severe thunderstorms. Knowing the difference between alerts and having a shelter plan saves lives.

Tornado Watch: Conditions are favorable for tornadoes. Stay alert and monitor local radar.
Tornado Warning: A tornado has been spotted or indicated by radar. Take shelter immediately!
Best Shelter: Basement, storm cellar, or an interior room on the lowest floor (bathroom/closet) away from windows.
Mobile Homes/Vehicles: Never stay in a mobile home or car during a tornado; seek a sturdy building or low ground ditch.

⚡ Lightning Safety Rules

Lightning can strike up to 10 miles away from the main rain shaft of a storm.

⚡ "When Thunder Roars, Go Indoors!" If you can hear thunder, you are close enough to be struck by lightning.

30/30 Rule: Go inside when you hear thunder; wait 30 minutes after the last thunderclap before resuming outdoor activities.
Indoors: Avoid corded phones, electrical equipment, plumbing/showers, and windows/doors.
Outdoors: Never shelter under isolated trees. Avoid open fields, metal fences, and water bodies.

Flooding & Heavy Rain Safety

🌊 Flash Flood Hazards

Flash flooding is the #1 weather-related killer in the United States. Just a small amount of moving water can sweep cars and adults away.

🚗 "Turn Around, Don't Drown!" Never drive through flooded roadways. High water hides washed-out roads and sinkholes.

6 Inches of Water: Can knock down an adult or cause control loss in cars.
12 Inches of Water: Will float small cars and sedans.
2 Feet of Water: Can carry away trucks and large SUVs.

💨 Severe Thunderstorms & High Winds

Straight-line winds from severe thunderstorms can reach speeds over 60–80 MPH, causing damage equivalent to a tornado.

Severe Thunderstorm Watch: Severe storms with 58+ mph winds or 1"+ hail are possible.
Severe Thunderstorm Warning: Dangerous wind/hail is occurring or imminent. Move indoors.
Flying Debris: Move away from windows; take shelter in interior rooms to avoid falling trees or broken glass.

Summer Weather Safety & Heat Extremes

Heatstroke & Heat Index Thresholds

The National Weather Service Heat Index measures how hot it actually feels when relative humidity is factored with air temperature (calculated for shady conditions; full sunshine can increase values by up to 15°F).

80°F – 90°F (Caution): Fatigue possible with prolonged exposure and physical activity.
90°F – 105°F (Extreme Caution): Sunstroke, heat cramps, and heat exhaustion possible with prolonged activity.
105°F – 130°F (Danger): Sunstroke, heat cramps, or heat exhaustion likely; heatstroke possible with prolonged exposure.
130°F+ (Extreme Danger): Heat/sunstroke highly likely with continued exposure.

🚨 Heatstroke Signs & Symptoms: Body temperature above 103°F; hot, red, dry or damp skin (no sweating); rapid, strong pulse; throbbing headache, dizziness, nausea, confusion, or loss of consciousness. This is a medical emergency—call 911 immediately.

Sunburn Timing by UV Index

Ultraviolet (UV) radiation causes cumulative skin damage. Unprotected fair skin (Skin Type II) experiences damage and visible sunburn within specific timeframes depending on the live UV Index:

UV Index	Exposure Category	Time to Burn (Fair Skin)
0 – 2	Low (Green)	60+ minutes
3 – 5	Moderate (Yellow)	30 – 45 minutes
6 – 7	High (Orange)	15 – 25 minutes
8 – 10	Very High (Red)	10 – 15 minutes
11+	Extreme (Violet)	Less than 10 minutes

Prevention: Always apply broad-spectrum SPF 30+ sunscreen, wear UV-blocking sunglasses, and seek shade during peak solar hours (10 AM – 4 PM).

Winter Weather Safety & Cold Extremes

Frostbite Risks & Wind Chill Timelines

Wind chill strips away the thin layer of warm air insulating your body. As wind speeds increase and temperatures drop, exposed skin freezes rapidly:

Wind Chill 15°F to 0°F: Low risk, but prolonged exposure can cause discomfort.
Wind Chill 0°F to -18°F: Frostbite possible on exposed skin in 30 minutes.
Wind Chill -19°F to -47°F: Frostbite possible in 10 minutes or less on exposed skin.
Wind Chill -48°F or lower: Frostbite possible in 5 minutes or less. Extreme danger.

❄️ Frostbite Signs & First Aid: Numbness, loss of feeling, and pale, white, or waxy gray skin tone. First Aid: Gradually warm the area using body heat (do not rub or use direct intense heat which causes tissue damage).

Hypothermia Progression & Onset

Hypothermia occurs when your core body temperature drops below 95°F (35°C). It can set in within minutes to hours depending on wind, moisture, clothing, and activity level.

Stage 1 (Mild - 90°F to 95°F): Intense, uncontrollable shivering, cold/numb hands, stumbling, and mild confusion.
Stage 2 (Moderate - 82°F to 90°F): Shivering stops (critical warning sign), confusion deepens, slurred speech, slow/weak pulse, and muscle rigidity.
Stage 3 (Severe - Below 82°F): Unconsciousness, loss of reflexes, shallow/stopped breathing, and cardiac arrest risk.

⚠️ Emergency Treatment: Move the victim to a warm, dry shelter immediately. Remove wet clothing, wrap them in warm blankets, and provide warm, non-alcoholic drinks if conscious. Seek emergency medical assistance right away.

For more information on how you can prepare, visit ready.gov.