CURRENTS- Rivers Through The Surf
waves are formed by wind on the water. Sea waves usually result
from storms, often hundreds of miles from shore. Waves are not
all equal in size. Sometimes a group of larger waves comes ashore
one after another. This is known as a "set" of waves.
waves break, water is pushed up the slope of the shore. Gravity
pulls this water back toward the sea. If it converges in a narrow,
river-like current moving away from shore, it forms what is known
as a RIP CURRENT.
currents can be 50 feet to 50 yards or more wide. They can flow
to a point just past the breaking surf (the surfline) or hundreds
of yards offshore. Some 80% of rescues by lifeguards at America's
surf beaches are due to persons being caught in rip currents.
currents may pull continuously, but they can suddenly appear or
intensify after a set of waves, or when there is a breach in an
offshore sandbar. Longshore currents, inshore
holes, and other bottom conditions contribute to the formation
of rip currents. Inshore holes and sandbars can also greatly increase
the danger of spinal injury.
RIP CURRENT SURVIVAL
sea is a wonderful playground, but you must respect its power.
Learn to swim and consider participating in a
junior lifeguard program. When swimming, choose an area protected
by lifeguards. If you are not a strong swimmer, go no further
than knee deep. If you decide to swim, check the conditions first
to identify any dangerous currents. Ask a lifeguard for assistance.
can sometimes identify a rip current by
its foamy and choppy surface. The water in a rip current may be
dirty (from the sand being turned up by the current). The water
may be colder than the surrounding water. Waves usually do not
break as readily in a rip current as in adjacent water.
caught in a rip current, try to relax. A rip current is not an
"undertow" -- it will not pull you under. Do not try to swim against
the current as this is very difficult, even for an experienced
swimmer. If you can do so, tread water and float. Call or wave
for assistance. You can also try to swim parallel to shore until
you are out of the current, then swim directly toward shore.
same forces which cause rip currents also cause longshore currents.
These currents are most evident when waves hit the shore at an
angle. This tends to cause the water to be pushed along the beach
away from the direction of the oncoming waves. Usually, longshore
currents are less hazardous than rip currents because they move
along the shore, not away from the shore, but they can knock children
and weaker adults off their feet. More importantly, longshore
currents can feed and increase the power of rip currents. In other
words, the longshore current may move along the shore, then turn
offshore to become a rip current.
wave conditions, particularly seasonal changes in wave patterns,
can create unevenness in the ocean bottom. This includes sandbars
and sudden deep spots, called inshore holes. They can surprise
waders, who suddenly find themselves over their heads. They can
also create channels in the bottom, which concentrate and greatly
intensify the power of rip currents. At any beach with uneven
bottom conditions or obvious sandbars, a higher level of caution
should be used.
for a list of USLA safety tips. We recommend that you follow all of them to ensure maximum safety in the water.
FREE EDUCATIONAL MATERIALS
to download a free rip currents brochure and sign from the USLA website.
to access NOAA educational materials about Rip Currents.
CSLSA thanks the California State Lifeguards
and the Trauma Research and Education Foundation for their assistance
with this information.