Thunderheads like black anvils filled the valley of the Root River, and lightning flashed like fire from a forge. It began to rain in the way that gave rise to the saying "the heavens opened." We could barely hear one another for the sound of rain crashing on the car. Sheets of water rolling off the windshield reduced my visibility to zero.

My wife and I and several friends planned to bicycle the Bluffland Trail through southeastern Minnesota, one of the region's many rail-to-trail projects. We would start in the town of Harmony, perched on the uplands above the Root, then drop into the valley and follow an old rail grade to the town of Lanesboro -- in all, a trip of barely more than 22 miles. And the next day? Who knew? Perhaps another 18 miles to Rushford or 31 miles to Houston. Either option seemed manageable, giving us plenty of time to explore and simply to hang out in Lanesboro, a gem of small-town Minnesota.

A deluge of biblical proportions is never a good thing on a bike trip. But by the time we pulled into Harmony, the rain had all but stopped. (The tornado and flash flood warnings would come later.) So, it was a go. We had our window of opportunity. We saddled up our bikes and rode out.

From Harmony, the trail roller-coastered over the surrounding farmland, bending and twisting on a course that generally led downhill toward the town of Preston. It rained enough to get wet -- and a couple of us took nasty slides on the wet wooden bridges over small creeks. But it was warm enough to be comfortable. It was fun, in fact, to cruise through farm country at bicycle speed -- past the newly planted fields of corn, the brightly painted barns and houses. As the trail reached lower and lower into the valley, we followed the course of Camp Creek. Finally, we arrived in the tidy downtown of Preston, beneath flags waving brightly against the backdrop of a freshly painted grain elevator. The subs at the Sweet Stop and Sandwich Shoppe in town hit the spot. The trail exited Preston along the course of the South Branch of the Root. Dame's rocket and Canada mayflower bloomed purple and white along the trail. Limestone outcrops erupted from the hillside next to us.

"This is just so charming!" Lee-Hoon Benson exclaimed. Indeed it was -- the profusion of flowers, the gray weather, the bucolic landscape, the flight down the cool green tunnel of the trail, the gliding stream and burbling tributaries. It exuded not only nature, but a kind of all-American wholesomeness. As we flew down the trail, we passed a man and his two kids along the stream. They had parked their bikes, and the man held a fishing rod, a silver spoon dangling from the line. "Yeah!" shouted one kid, about 3, in anticipation, "I want to go fishing, papa!"

Yes, it was charming. In fact, it was nearly perfect.

Then came the tornadoes. Later that afternoon, the owner of our campground on the outskirts of Lanesboro motored up on his ATV and suggested we take shelter at the community center. Perhaps a hundred people gathered in the rain. As we waited for the authorities to unlock the doors, we eyed the black clouds massing to the west. Then came the news of flash floods. Since our tents stood only a few feet from the Root River, we opted to brave the tornadoes to avoid the flood. We drove back out to the campground to strike our tents and pack gear in what had by then become a hailstorm.

•••

The next morning, the deluge gave way to steady rain, which turned to intermittent showers. After breakfast, the rain stopped altogether, and people began to roam the sidewalks.

Nestled in the hills and hollows of the river valley, Lanesboro, like many small towns in southern Minnesota, sprang up during the 1870s and '80s around a dam and grain mill. A railroad built along the river hauled flour to market. A steam "pusher" aided the heavy freights up the big hill west of town -- the very hill that cyclists coast down so enjoyably today. But as mills grew bigger and more efficient, operations centralized in places like Minneapolis, and little mill towns like Lanesboro slowly died.

The railroad through town had always been an iffy proposition, expensive to maintain and operate through the hilly bluff country. The Southern Minnesota Railroad Co. went bankrupt in 1871. Chicago, Milwaukee and St. Paul Railway purchased the line in 1880. With the long stagnation of business in the valley, the Milwaukee Road abandoned the line in 1979.

The same thing was happening across much of the country. Railroads were operating in bankruptcy and abandoning lines willy-nilly. Government agencies and private groups were working to put abandoned rail lines to good use as recreational trails while preserving the option of using them again someday for transportation. Even though in the Root River Valley, as elsewhere, local businessmen (who hoped the railroads would spring back to life) and farmers (who didn't cotton to an influx of strangers) opposed the effort, the old rail grade was converted to a crushed gravel trail.

As we wandered the main street of town, I found Karen Flattum behind the desk in the Lanesboro Historical Museum. She grew up on a nearby farm, she said, and from 1979 to 1983 she and her husband ran a furniture store in town. Not great timing. "That's when the town was really, really quiet," she said. "It was really tough."

But the combination of long quiescence and development of the trail turned out to be a perfect storm of good fortune for the little river town. In the doldrums for so long, the town preserved its old buildings and historic facades simply because no one had the interest or cash to change them. So when people began to visit the trail, there were plenty of old buildings to convert to shops and restaurants.

"Now there are a lot of people in town with the trail," Flattum said.

"Is that what made the difference?"

"Absolutely," she answered. "When they paved it, it really took hold."

That was in 1999. Now restored century-old homes line the streets. Gift shops, restaurants and bars line Parkway Avenue in the heart of town. Businesses advertise Amish tours. The Commonweal Theatre stages plays from "Peer Gynt" to "Man of La Mancha." And wherever you look, you see bikes for rent. And, weather-permitting, people riding.

By late morning, the sunshine, at first timid and tenuous, grew too bold to ignore. Another window of opportunity. We unloaded bikes and headed east down the trail. Alongside, the swollen river carried the soil of untold acres of farm fields in the Root Valley, and even the trunks and fully leafed-out branches of mighty trees, swept along at -- we clocked it --12 miles an hour. Soon we arrived in Whalen, a little river village with the self-proclaimed "world's best pies" at the Aroma Pie Shop. And they might have been, for that matter, although we didn't dawdle for second helpings. By the time we sped back into Lanesboro, the rain had just begun.

Greg Breining is a freelance writer in St. Paul.