WARRENS, Wis. — Trying to walk in bulky waders feels wobbly enough. Add the challenge of moving through a flooded marsh without snagging a boot on a mat of underwater vines, and there's a real risk of pitching forward face-first.

But the reward is a glorious visual feast, a thick sea of candy-red cranberries that undulates with each clumsy step. It's harvest season in Wisconsin, and a chance to witness one of the Midwest's more eye-popping autumn activities.

Roughly 20 counties in Wisconsin grow cranberries with most clustered around Warrens and Wisconsin Rapids southeast of Eau Claire, with some between Manitowish Waters and Eagle River in the state's northeast corner.

Wisconsin State Cranberry Growers estimate the 2014 harvest will be close to 5.4 million barrels, which is more than half of America's harvest and more than twice as much as Massachusetts, the second-largest cranberry-producing state.

While Wisconsin easily ranks No. 1 for the tart fruit synonymous with Thanksgiving, cranberries often get overlooked in a state where cheese, brats and beer typically take top billing. This weekend, though, the tiny town of Warrens (pop. 400) welcomes more than 160,000 visitors who come for the world's biggest cranberry festival.

Take a 2½-hour road trip southeast of the Twin Cities, and you'll probably spot fruit growers along most of Warren's rural roads. The farms nurture large rectangular beds that take advantage of sandy, acidic soils left behind by ancient Glacial Lake Wisconsin. Another necessity — a landscape rich with water through ponds, streams and marshes — also enhances an autumn drive with reflections of fall colors and by drawing waterfowl that gather and prepare to migrate.

A sandhill crane calls across a pond just outside Warrens, then lifts off in the early morning light, leaving behind a group of Canada geese floating across placid water. Early European settlers, who learned about the native berry from American Indians, named the fruit craneberries because spring's tiny pink blossoms looked like the nodding head of a crane. Somewhere along the way, it was shortened to cranberry.

Public activities

The Wisconsin Cranberry Discovery Center in Warrens makes a wise first stop, offering a history of the plant, descriptions of how it grows, insight into the state's cranberry harvests (which go back to the 1830s), and a look at how cranberry consumption has expanded far beyond the Thanksgiving table and famously tart juice — especially since dried sweetened cranberries hit the shelves a few decades ago.

The center's upstairs shelves tout cranberry-everything — chocolates, honey, wine, jellies, muffin mixes and even cranberry-colored glassware, and staffers will scoop up variations of cranberry ice cream and cranberry-flavored coffee in the small cafe.

Visitors who come for Cranberry Festival must weigh even more choices, with cranberry cream puffs, cranberry chiffon pie, and cranberries jubilee cooked in a 4½-foot fry pan for sundaes.

Local marsh tours run this Friday and Saturday during Cranberry Fest, and the Wetherby Cranberry Co. welcomes visitors Oct. 4 for an annual Public Harvest Day. Besides a chance to see the marshes during harvest, the Wetherby event gives families the opportunity to don waders and head into cranberry beds to pose for photos.

"Our whole lives revolve around cranberries," says Wetherby owner Nodji VanWychen, who hopes a fifth generation takes over the operation. "Cranberries get into your blood, and you can't leave the area."

Intentionally underwater

The region's harvest season begins by late September with flooding of the beds and submerging the low-growing vines with evergreen-like leaves so custom-built machines can loosen the berries with paddles. Cranberries bobble to the surface, swirling and clustering into constantly changing formations like a ruby-red Rorschach test.

A large yellow boom corrals cranberries into a solid mass of red and tugs them toward harvesters that pull them into a chute where they tumble and bounce into a truck.

For me and other visitors wading into a marsh, we can't resist swishing our hands into cold water dense with cranberries, marveling at the sensation and scooping up big glistening handfuls. Then the urge is irresistible, and we fling them up into the air. They gently rain down in flashes of red against an all-blue September sky, forever changing how we think of fall color.

Lisa Meyers McClintick is the author of "Day Trips From the Twin Cities." Find her at www.10000Likes.com.