It happens every time Nichols tells his kayaking class it's time to roll in the water with a boat attached to their waists.

"It's a major factor for a lot of people. Even pretty good swimmers have a hard time being upside down under the kayak. You can sort of feel trapped, even though you aren't," said Nichols, who has been teaching people to kayak at the University of Utah since 1979. "Usually, after a couple of weeks, people become more comfortable with it. But some do not and they move to inflatable kayaks to avoid that feeing of being stuck."

Even though she had spent years doing water ballet, Marlene Egger was among Nichols' students who had a hard time performing the roll.

"It was the scariest thing I had ever done. It was also the riskiest thing I had done at that time," said Egger, who took the class in 1981 at age 29. "Most people learn how to roll in half an hour or a couple of weeks. It took me five quarters of classes at the pool before I could do it with confidence. Now, my roll is bombproof."

A study released in 2002 by the Outdoor Industry Foundation (OIF) reported there are more than 44,500 whitewater kayakers in Utah, who typically pilot smaller boats capable of doing tricks in the water. Another 22,000 Utahns list themselves as recreational kayakers, while 44,000 say they are touring kayakers more likely to use longer, flatter boats. An OIF study released in 2004 says more than 9.9 million Americans older than 16 participate in some form of the sport.

The number of kayakers swells in high-water years, when rivers are roiling and big flows enhance existing challenges and create new ones. Utah's bountiful runoff is opening waterways that have been impassable for years due to the drought, while others are so high they are dangerous.

For a desert, Utah has numerous opportunities for kayakers. Some rivers offer year-round thrills and spills, but many are seasonal. This time of year, it's hard to find a paddler at home.

Gunther Haidenthaller, 49, was drawn to sport after watching kayakers on television competing in the Olympics during his childhood.

"They were using these really thin boats and it just looked fascinating . . . how someone could be paddling upriver. It got me thinking about how cool it would be try. It was always in the back of my mind," said Haidenthaller, who took up the sport seven years ago.

He says the thrill of kayaking is hard to explain, but revolves around hydrodynamics.

"It is just exciting to be on moving water. There is a whole freedom of being able to maneuver. I'm not sure what it is exactly, but it gets in your blood," said Haidenthaller, a self-proclaimed adrenaline junkie. "There is unique excitement with big foaming rapids and just punching through."

Larry Stewart, 51, Egger's husband and president of the 60-member Utah Whitewater Club, first tried kayaking 17 years ago.

"My wife got me into it. I used to spend most of my weekends backpacking. She has bad knees and eventually got me out of backpack and into a kayak," said Stewart.

Stewart learned the roll faster than his wife, but still doesn't like the idea of bouncing his head on boulders while sitting upside down in a boat and running Class IV rapids.

"I prefer big-water rivers because it's not the water I mind -- it's the rock I'm allergic to," he said.

Like many other outdoor adventure sports, kayaking has an image of being hard-core. While some paddlers relish that reputation, it's not always deserved.

"They say kayakers come in two categories: old and bold. I'm definitely an old kayaker. The better you get at kayaking, the more humble you become as you realize the water is big enough to really trash you," said Egger, a 52-year-old statistics, public health and health services research professor at the University of Utah. "Some people think that because I'm a kayaker I'm a risk junkie. I don't see myself that way. I'm always responsible and managing the risks."

Some things have changed dramatically since Egger, Stewart and Nichols got involved in the sport 20 years ago. The biggest difference is the boats.

"They used to be a lot longer. Most people learning to kayak back then were using them just to run rivers. They did a lot of camping and overnight trips," Nichols said. "Today the boats are a lot shorter and more people do it just for the tricks. They don't run rivers anymore; they pick a section of river and they stay there all day."

Kayakers call it "park 'n' play." It originated when slalom-style kayakers accidentally pulled some tricks while trying to maneuver quickly through river hydraulics.

"The boats are designed to help people do all these tricks," said Charlie Butler, co-owner of Wasatch Touring in Salt Lake City. "That means they are shorter, as short as they can make them and still allow people to get their legs in."

Butler said the new kayaks, sometimes called rodeo boats, were designed to be similar to wake boards. Now, he said, it's difficult to find the longer, tapered boats.

brettp@sltrib.com

Rapids classification

This is the Americanized version of the international system used to rate river difficulty. The system is not exact and the changeable nature of rivers means the danger level is also constantly changing. Kayakers always should scout rapids before making a run.

* Class I: Easy. Fast-moving water with riffles and small waves. Few obstructions, all obvious and easily avoided with little training. Risk to swimmers is slight; self-rescue is easy.

* Class II: Novice. Straightforward rapids with wide, clear channels that are evident without scouting. Occasional maneuvering may be required, but rocks and medium-sized waves are easily missed by trained paddlers. Rapids at the upper end of this difficulty range are designated "Class II+."

* Class III: Intermediate. Rapids with moderate, irregular waves that may be difficult to avoid. Often requires complex maneuvers in fast current and good boat control in tight passages or around ledges; waves or strainers may be present, but are easily avoided.

* Class IV: Advanced. Intense, powerful, but predictable rapids require precise boat handling in turbulent water. Depending on the character of the river, it may feature large, unavoidable waves and holes or constricted passages demanding fast maneuvers under pressure. A strong Eskimo roll is highly recommended.

* Class V: Expert. Extremely long, obstructed or violent rapids that expose a paddler to added risk. Drops may contain large, unavoidable waves and holes or steep, congested chutes with complex, demanding routes. Rapids may continue for long distances between pools, demanding a high level of fitness. Because of the large range of difficulty that exists beyond class IV, Class V is an open-ended, multiple-level scale designated by class 5.0, 5.1, 5.2, etc. Each level is an order of magnitude more difficult than the last.

* Class VI: Extreme and exploratory. These runs are rarely attempted and often exemplify the extremes of difficulty, unpredictability and danger. The consequences of errors are severe and rescue may be impossible. For teams of experts only, at favorable water levels, after close personal inspection and taking all precautions.

-- American Whitewater, http://americanwhitewater.org/

Learn mor about kayaking

Talk the talk

Playboating -- Performing such tricks as surfing, spinning or squirting

Surfing -- Sliding down the face of a wave so that the boat remains stationary despite the current.

Spinning -- Spinning the boat while surfing.

Stern Squirt -- Standing a kayak on its tail with the bow high in the air.

Cartwheel -- Rotating boat vertically in water so the ends are alternately in the air or under the surface.

Eddy -- Relatively calm water behind an obstruction in the river.

Pour-over -- Water flowing over a rock just under the surface, creating a vertical drop into a hole.

Ferry -- Paddling diagonally upstream to cross a river without drifting downstream.

Hole -- A type of wave where water piles on itself, forcing aerated water upstream and into the wave's trough.

Strainer -- A tree or log in the river that allows water to pass but traps people and boats.

Source: Larry Stewart, president of the Utah White Water Club

Paddlefest 2005

The Utah Rivers Council's Paddle Festival is Saturday and Sunday at Little Dell Reservoir (exit 134 off of Interstate 80). Learn how to paddle and demo kayaks, canoes and sailboats. The event includes instruction on sculling and clinics on how to roll a kayak, plus paddle races, fly-fishing instruction, children's events and live music.

Hours: Saturday, 9 a.m. to 5 p.m.; Sunday, 9 a.m. to 4 p.m. Admission, $10 for adults, $6 for children 6-12. Proceeds benefit the Utah Rivers Council. Visit http://www.paddlefestival.org for more information.

Take lessons

Kayaking has been taught at the University of Utah since 1975. Classes are offered through the Natural Resources Learning Program and include whitewater kayaking I, II and III (all in the pool), intermediate kayak on the Green or Colorado rivers and sea kayaking. Classes are open to U. students and non-students. Visit http://www.health.utah.edu/prt/nrl.htm for more

information.

Classes are also offered at Wasatch Touring in Salt Lake City (http://www.wasatchtouring. com/) and through Utah State University in Logan (http://www.usu.edu/canoe/home.html). The Utah Whitewater Club hosts a series of open pool practices where members help beginners. Visit http://www.utahwhitewaterclub.org/ for more information.