Round after round of vicious storms are battering thousands of acres of farmland, sweeping cattle out of the fields and sending communities across Minnesota scrambling for sandbags as they brace for even more rain.

"This is one for the ages," said Fraser Norton, executive director of the Farm Service Agency in Rock County, where almost half the county's farmland was damaged by the storms that swept through the state this week. The forecast calls for even more rain before Minnesota may finally get a break Friday.

Rock County officials estimate that rain and pounding hail may have taken out 100,000 acres across the county as storms sluiced across the hills, eroding fields and sending creeks and rivers surging over their banks. Farmers are reporting that their beef cattle were washed out of the fields and drowned by the raging Rock River.

With floodwaters still blocking roads and swamping fields, it has been difficult to tally the damage to Minnesota's agricultural heartland. But it's not looking good.

"Six inches of rain in the last 36 hours is too much," said Dan Erickson, who grows about 1,400 acres of corn and soybeans with his father near Albert Lea. "But there are areas that have gotten even more than I have."

His low-lying fields are underwater, and Erickson is waiting to see how quickly the water will drain away. Corn might be able to survive if it's submerged for a day but not much beyond that.

"We need to give it a week or so to see where we stand," he said.

Minnesota Corn Growers spokesman Adam Czech is hearing reports of crop damage across southern Minnesota.

"It seems that southwestern Minnesota is the worst as far as ponding and flooding," he said, noting that western and west-central Minnesota also have saturated soils and standing water in some areas. More rain in the forecast has farmers worried, he said. The U.S. Department of Agriculture may have information next week about whether the heavy rain has affected crops.

Gov. Mark Dayton, who spent Tuesday surveying flood damage in far northern International Falls, plans to visit the southwestern communities of Luverne and Edgerton Friday.

Early estimates say almost half the 250,000 tillable acres in Rock County — 55,000 acres of corn and 45,000 acres of soybeans — have been damaged, although the full estimates will have to wait until the agronomists and crop adjusters can actually get out into the fields. And that will have to wait until the storms stop.

"The Rock River crested at two feet above its record level," Norton said. "It just keeps coming."

The rain will keep on coming, at least for the next day or so. Half a foot of water fell on Minnesota between Tuesday and Wednesday, saturating the oversaturated soil and pushing rivers and creeks over their banks. Rising water covered roads and flooded basements and devastated farmland.

"We've just gotten so much rain in the past couple of weeks that the soil's had all it can take, the wetlands are soaking up as much as they can, the streams and lakes are running high," said Craig Schmidt, service hydrologist for the National Weather Service in Minnesota. "A lot of our lakes have hit record or near-record levels. Everything's high, and there's just no place for the water to go."

In Mankato, where the Minnesota River has risen 7 feet since Sunday, officials issued flood warnings as sump pumps failed and water began seeping into basements across the city of 40,000. The city is expecting more heavy rains.

"It's just stuff," Mankato resident Melany Sutton said philosophically. She and her husband, Chase, spent Wednesday dragging their waterlogged belongings out of their flooded basement and out onto the driveway to dry while a work crew heaped their ruined belongings in a large pile. "It's getting taken care of. It's OK."

Despite the couple's best efforts — a sump pump and a backup pump — several inches of water seeped into the house from the waterlogged fields nearby. Down the street, a pond overflowed its banks and submerged part of the road and a nearby house.

In the break between storms Wednesday, damage reports rolled in from around the state. High water and mudslides closed Hwy. 66 south of Mankato, state officials reported. The Minnesota Correctional Facility in Faribault was sandbagging as rising water encroached on a prison workshop.

County Road 10 in Brown County was hit with a mudslide. Steele County residents were sandbagging around public buildings. High water closed roads in Waseca County while straight-line winds badly damaged a home in Albert Lea and the city of Maple Island lost power after a storm.

Flooding also forced the Minnesota Department of Natural Resources to close Blue Mounds State Park and Franz Jevne State Park, along with numerous campgrounds in other parks. The agency is urging Minnesotans to check the closures on the agency's website before they head out with their camping gear.

"We decided it was in the best interest of our visitors to close the park until repairs could be made and services restored," said Kathy Dummer, southern region operations manager for the Parks and Trails Division of the DNR.

Blue Mounds has seen more than 11 inches of rain since Saturday. Rising water and flood debris damaged large swaths of the park, including trails and the bison fence, although the park's herd of 90 bison have weathered the storm and remain in good health.

Meanwhile, rivers are still rising in many parts of the state.

"We're still looking for another couple of inches over the next 36 to 48 hours," the National Weather Service's Schmidt said. "And with that, I think we'll see some of the main stem rivers at least reach minor flood stage on the Minnesota and Mississippi."

Minor flood stage usually spells minor flooding around the lowlands along the riverbanks, creeping onto nearby roads and parkland. But rising water could start to encroach on major roads closer to the weekend.

Storms are expected to batter the state through Thursday, when a cool front could spell the end of the heavy storm bands, Schmidt said.

Staff writer Paul Walsh contributed to this report. jennifer.brooks@startribune.com 612-673-4482 meersman@startribune.com 612-673-7388