The tumbling water roars extra loud and fast each spring at the High Falls along northern Minnesota's border with Canada, its spray often shimmering into a small rainbow as the water crashes into the Pigeon River.

But relatively few people are there to see it. A busy spring day at the waterfall overlook in Grand Portage State Park brings only about half the traffic of a busy summer day, the park's manager said.

While summer and autumn are high tourism seasons in northern Minnesota, and winter is popular with skiers and snowshoers, spring is typically a tourism downer. People in the southern half of the state basking in warmer weather feel little desire for a drive north.

So for the past few years, tourism marketers in Cook County have been promoting an often-overlooked spectacle: the region's gushing waterfalls.

As the snow in Minnesota's Arrowhead melts into streams and rivers, eventually cascading into Lake Superior, locals have long been entranced by the captivating display.

"It was kind of one of those things where we were like 'Why aren't we talking about this?' This phenomenon happens every year and us locals have been enjoying it," said Kjersti Vick, marketing manager for Visit Cook County. "It was like a light bulb."

The idea has given extra life to cash registers and government coffers, too. Since launching the waterfall campaign in 2014, lodging taxes for the months of April and May have grown 31.9 percent, according to the group.

Some resorts specifically advertise specials for waterfall seekers.

Eagle Ridge Resort at Lutsen Mountains advertises a "Roaring Rivers" 50 percent off special for midweek stays.

Guests at nearby Lutsen Resort, which also offers specials, don't have to look far for gushing water: The Poplar River flows into Lake Superior right at its lakeside property. But the resort offers guided tours to other waterfalls, too.

"As soon as we quit snowshoeing and cross-country skiing ... we start offering our guests the opportunity to go out with one of our activities guides and take a look at some of the various great waterfalls and rapids," said owner Nancy Burns. "I think people are increasingly aware of the amazing rivers."

Visit Cook County made a printable map detailing the county's best 15 waterfalls, available at visitcookcounty.com/adventures/waterfalls. The map also includes a range of places to watch for seasonal "pop-up" waterfalls cascading down the hill along scenic Hwy. 61.

The organization puts out social media messages forecasting "peak" waterfall season, which is typically in mid-April and through early May, but can sometimes start in March and last into June.

This winter's cold has slowed the melt, keeping the most snow on the ground in early March since 2014. That promises some spectacular spring runoff in the counties all along the North Shore.

As for the High Falls — at 120 feet, the tallest in the state — Grand Portage State Park Manager Travis Novitsky advises visitors to wear rain gear.

During peak season, he's seen the falls flow at 46,000 gallons per second, far above the yearlong average of 3,200 gallons, he said. The spray from the falls hitting a gorge rises and swirls and showers people watching it from a platform.

"You just get inundated with it when it's at peak flow," he said.

As the Visit Cook County website says: "Hundreds of thousands of acres of melted snowfall finds its way into Lake Superior and on the way, creates quite the show."

@pamlouwagie • 612-673-7102