In order to have a safe journey, you need to equip yourself with the knowledge you need to protect yourself against some unexpected hazards. The following article will cover concepts, definitions and tricks to survive if you are unlucky enough to fall into this “death flow”.
What is off-shore flow?
Rip Current is offshore, reverse flow. This is a long and narrow flow, flowing from the coast to the sea, often appears in the rainy season.
Mechanism of offshore formation.
Basically waves will hit and bring water to shore. But when the seawater is brought continuously to the shore, it will gather into a stream going straight to the sea, then the offshore stream formed.
This flow occurs in dip waves, often due to the sea terrain. This area offshore is often blocked by coral or sand, reefs, when the waves hit will put water into a deep creek, then pour back to the sea.
Off-shore flows are usually quite narrow, ranging from 1 to 3 meters, but sometimes as wide as a dozen meters, stretching to hundreds of meters offshore. This is a very powerful and dangerous flow, with a wave velocity of 0.5 to 1 m / s, but sometimes up to 2.5 m / s. At this time, even swimming pool operators can not swim upstream. According to statistics, there are hundreds of drownings on the beaches each year because of this flow.
There are three types of offshore flows:
– Flash Rip Current: the flow formed, disappearing rapidly due to the decrease of sea level and the height of the wave rising suddenly.
Fixed Rip Current: formed by sea water blocked by two sand lines, can last for several days to weeks, even months.
Permanent rip current is formed due to the terrain of the sea. In coral reefs, this stream may exist permanently.
How to determine offshore flows
Rip Current can appear anywhere wave, including large lake (in Vietnam has not recorded any case). But to identify it is not easy for the unknown. The photos below may help us identify this vortex.
Can be determined when the water is stirred, bubbly, or slightly bloated.
The reverse flow is usually carried out by seaweed and other floating particles such as rubbish, forming a stream heading offshore.
The offshore stream also stirred sand from the bottom so if you suddenly see the water is more opaque than the surrounding areas, stay away.
A fault in the wave is also a sign of the offshore flow.
Here is a video of “time-lapse” showing the direction of the offshore flow (the deep blue sea water dyed in the sea):
Secret to get out of the water
Rip Current can suddenly appear at speeds from 0.3 to 0.6 m / s and usually will not show any signs. But once it enters and is swept away, this flow can quickly “accelerate”, reaching 1 – 2.5 m / s, at which point, no one can escape this vicious cycle.
But when it comes to the vicissitudes of death, try to do the following:
Do not panic. This is the most important thing. The feeling of being washed off the shore is certainly bad and horrible, but try to stay calm. The shore pull will not suck you down but only take you away from the shore. And usually, instantaneous flow takes you 30 meters offshore.
Do not swim upstream. Do not try to swim upstream from the water because most of the drowning cases are due to the reverse flow not because of being sucked down but because the victims too panic and try to swim upstream.
This is unlikely, because with the speed of 2.5 m / s, whether it is Michael Phelps – the American sailor with many world records – will also be exhausted and drowned.
Swim across the coast. Instead of trying to swim upstream, try to swim parallel to the shoreline, ie, perpendicular to the flow. After getting out of the whirlpool, cross the corner and head to the shore.
Follow the flow. For those who do not know how to swim, or have exhausted their strength, are not physically fit to escape from the back stream, float themselves in the stream. When the backflow is off, try to swim parallel to the shore, or signal for rescue or nearby residents rescues.
* The article uses references from the sources: Art of Manliness, How Stuff Work, Wikipedia …
