Flash flood safety

The one rule

Turn Around, Don't Drown.

Six inches of moving water knocks you off your feet. Twelve inches carries away a small car. Two feet floats a pickup. Do not drive or walk through flooded roadways. Ever.

Over half of flood fatalities are vehicle-related. Most of those happen at night on rural roads where the driver could not see how deep the water was.

How flash floods happen

• Slow-moving thunderstorms dumping 3+ inches of rain per hour.
• Training storms (multiple cells over the same area).
• Steep terrain that concentrates runoff.
• Urban surfaces (concrete, roofs) that don't absorb.
• Saturated ground from prior rain.
• Snowmelt combined with rain.
• Dam or levee failure (rare but catastrophic).
• Ice jams on rivers.

Warning terminology

If you're driving

1. Never drive into any water of unknown depth.
2. Never drive around road barriers.
3. If your vehicle stalls in water, abandon it — vehicles float once water reaches doors.
4. Get out through window if door won't open due to water pressure.
5. Get to the highest ground you can reach.
6. Call 911.

If you're on foot

1. Never walk through moving water above ankles.
2. Use a stick to probe depth.
3. Never enter flowing storm drains, culverts, or creeks.
4. Watch for downed power lines — assume every wire is live in floodwater.
5. Avoid standing water for days after — sewage contamination is universal.

If you're at home

1. Move to upper floor if possible.
2. If trapped: signal from a window with a bright cloth, not attic.
3. If you must attic-shelter: bring an axe or hatchet to break through roof if needed.
4. Fill bathtub with clean water for drinking.
5. Turn off electricity and gas at the main.
6. Do NOT try to save vehicles — save yourself.

Deadliest US flash floods

• 1889 Johnstown flood — 2,209 dead. Dam failure.
• 1972 Rapid City flood — 238 dead. Overnight thunderstorm.
• 1976 Big Thompson Canyon — 144 dead. Canyon compression.
• 2013 Colorado floods — 10 dead, but $2B damage across Front Range.
• 2017 Hurricane Harvey — 68 flood dead in Texas.
• 2022 Kentucky flooding — 45 dead, Appalachian valleys.
• 2024 Hurricane Helene — over 200 dead in Appalachia, most from flooding.

Preventable dangers

• Low-water crossings on rural roads — thousands nationwide.
• Highway underpasses that flood rapidly.
• Basements below street level.
• Manufactured homes in flood zones.
• Campgrounds in canyon terrain.
• Slot canyons in the Southwest.
• Steep drainages in wildfire burn scars.

Flood insurance

• Standard homeowners does NOT cover flood.
• NFIP (National Flood Insurance Program) is federally backed.
• Private flood policies available.
• 30-day waiting period for new policies.
• Check FEMA flood map for your address (msc.fema.gov).
• High-risk zones have mortgage requirements for coverage.
• Even low-risk zones can flood — 25% of flood claims come from low-risk areas.

Learn more

• Tornado safety checklist
• Tornado recovery guide
• Lightning safety guide
• Tornado emergency kit