FAIRBANKS, Alaska — Even with 20 years as a whitewater rafting guide under his dry suit, Jeff “Mudflap” Estes admits he was “a little nervous” heading into the Nenana River Canyon on Saturday.

That’s what 20-foot high waves will do to even the most experienced paddler.

The 41-year-old Estes, who prefers the handle Mudflap and has been working as a whitewater rafting guide for 20 years, was one of seven guides from Nenana Raft Adventures who rafted the Nenana River through Healy Canyon last weekend at the highest water levels ever recorded on the popular whitewater river 125 mile south of Fairbanks.

“It was huge,” Estes told the Fairbanks Daily News-Miner by phone Tuesday, talking about the water conditions the paddlers faced. “There were holes big enough to eat a house.”

Why would someone want to paddle a raft through such water?

“They’re boatmen,” Nenana Raft Adventures owner John White, who has been rafting in Denali since 1986, said. “Everyone was thinking about this.”

High water

Fueled by heavy rains on the south side of the Alaska Range — the headwaters of the Nenana River actually are on the south side of the range even though the river flows north — the river was at its highest-ever volume of 35,300 cubic feet per second and a record 14.9 feet on Saturday afternoon. To put that in perspective, the normal rafting trip for tourists on the Nenana River is run at an average of 9,000 cfs and trips are canceled when it hits 18,000 to 20,000 cfs because of safety concerns. The previous record high-water event on the Nenana River was 14.4 feet on Sept. 14, 1990, which equated to about 25,000 cfs.

For a whitewater rafter, it was a dream come true.

“Oh man, it was pretty spectacular,” Estes said. “It was awesome. We got to hit it at its peak.”

The seven rafters were split up in three boats — two 16-foot catarafts rowed by lone boatmen and a 16-foot paddle raft powered by five paddlers. The more sturdy catarafts served as safety boats for the paddle boat.

The high water allowed the rafters to put in at Riley Creek inside Denali National Park and Preserve, which was a treat in itself. Normally, Riley Creek is merely a trickle and boaters put in on the Nenana River.

“Even though you only float about a half-mile in Riley Creek, just to say you went into Denali National Park and got to raft from there is pretty awesome,” Estes said.

The rafters had spent more than six hours scouting the river the day before they floated and another hour the morning of the run, so they knew what they were getting into. Even so, it still came as an eye-opener when their boats hit the water.

Shortly after merging into the Nenana River from Riley Creek, the rafters came to “Terror Corner,” which is somewhat of misnomer because it is typically a relatively placid section of the company’s wilderness, not whitewater, float.

“We came around Terror Corner and there were 20-foot swells right from the get go,” Estes said. “They were ocean-type waves. Right then we said, `It’s going to be game on for sure.”’

Connor Zwiingi, who rowed one of the catarafts through the canyon, said he could hear rocks moving in the water underneath him “like popcorn.”

“You could just feel it as soon as you dropped into the Nenana,” he said. “You could feel the force.”

Big and gnarly

Whitewater rapids are rated on a class system from I to VI, with I being the easiest and VI being unnavigable.

The 13-mile stretch of the river through the canyon featured six major rapids — Razorback (Class 4), Iceworm (Class 3), Two Rocks (Class 3), Cable Car (Class 3), Trainwreck (Class 4), and Coffee Grinder (Class 4).

The general consensus among guides last weekend, which ran the river was that the increase in water volume increased the class of each rapid by at least one, meaning the Nenana River would have qualified as a Class V river on water at least three rapids.

“It was huge, huge water,” said Zwiingi, of Coppell, Texas. “It’s kind of hard to grasp. I’ve never been on water above 20,000 cfs. It’s a lot of force. It was a pretty wild experience.”

Estes said the rapids were similar to what he encountered on a trip in the Grand Canyon last year at about this time.

“I did the Grand Canyon last October and it was running at 20,300 cfs,” said Estes, who has been guiding in Denali for the past three summers. “The Nenana looked like the Grand Canyon did — big and gnarly.”

Two Rocks Rapid featured a 12-foot wave that spanned half the width of the river and was breaking approximately every three seconds.

“That was the biggest wave I’ve ever hit,” Zwiingi said.

At a mile long, Iceworm Rapid was the longest of the six major rapids.

“It wasn’t the hardest rapid but it was a mile long of huge, 15- to 20-foot waves,” Estes said.

Trainwreck “was absolutely enormous,” he said, with huge lateral waves coming off a sidewall.

No swimming

The biggest concern among all the rafters was falling off or out of their rafts, or “swimming,” as it is called in whitewater parlance.

“The water was literally moving over 20 mph and you didn’t want to swim,” Estes said. “If you got away from your raft, you were going downstream. That’s why we had so much safety out there.”

In addition to the two catarafts serving as safety boats, the rafters had people stationed on shore at each of the major rapids prepared to throw a rope to anyone who ended up in the water.

“We knew if we were to swim it could be very, very bad,” Wes Gentry said.

As it turned out, the five paddlers in the paddle raft went for a swim in something called the Moody Hole when the raft hit it sideways and they “melted out of the raft,” Gentry said. But it wasn’t as dramatic as it could have been. None of the five paddlers were swept downstream and they were all able to quickly get back in the boat.

“We all ended up swimming but we all ended up in the boat,” Gentry said. “It was a good cleanup on the swim.”

Gentry, who is from Georgia and has been guiding whitewater trips in Denali Park for 15 years, said he has run other rivers at flood stage that were scarier than the Nenana, including some rivers in Georgia when Hurricane Katrina hit in 2005, but Saturday’s run “was the most exciting time I’ve ever had on the Nenana.”

According to the National Weather Service’s Advanced Hydrologic Prediction Service website, the Nenana River hit 14.9 feet in Healy at 1 p.m. on Saturday. The rafters finished their run at 1:05 p.m., which means they floated the river at its absolute highest.

“These guys nailed it,” said White, who watched from shore and served as a safety valve. “They floated it at the absolute peak of the flood.”

Some rafters from another guide company were talking about making the run through the canyon but ended up backing out at the last minute, Estes said.

“I’m glad we pulled the trigger and went out,” he said. “It was an epic, epic trip.”