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| Courtesy of Katie Thomas |
During the summer everyone enjoys a
day or a vacation at the beach, but do you really know about all the different
weather and natural phenomena taking place in front of your sunglass covered
eyes? Looking out at that large ocean in front of you while sitting on the
beach, you may not realize all the wonders that are present where the ocean and
shore meet. Phenomena like land and sea breezes, tides, wave activity and rip
currents can produce a very interesting day at the beach.
Land and sea breezes are the
patterns that describe wind movement between the sea and land. Wind breezes form because variances in temperatures cause a difference in barometric pressure, which leads to air/wind moving from a
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| Source: NCSU |
Another driving force of dynamic weather at the beach is the ocean itself. The ocean is a large “sink” that absorbs a lot of the sun’s radiation from the earth’s atmosphere. Currents within the ocean help distribute warmer and colder water to respective areas. This helps regulate temperatures in different regions of the Earth. For example, the region around the equator absorbs more of the sun’s energy than it releases and the polar regions release more energy than they receive. To create a global energy balance, ocean currents regulate overall temperature and climates; this also makes the weather along the coast more dynamic than weather inland. Without these ocean currents, regional temperatures would become too extreme and some areas would be uninhabitable.
Rising and ebbing tides and rip
currents are another phenomenon found at the beach. As you may already know,
there are high tides and low tides, which occur on a daily basis. Tides are so
predicable that they are printed in newspapers and weather apps with a high
degree of accuracy. You may also know
that the gravitational pull from the moon causes tides, but do you know how?
The moon’s gravitational force creates “bulges” in the ocean on opposite sides
of the planet. These bulges are created
by the moon’s gravitational force pulling water towards the moon and then away
from it; these bulges subsequently cause high and low tides. When the moon is
directly above you, you should be experiencing high tide. Then when the moon is
directly overhead on the exact opposite side of Earth, you experience a low
tide. Therefore, high and low tides are generally about 12 hours and 30 minutes
apart. Another spectacle at the beach is rip currents. Most times rip currents
can be more dangerous than anything else at the beach. Rip currents are created
when waves travel to shallower water and some waves crash harder than others at
points on the beach. This area becomes worn down as sand is pulled out to sea and
begins to give way creating a break in the sand. This break allows for water to
flow out to sea in a narrow channel at a much quicker pace than the surrounding
water returning to the ocean. The concentrated stream of water has the power to
possibly pull you out 200 yards or more. A sand bar, is a beach surface that is a few
feet above the rest of the surf line, is what normally erodes and breaks and causes fast moving water to return to the ocean. So if you see a sand bar and
rough surf, that could be where a rip current may occur. Further, an active rip current will have a
foamy and turbulent appearance as compared to the rest of the tidal activity
around it. If you find yourself caught
in a rip current, don’t fight it; allow it to pull you all the way out and then
swim parallel to the shore. Even the strongest swimmer can’t swim back to shore
amid a rip current. Most importantly, don’t panic. Understanding the aspects of
a rip current is the best way to avoid panic.
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| Courtesy of Katie Thomas |
Speaking of crashing waves, have
you ever wondered why waves break at certain points along the surf? The key to
understanding why waves break is connected to the height of the wave, the depth
of the water beneath it, the gradient or slope of the beach and the energy of
the wave. A wave starts to crash when the ocean depth decreases to half of the
wave’s wavelength. When this occurs the wave begins to touch the bottom of the
ocean floor. Water molecules begin to
scape across the ocean floor, causing drag or friction and the wave’s energy
begins to decrease, thus the wave grows upward increasing the wave height. As
the wave continues to drag along the ocean floor, friction slows the bottom of
the wave down as the top of the wave rushes ahead leaning forward until it tumbles
over and crashes on shore.
As you can now see there is so much
more occurring at the beach than you may have first thought. Weather at the
coast is very dynamic and often changing by the hour. One thing you can count
on is when to expect high and low tides. Local surf shops and apps have tide
tables for specific locations. Be sure
to check those out! Now that you know a little bit more about natural
phenomenon along the coasts, enjoy your summer vacation at the beach and as you
stand at the waters edge you will be much more aware of all the weather and
ocean activity that is happening right in front of you!
-Katie
-Katie
