Seth Perlman / AP

Steve Peters uses a make shift bridge to access dry land in Peoria Heights, Ill. The Illinois River crested at 29.35 feet, eclipsing a 70-year record in Peoria.

A 54-year-old Missouri woman died Wednesday after apparently being struck by lightning, as states along the Mississippi River continue to fight back flooding and farmers struggle in what has been an unrelentingly wet spring in the region.

Authorities say Connie Lou Wake was discovered by her son in the front yard of her home in the south-central part of the state. It was the first lightning fatality this year in the state, which had 28 last year.

Meanwhile, residents of towns along the Mississippi River in eastern Missouri have been spent the past several days filling and stacking sandbags to keep the river from flooding their homes and businesses. 

The mighty river crested early Thursday in St. Louis, reaching 5.5 feet above flood stage before retreating. But the river is still a day or two away from reaching its peak in areas further south in the state.

To the north, a damaged lock may keep a stretch of the Illinois River closed to commercial shipping traffic for weeks, the U.S. Army Corps of Engineers said. Flooding has halted the transport of corn and soybean barges at certain terminals on the river, Reuters reports. The disruptions could cause significant disruptions in the flow of grain and corn in the second-highest soybean producing state.

Reuters reports almost 60 percent of U.S. grain exports are transported on the Mississippi River and its tributaries. Grain prices at export terminals at the Gulf of Mexico climbed this week to the highest level in at least a month due to the disruptions.

Production has also suffered, as farmers who would normally be planting corn right now are halted because of the wet, muddy ground. Darren Walter, who farms in Grand Ridge, Ill., told the Associated Press he needs warmer weather to dry the ground in a part of the country where temperatures have continued to drop to 30 degrees at night.

And while the effects of the heavy downpours will continue to be felt for months, some areas are at least beginning to feel some relief. In North Dakota, officials announced the Red River would crest next week at lower than anticipated levels.

The river is still expected to peak at possibly its second-highest level on record, and flood preparations are being made throughout the north-central United States.

Reuters and the Associated Press contributed to this report.

Robert Ray/ AP

Water levels on the Mississippi River continue to fall near Vicksburg, Miss., seen in this Aug. 6, 2012 photo.

ABOARD THE DREDGE JADWIN IN THE MISSISSIPPI RIVER – The drought of 2012 has humbled the mighty Mississippi River.

A year after near-historic flooding, the river’s water levels are at near-historic lows from Cairo, Ill., where the Ohio River empties into it, to New Orleans, just north of its endpoint at the Gulf of Mexico.

In July, water levels in Cairo, Memphis, Tenn., and Vicksburg, Miss., dipped below those of the historic drought of 1988. That’s affecting everything from commerce on the maritime superhighway to recreation to the drinking water in Louisiana.

The biggest impact may be on shipping. “It’s getting near critical,” said Austin Golding, a third-generation co-owner of Vicksburg, Miss.-based Golding Barge Lines. “Without more rain, we’re heading into uncharted territory.”

About $180 billion worth of goods move up and down the river on barges, 500 million tons of the basic ingredients for much of the U.S. economy, according to the American Waterways Operators, a trade group. It carries 60 percent of the nation’s grain, 22 percent of the oil and gas and 20 percent of the coal, according to American Waterways Operators. It would take 60 trailer trucks to carry the cargo in just one barge, 144 18-wheeler tankers to carry the oil and gas in one petroleum barge.

The low water levels mean that barge companies have to lighten their load by about 25 percent so the barges ride higher in the water, reducing what’s known as the barges’ “draught.”

That means each tow boat is moving less cargo than usual even though “it takes up the same amount of fuel to burn and the same amount of manpower,” said Ed Henleben, senior operations manager for Ingram Barge Co. in St. Louis.

Already this summer, there are been 15 to 20 cases of barges running aground, according to Steve Jones, the Army Corps of Engineer’s Mississippi River navigation manager. Some cases have stalled river traffic for as much at three days. At this point in an average summer, there’d be only about eight or 10, Jones said.

And as the water drops, the river channel narrows. In some places, the Mississippi is a one-way river as barges heading north have to wait for traffic headed south, adding to the costly delays.

The result: Millions of dollars in higher shipping costs.

“The products we tow, that product costs more,” said Golding. “Somebody’s got to come up with that cost.”

Economists say ultimately, it will be the consumer.  “Some markets such as spot markets for agricultural products will be immediately impacted by increased transportation costs,” said Donald Sweeney of the University of Missouri-St. Louis.

The navigational hazards of the low water levels are compounded by last year’s flooding, which resulted in a great deal of soil and silt being washed into the river, altering and raising the riverbed.

Because of that sediment in a flood, “as the ceiling rises, so does the floor,” said Golding. “We’ve just dealt with a historic flood, then the water drops.… We have some 50-year guys who’ve never seen anything like this before. It’s a completely different river than anybody’s ever seen.”

As the Army Corps of Engineers’ navigation manager, Jones spend eight to 10 hours a day directing dredges to keep a navigable channel from St. Louis south at least nine feet deep (a system of locks and dams manages the water depth north of St. Louis). So far, the government has spent about $60 million in the effort.

The low water levels in the Mississippi are also resulting in a wedge of salt water creeping upriver from the Gulf of Mexico, threatening the drinking water supply in New Orleans. The Army Corps of Engineers hopes to begin work this week on a $5.8 million underwater barrier to block the saltwater’s advance.

The river’s low levels are the result of a combination of the mild winter in the Upper Midwest, which resulted in very little snow melt to feed the river, and the dry spring and summer in the tributaries to the Mississippi and Ohio rivers.

What will it take to get the Mississippi back to normal? Says Jones: “Rainfall – which will occur, it’s just a question of when.”

Slideshow: America's farmland baking in drought

Drought conditions plague much of the United States after a summer of scorching temperatures and a lack of rain. The dryness is affecting America's farmland, threatening crops like soybean and corn.

Launch slideshow

More coverage of the drought: 

‘Best year ever’ for some farmers outside drought region   

Forced to sell cattle during drought, dairy farmers ‘just keep praying’ for rain

Drought expected to take toll at checkout

Americans tell their story of #Drought2012 

In drought-stricken Wisconsin, farmers helping farmers  

Emergency well drilling brings relief to farmers stricken by drought

Have you been affected by the worst drought in more than 50 years? Share your photos with us on Instagram, Tumblr or Twitter with the tag #Drought2012. You can also upload your photos in the box below. 

Nati Harnik / AP

Dead fish lie on a sand bar at the Platte River near the Louisville State Recreation Area in Louisville, Neb., on July 17. The water level has dropped even further since then.

It's not just on land where drought is taking a toll: a 100-mile stretch of the Platte River has dried up, while barges along the lower Mississippi are having to carry less cargo in order to navigate shallower water.

The Mississippi impact is one that goes far beyond the immediate area: About 60 percent of the nation's grain, 22 percent of its oil and gas, and 20 percent of the nation's coal goes down the river. Lighter barges mean longer waits for those products.

The Army Corps of Engineers is tasked with dredging parts of the river where barges ground, and business is booming.

"We're dredging around the clock," Bob Anderson, a spokesman for the Corps' Mississippi Valley District, told NBC News.

The latest grounding happened Thursday about 10 miles south of Greenville, Miss., backing up several tows before it was cleared and traffic resumed Friday morning, Anderson said.

The situation is the opposite from last year when flooding saw the Mississippi crest at nearly 48 feet above the baseline near Memphis, Tenn.

Lately the river has been six to seven feet below the baseline -- 12 feet below normal for this time of year.

It could drop another 2.5 feet by the end of August, National Weather Service meteorologist Marlene Mickelson told Reuters, calling that a "worst-case scenario."

And while it's not as bad as the historic low of 10.7 feet below baseline, recorded in 1988, it is unusual in that it's so early in the season, Mickelson said. 

Anderson said locals are hoping rain will raise the water level by four feet or so over the next few weeks. But "if we don't get more rain" it'll then start to fall again, he added.

For the barges, every inch of water counts.

Barges must unload 17 tons of cargo for every one-inch loss of water and 204 tons for every one-foot loss of draft, Tom Allegretti, president of the American Waterways Operators, said in a recent statement. Draft is the distance between a ship's waterline and the lowest point of its keel.

"When you consider that a typical tow on the upper Mississippi or Ohio Rivers has 15 barges, a one-foot loss of draft will decrease the capacity of that tow by 3,000 tons," Allegretti said. "The tows on the lower Mississippi River are larger, consisting of 30-45 barges, resulting in decreased capacity of over 9,000 tons."

He said it would take 130 semi trucks or 570 rail cars to haul the freight unloaded by one large barge under those conditions.

Locals are doing everything in their power to manage -- and that means barges are loading less, the Coast Guard is constantly resetting buoy lines that help navigate, and the Corps is dredging.

"Right now everyone is working together to keep the river open," Anderson said. 

River conditions were even worse during the 1988 drought, when a 100-mile stretch south of Memphis was closed. At one point, more than 700 barges were backed up on the river near Greenville, Miss.

Lessons learned then prompted changes in how the Army Corps of Engineers maintains the river and, as a result, have lessened the impact of this year's drought. Those changes include new dikes and other structures that direct water in key areas.

On the Platte River, meanwhile, sand, plants and tire tracks are now the dominant features along a stretch near near Columbus, Neb.

Someone with a dry sense of humor even put up a cactus in the middle of the river, TheOmahaChannel.com reported.

"This is the worst I've ever seen it, and I've been on the river since I was a pup," Dan Kneifel, who runs Geno's Bait and Tackle Shop, told TheOmahaChannel.com.

The river is essentially dry from Columbus to Kearney, about 100 miles away.

"You may find a little trickle in some stretches of that, but nothing to support fish," Daryl Bauer, a Nebraska Game and Parks Commission staffer, told the Lincoln Journal-Star.

"The river was full of fish, and to see them all die is a travesty," said Kneifel.

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SEAN GARDNER / Reuters

Freddie Walker stacks sandbags to protect Ergon Marina along the Mississippi River in Vicksburg, Mississippi on Tuesday.

By Thanh Truong, NBC News Correspondent

VICKSBURG, Miss. – Austin Golding is the third generation in his family making a living off the Mississippi River.

Back in 1967, his grandfather founded Golding Barge Line. The company moves millions of pounds of product (mostly petroleum) up and down the river each year – but now its office in Vicksburg is surrounded by water. We met him as he gave us a lift in a boat across what used to be the office's parking lot.

"I was raised around this river, and I've never seen it this high. No one alive has seen it this high. When you're around the water this much you learn to respect the river and its power real quick," he said.

With his bright blue eyes and youthful face, the 25-year-old spoke with a tone of experience you would expect to hear coming from a river man twice his age. But he and most people in Vicksburg know the potential for flooding. The Mississippi River and Yazoo River meet in Vicksburg. The city expects to see the water rise to levels not seen since 1927.

"This is going to be an epic flood. I just pray that the infrastructure that's in place and the work that's been done will protect us," said Golding.

Scott Olson / Getty Images

Jermaine Jarrett paddles a boat down a flooded street in his neighborhood on Monday in Memphis, Tenn. Click on the photo to see a slideshow of the floods across the U.S.

There are temporary flood walls along the levees near downtown; water though is already seeping through those walls. Low-lying areas along the Yazoo River have already had roads swallowed by rising water. The worst flooding isn't expected for at least another week.

"We'll be here, we're not going anywhere. This is our life. This river has given us so much but when it comes – you just get the hell out of its way," Golding said.

Mighty Mississippi crests in Memphis