An Interview With Ocean Expert, Eric Lee

So many terms, so little time

While visiting Maui you’ll likely stumble upon unfamiliar weather terms related to the island—words like trade winds, swell, and visibility. In The Snorkel Store’s daily Maui Snorkel Report we often use this kind of insider language.

To clear things up a bit and to get you ready for your trip, we sat down with local ocean expert, Eric Lee, to explain the words people often use to describe Hawaii’s unique weather conditions.

Photo of Eric

Question: What are “Trade Winds?”

Eric’s Answer:

Trade Winds, yes!

Believe it or not, that word actually goes back to the European explorers in the 14th Century cruising around the globe. The Middle English word “trade” meant path or tack.

Wind moves in these specific circular patterns between the earth’s south and north poles.

The captains who understood these very specific wind patterns were able to explore the Americas for colonization and empire building.

They did end up “trading” goods with native people but that’s not where the word came from.

Question: How do “trade winds” affect us on the beach?

Eric’s Answer:

Real quick, let me go back and explain some of the science around trade winds:

Warm air (which we all know rises) approaches Hawaii from the southwest (where it’s warmer). We don’t really feel these winds as they pass because they travel above the island.

When these circular winds return to Hawaii from the northeast (where it’s cold) they smack Maui right at our shoreline! This is because cool wind travels closer to the earth.

To answer your question, Hawaii’s beaches tend to have gusty, cool winds in the afternoons. Mornings are more reliably calm on Maui.

Question: Do we have “trade winds” on mainland U.S.A?


Trade Winds miss the mainland of the U.S. completely because it’s a phenomenon that physically takes place out here the Pacific.

The entire circular journey of the wind traveling between poles happens out here in the ocean.

Question: What’s the difference between “waves”, “surf”, and “swell”?

Eric’s answer:

The most important thing to remember is that Hawaii’s swells are not generated by local weather, but by large storms elsewhere in the world. In the winter our big surf comes from storms in Alaska, Russia, and Japan.

In summer our swells come from places like Australia, New Zealand, and Tasmania.

Winter swells—or waves from far away storms—hit Maui’s north shore, and summer swells hit our southern facing shores.

Waves can be created by many different things—even wind. The east side of every Hawaiian island has waves that are caused by trade winds hitting us from the northeast. But most large waves on Hawaii are caused by weather from far away places.

Shore break refers to the waves that crash in shallow water, right onto the shoreline.

Eric in the waves

The shore break in Maui is my favorite place in the world to be. But I don’t recommend it for visitors because it can be very dangerous.

One cubic foot of water weighs approximately 64 lbs! It can knock you over in a heartbeat—or even knock you out.

Question: Why do you enjoy the shore break in Maui?

Eric’s answer:

The shore break is my ultimate “live in the moment place”.

Every wave is unique and amazing. While you’re in the shore break you have to make decisions in real time. It’s both a confidence builder and a cultivator of humility. It’s also the best view of the island, in my opinion!

Question: Is It true that Hawaii measures waves differently?

ERic’s answer:

Yes! Hawaiians measure from the back of the wave, whereas almost everywhere else measures the wave from the front.

That means you can almost double the size you hear out in Maui! If a dude says he caught a 3-foot wave surfing yesterday, that’s a 6-footer in Mexico or Australia.

Question: Do tides affect the size of waves?

eric’s answer:

Tides refer to the rise and fall of the water level in the ocean. This is caused by the gravitational pull of the sun and the moon and nothing else. The size of the waves is not caused by tides—they are simply unrelated.

Big waves aren’t caused by high tides but the “shape” of the wave is definitely affected by tides.

Surfers pay close attention to tides to find the waves with the best shapes for riding.

One more thing: There’s no such thing as a “rip tide”. When people talk about rip tides they’re talking about currents: water moving laterally in the ocean like a river.

Question: Could a strong current pull you out to sea?

Eric’s answer:

Strong currents are almost always connected to big waves. If there’s a high surf advisory you need to stay out of the ocean. When waves are big, currents could absolutely pull you out to sea in seconds.

On a calm day in Maui you don’t need to constantly worry about a current grabbing you out of the blue.

If you’re playing in the waves in Hawaii it’s important to take a peek at the currents. You can often see sand and debris moving side-to-side horizontally like it’s on a conveyor belt.

Sometimes the current moves along the shore, and other times it will move from the beach out toward the center of the ocean. This is called a rip current.

On a mellow day in Maui there’s no need be paranoid about currents. If you’re playing in big waves in Hawaii, currents will also be present and these are dangerous.

Question: Why is the water more clear some days than others in Maui?

eric’s Answer:

Underwater visibility is very important for snorkeling in Hawaii. We talk about it a lot in The Snorkel Store’s daily Maui Snorkel Report.

When water visibility is clear you get the most stunning natural views in the world. Sea turtles, tropical fish, colorful reef. When visibility is poor you sometimes can’t see you hand in front of your face.

Visibility has a bunch of different causes: temperature, current, how much salt is in the water, sunlight and rain run-off.

For example,  Molokini is famous for its water clarity because it’s made of volcanic “rock”, which doesn’t have the sand and silt that you might find at a shoreline.

Poor water visibility after a heavy rain is something that visitors to Maui should be aware of—and avoid.

When it rains in Maui, debris and waste will run from the mountains down into the ocean. This brown, murky water is dangerous and it can make you sick. The Snorkel Report will notify you when rain run-off is a factor.

Snorkeling with a turtle

There’s this idea out there that poor water visibility is dangerous because of the risk of sharks coming up and biting you.

I don’t buy this, and most folks don’t believe this is a serious concern. The real danger with underwater visibility in Maui is the risk of sickness from brown water.

Question: Are Maui’s beaches safe for snorkeling and swimming in general?


If you follow simple safety guidelines, Maui’s beaches are very safe!

Maui has more swimmable beaches than any other Hawaiian island. It also has a ton of bays—more protected from wind and waves by their half-moon geography.

View of Airport Beach

That being said, the ocean always has the potential to create a dangerous situation.

My advice: select your favorite beach based on the conditions on the island each day. There’s nothing in the world that’s better than a Maui beach day!

–>> Eric Lee is a waterman and ocean expert. Swing The Snorkel Store in Ka’anapali to get custom-fit by our amazing customer care team. Mahalo!

Eric with Kid

North view of Kapalua Coastal Trail

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