What should you do if you are caught in a rip current?

A rip current is water returning seaward through a narrow channel after waves have piled it up on the beach, and it is a surface flow — it does not pull anyone downward. Typical speeds are around half a metre per second, which is faster than most people can swim against, and the strongest can exceed two metres per second. That is why exhaustion from fighting the current, not the current itself, is the mechanism behind the roughly one hundred rip-related drownings a year in the United States. Because rips are narrow, swimming parallel to the shore for a short distance usually clears the channel, after which the normal shoreward push of the waves does the work. Floating and signalling is a valid alternative for a tired or weak swimmer, since rips weaken beyond the surf zone rather than continuing out to sea.

What changes the figure

• Rips are surface currents; nothing about them pulls a person under
• Swimming parallel to the beach clears a channel that is usually tens of metres wide
• Floating and signalling conserves energy and is safer than fighting the flow

A rip current is a horizontal surface flow. The belief that it drags swimmers beneath the surface is wrong and leads people to fight it.

Physiology, not instruction. Every figure here is a population range under particular conditions, and individual variation is large — temperature, exertion, fitness and health move all of them substantially. Nothing on this page is medical advice.

Situations

• Can you survive a plane crash? Usually — across all US airline accidents studied, more than 95 per cent of occupants survived.
• How long do you have to escape a sinking car? Usually 30 seconds to a couple of minutes of floating — and the window is the way out, not the door.
• Can quicksand pull you under? No. Quicksand is roughly twice as dense as a human body, so you float — you sink to about waist depth and stop.
• How far from a nuclear blast do you have to be to survive? It scales with yield: for a one-megaton airburst, survival is unlikely within about 5 km and likely beyond about 10-12 km.
• How long can you survive in a hot car? Under an hour on a warm day for a child — the interior gains about 20 °C in the first ten minutes.
• How long does it take to drown? Under a minute to lose consciousness — and it is almost silent, which is why so many drownings happen in sight of others.
• What happens if a lift cable snaps? Essentially nothing — lifts hang from multiple ropes and have a speed-triggered brake that grips the rails.
• What height can you survive falling from? Survival is common below about 6 metres and rare above 20 — but people have survived falls from thousands.
• How likely are you to survive a shark attack? Very likely — of roughly 60 to 80 unprovoked bites worldwide each year, fewer than ten are fatal.
• What happens if you fall into lava? You would not sink — lava is about three times denser than a body — but you would not survive the heat either.
• Could you survive inside a whale? You cannot be swallowed by almost any whale — their throats are too narrow — and a stomach offers no air.
• How long do you have to escape a burning house? Around three minutes from the alarm sounding in a modern furnished home.
• Can you survive a tsunami? Yes, by moving inland and uphill immediately — 30 centimetres of moving water can knock an adult off their feet.
• How long can you survive in a sealed container? Carbon dioxide becomes dangerous long before oxygen runs out — a few hours in a cubic metre of air.