People in North Dakota insist that the land is so flat, they can spot an anthill a half mile away. Local lore says that when it snows at night, by morning the wind has blown it all into South Dakota. But there was too much snow to blow away this year--74.6 inches of it, the fourth heaviest snowfall on record. Then the spring thaw, usually welcome, came rushing in too fast, and on April 19, when the melting waters breached the dam and roared over the makeshift dikes, at a record 22 feet above flood stage, they created an instant Dead Sea filled with floating furniture, automobiles and thousands of memories. The vast flooding destroyed so many homes that …