Storm Safety

Part of Weather Forecasting

Recognizing dangerous weather and taking correct shelter action for lightning, floods, and tornadoes.

Lightning: The Most Common Killer

Lightning kills more people than tornadoes, hurricanes, or floods in most years. It is also the most preventable weather death.

The 30/30 Rule:

• If the time between lightning flash and thunder is under 30 seconds, you are in the danger zone — seek shelter immediately
• Wait 30 minutes after the last thunder before resuming outdoor activity

Lightning can strike 10-15 km ahead of a storm. If you can hear thunder, you are within striking range.

What to do:

• Get inside a substantial building (not a shed, tent, or open pavilion)
• If no building: get inside a vehicle with a metal roof (the metal conducts around you, not through you)
• If caught in the open: move to low ground, crouch low on the balls of your feet, minimize ground contact
• Stay away from isolated tall objects (single trees, poles, hilltops)

What to avoid:

• Open fields, ridges, hilltops
• Water (swimming, boating, fishing)
• Metal objects (fences, poles, tools, bicycles)
• Sheltering under a single tall tree (lightning targets the tallest object)
• Lying flat on the ground (increases ground current exposure)

Flash Floods: The Deadliest Storm Hazard

More people die from flooding than from any other weather event. Flash floods kill quickly because water rises faster than people expect.

Warning signs:

• Heavy rain upstream, even if your location is dry
• Rising water in streams and rivers
• Water changing color (brown, muddy — upstream erosion means heavy flow)
• Unusual sounds — roaring from upstream in a normally quiet stream
• Rain lasting more than 30 minutes at high intensity

Survival rules:

• Never cross flowing water above your ankles. Six inches of fast-moving water can knock you down. Two feet will float a vehicle
• Move to high ground immediately when water rises. Do not wait to see if it stops
• Never camp in dry washes, arroyos, or canyon bottoms — these can flood from rain you cannot see
• At night, flooding is more dangerous because you cannot judge water depth or speed

After flooding:

• Do not walk through standing floodwater (contamination, hidden hazards, downed power lines)
• Do not return to flooded structures until water has receded and foundations are inspected
• Discard any food contacted by floodwater

Tornado Recognition

Tornadoes give warning signs if you know what to look for. The time between recognition and arrival is typically 10-20 minutes — enough to reach shelter.

Warning signs (in order of urgency):

1. Dark, greenish sky — hail suspended in the storm gives the sky a green or yellow-green tint
2. Large hail — tornadoes often occur in the same storms that produce large hail. If hail arrives, tornado risk is elevated
3. Wall cloud — a low, rotating cloud base hanging below the main storm. This is where tornadoes form. If you see rotation, act immediately
4. Roaring sound — often described as a freight train. This means a tornado is very close
5. Sudden calm after intense storm — the eye of the storm’s rotation passing over. Danger is not over
6. Debris cloud at ground level — the tornado may be rain-wrapped and invisible, but a debris cloud at the base confirms it

What to do:

• Get to the lowest floor of a sturdy building
• Move to an interior room away from windows (closet, bathroom, hallway)
• Get under heavy furniture or cover yourself with a mattress
• If outdoors with no shelter: lie flat in a ditch or depression, protect your head
• If in a vehicle: do not try to outrun it. Stop, get out, and lie in a low area away from the vehicle

What NOT to do:

• Do not open windows (this was old, wrong advice)
• Do not shelter under highway overpasses (wind accelerates through the opening)
• Do not stay in a mobile home or trailer — these are destroyed by even weak tornadoes

Reading Storm Direction

Storms generally move from west to east (or southwest to northeast) in the mid-latitudes. But local topography and storm dynamics create exceptions.

Track a storm’s movement:

1. Pick a fixed reference point (tree, hilltop, building)
2. Note where the storm front sits relative to that point
3. Check again in 5 minutes
4. If the storm moves left or right of your reference: it will pass to your side
5. If the storm does not move left or right but gets larger: it is coming directly at you

Shelter Priority by Storm Type

Storm Type	Best Shelter	Acceptable	Avoid
Lightning	Interior of building	Metal-topped vehicle	Open areas, tall objects, water
Tornado	Interior room, lowest floor	Ditch or depression	Vehicles, mobile homes, overpasses
Flash flood	High ground	Upper floors of solid buildings	Low ground, basements, vehicles in water
Severe wind	Lee side of solid building	Dense forest (no dead trees)	Open areas, tents, under single trees
Hail	Any roofed structure	Vehicle	Open areas (large hail is lethal)

Building a Storm Plan

In any fixed camp or settlement, establish:

• Designated shelter locations for each storm type
• Warning signals that everyone recognizes (bell, horn, whistle pattern)
• Meeting point after the event for headcount
• Supply cache in shelter locations (water, first aid, light source)

Practice the plan. In a real emergency, people default to what they have practiced, not what they have been told.