The Great Lakes hit the second highest level of ice coverage in recorded history this winter.

The U.S Coast Guard allowed me to spend a couple days on the Cleveland-based ice breaker, the Morro Bay, as it began a six week mission to open tracks in the ice for cargo ships.

Lt. Kenny Pepper captains one of the U.S. Coast Guard's nine icebreakers on the Great Lakes.

"We're going to start looking at what we call spring breakout, where we start opening up waterways and establish tracks for lakers to get moving again," says Pepper.

Large cargo ships that move commerce on the Great Lakes are called lakers.

According to the National Oceanic and Atmospheric Administration over 200 million tons of cargo are shipped every year through the Great Lakes. The three main cargoes are iron ore, coal and grain.

Shipping season starts in late March, but, with current conditions, ships can't move through most areas without assistance from a breaker.

George Leshkevich with the Great Lakes Research Labratory says ice coverage peaked at 92.2 percent coverage on March 6, making it the second most ice in recorded history.

The most ice ever recorded was 94.7 percent coverage in 1979.

Thickness varies lake to lake; however, Leshkevich says official measurements of ice more than 3 feet thick were take on Lake Erie this year.

Shipping is difficult, but the ice has a positive effect on the lakes. Water levels have dropped the last couple of years. The deep freeze limits evaporation, and, when the ice melts, it will raise the water levels.

All ice is not created equal. On the day we left port from Cleveland, the ice was widespread along the shoreline.

For the most part, the Morrow Bay moved at its top speed of 15 knots periodically slowing down, even stopping, as it broke through icy barricades several feet high.

The barricades, called ridges, are formed when pressure forces ice upward.

On a working ice breaker there is no smooth sailing. Ice crushing under the hull creates a constant roar and vibrations throughout the ship.

"We say it's kind of like living inside a rock tumbler," says Pepper.

Intense vibrations, noise and sudden lurching can wear on crew members, who say it's all part of the job. There is no complaining, but the crew acknowledges the conditions can be fatiguing.

"It's mentally exhausting hearing all day," says Executive Officer Dan Swaim.

The 17-man crew on the breaker sometimes works round the clock.

It is unusual for people who are not military to spend the night on a ship.

We were given the option of spending a couple hours on the thinner ice closer to Cleveland and being dropped back off, but we requested to stay with the ship and travel out into the tougher conditions that haven't been recorded.

We hit those conditions after dark when the noise level suddenly increased and the ship slowed to a stop.

Where the hull cracked through you could see the ice was at least 20 inches thick.

The decision was made to stop and allow the crew to get a good night sleep.

Fatigue can be an issue. The cutter would have pressed on if a ship was in need assistance or if ice jams on rivers were raising the possibility of flooding.

Sunrise reveals the conditions few people will ever witness.

Mile after mile of solid ice several feet deep.

There are no ridges or cracks in the ice to relieve the pressure or allow the ice movement. The ice is solid and thick. Conditions only an icebreaker can bust through.

"At that point we do what's called backing and ramming. We just back up and ram," says the captain.

That's 660 tons of ship crashing into the ice. A specially designed hull includes what is called a bubbler. Holes in the hull blow out bubbles. The air acts as a lubricant to help the ship move through the ice, but moving forward, in this case, is measured in yards.

We witnessed the difference a breaker makes when the Morrow Bay located a track cut by the Canadian Coast Guard the day before.

The track is filled with chunks of ice but the lack of resistance allows the cutter to bring its engines back to top speed.

"Because this is such a historic event, the ice this season, everyone is looking to doing their part as an ice breaker," says Swaim.

The crew of the Morrow Bay has been anxious to get back on the water.

The breaker was in port for four weeks for scheduled maintenance and mechanical problems. Fuel injectors had been rebuilt too many times and were leaking.

The Coast Guard's Nea Bay is also based in Cleveland. The Nea experienced the same fuel injector issue, which kept both ships in port at the same time.

The Coast Guard constantly changes the location of it ships to where they are needed most and says having the two cutters temporally out of service did not leave any cargo ships stranded.

Both cutters are back on the lakes now.

The Morrow Bay was commissioned in 1981 and is scheduled to under go is what called a service life extension in July. The ship will be mostly gutted and rebuilt.

In addition to creating tracks, icebreakers also perform what's called a direct assist. Pressure from ice can trap cargo ships. Breakers circle the ship creating cracks in the ice, relieving the pressure and releasing the ship.

The breakers operate in federal waterways and are sometimes called to rivers to break up ice jams that can create flooding.

Conditions on the Great Lakes will get worse before they get better.

Right now the ice is so thick and widespread that it is held in place. When the plates starts to crack and melt, large slabs of ice will move back into the tracks.

How quickly the ice melts will depend on the weather.

The role of the U.S. Coast Guard on the Great Lakes is multi-faceted.

For more information visit their website,

To check out satellite images of this winter's ice coverage on the Great Lakes, visit: