DESPERATE RACE FOR SURVIVAL / RIDING FOR THEIR LIVES: Two water safety patrollers on Jet Skis at Maverick's reef turned around to see deadly 100-foot waves crashing toward them. They had just seconds to figure out how to stay alive.

jetski_107_mac.jpg Alladio and Cahill on the edge of the Pillar Point where the surfing competition takes place. Jonathan Cahill and Shawn Alladio, run jet skis during the Marericks Surf Competition, off Pillar Point each year. They were riding jet skis towing surfers out to the break back in 2001 when a 100 foot wave came straight towards them. Unable to outrun the wave they decided to go up and over the hugh swell . Photographed in, San Francisco, Ca, on 1/30/07. Photo by: Michael Macor/ San Francisco Chronicle Mandatory credit for Photographer and San Francisco Chronicle / Magazines Out less jetski_107_mac.jpg Alladio and Cahill on the edge of the Pillar Point where the surfing competition takes place. Jonathan Cahill and Shawn Alladio, run jet skis during the Marericks Surf Competition, off Pillar ... more Photo: Michael Macor Photo: Michael Macor Image 1 of / 4 Caption Close DESPERATE RACE FOR SURVIVAL / RIDING FOR THEIR LIVES: Two water safety patrollers on Jet Skis at Maverick's reef turned around to see deadly 100-foot waves crashing toward them. They had just seconds to figure out how to stay alive. 1 / 4 Back to Gallery

The waves crashing into Maverick's reef towered twice as tall as they typically do at the annual surf contest there. Many of the world's top surfers had been driven from the sea, leaving safety patrollers Shawn Alladio and Jonathan "JC" Cahill alone on their Jet Skis on the roiling waters.

It was Nov. 21, 2001, a day that would become known as One-Hundred-Foot Wednesday in the lore of Maverick's wave-riders -- who now await the call for this year's event.

As monstrous sets of waves loomed, Alladio and Cahill were forced to make a life-or-death choice in a matter of seconds: Should they try to run from the onrushing mountains of water or charge at them, trusting their skills, instincts and machines to surmount the challenge?

"That first wave was so huge, it was appalling," Alladio, a veteran watercraft racer and mother, recalled. "To the north I could see this huge hole of the barrel, like a tunnel in a cliff, sweeping down on us, roaring like a jet engine. I could see JC out of the corner of my left eye, and I remember thinking: 'I've got to survive, for my daughter. And he can't die; how could I ever explain that to his parents? So Jonathan, we can't make a mistake!' "

In midwinter, the North Pacific can be a vast cauldron of swirling winds and colliding seas, and the big-wave surfers obsessively scrutinize satellite data and buoy reports as organizers of the Maverick's Surf Contest look for the most predictable series of big waves to stage the event.

On that fabled Wednesday five years ago, two dozen surfers got all they could ask for -- and much more -- as the swells rising off the San Mateo County coast soared off the charts of the known.

Waves that thundered against the cliffs of Pillar Point at the north end of Half Moon Bay steadily increased in thickness, height and power, shaking the ground and filling the sky with spume. First, the paddle-in surfers got their fill and left the water. Then the waves got too big and winds too troublesome even for tow-in surfers, who have partners on personal watercraft to boost them onto the largest rideable swells.

By early afternoon, the only ones left on the violent sea were Cahill, 19, a surfer and natural athlete from San Mateo, and his mentor, Alladio, 40, of Santa Barbara. Cahill had helped Alladio provide safety patrols at Maverick's the previous week and she had asked him to come out again that morning.

The pair idled their craft by the "green can" buoy about a quarter-mile to sea and hundreds of yards south of the spot where world-class waves wall up to provide expert surfers with some of the world's most thrilling rides. Since dawn, Alladio had pulled from the water a half-dozen hapless spectators who had been rinsed off jetties by the rising swell. By late morning, Cahill had joined her, retrieving boards for surfers who had snapped their leashes amid the tumult.

At about 2:30 p.m., with the ocean bare of surfers, the water seethed with bubbles after the last set of waves -- with 60- to 80-foot-high faces -- had thundered through. Alladio and Cahill were fatigued and considering heading in.

Looking north toward Devil's Slide, they saw a smooth, gray line resembling a fog bank hurtling toward them at an incredible rate of speed.

"What is that?" they asked each other.

Alladio saw a faint feathering of white along the top of the ridge. It could only be storm winds ripping spray off a gigantic mountain of moving water. Cahill saw it, too.

"It's a wave!" they shouted.

It filled the horizon. They knew this monster would begin to unload its power much farther out to sea than any wave had broken so far -- and they had to decide instantly what to do.

The broad swath of aerated water that existed between them and shore could bog down their machines. A Jet Ski can't run on bubbles; it needs to pump solid water to move. Even if they turned and fled at top speed, there was no guarantee they could outrun this wave or that it would not catch them and gobble them into its hydraulic maw.

If caught, they might be dribbled off the rocky bottom, be torn apart by surging tons of seawater or be held down within roiling foam with no chance to breathe.

Alladio pointed her rig out to sea, at the onrushing wave. She looked at Cahill and screamed, "Go! Go! Go!"

They cranked their watercraft throttles wide open. Their only chance to live meant going much farther out to sea within seconds and getting up and over the moving mountain before it crashed down upon them.

Promising start

Long before the sun had even risen that day, Maverick's fans had known in advance that the wave sets would go huge.

"There already was a large, existing swell in the water," recalled Mark Sponsler, the marine weather guru who routinely assists Maverick's pioneer Jeff Clark in selecting the contest day. "Adding to that was another storm, only about 1,200 miles offshore. You had 60-knot winds pumping a lot more juice into those waves. It was incredibly strong, raw energy. That's the best way to describe it."

That morning, Sponsler, Clark and two dozen other Maverick's habitues were out early for rides, including Brazilian big-wave buff Carlos Burle and his partner Eraldo Gueiros.

"It came up like a machine," Sponsler said. "Around 9 or 10 o'clock, a 10- to 15-foot-high wave set swept through. Ten minutes later, a 17-foot set showed up. Then an 18-foot set. It just kept staircasing like that, up and up."

"At Maverick's, even when height becomes hard to measure, you can get a sense of how powerful the waves are by how far the lip throws out as it breaks," regular Maverick's surfer Grant Washburn said. "That morning, you could feel the swell getting thicker and heavier under you. The lip started throwing further and further until it was landing 50 or 60 feet out in front of the wave face. So the barrels (tubes) of the waves weren't shaped like cylinders anymore. They were shaped more like a horseshoe, lying on its side. Pretty scary!"

Washburn watched the riding zone move farther out to sea as the swell rose, and the surfers switched from paddling onto waves with their hands to being towed. By 11 a.m., a south wind rose, putting a chop in the water that made the tall wave faces lumpy and harder to ride safely. One surfer had a nasty wipeout and was pushed through the reef.

"I saw Eraldo tow Carlos into the last wave ridden on that day," Washburn said. "It was very close to an 80-foot face, one of the biggest waves I've ever seen ridden. And it wasn't a smooth face; I could see him bouncing and catching air, and I thought, 'Omigod, he might die.' But he made it all the way across. There was a picture taken just before the end, and it measured out at 68 feet high at that point. Carlos still got smashed at the end of his ride.

"After that, we all decided to go in."

The surfers safely on shore, Cahill and Alladio were alone in the water, about a mile out, as an aquatic mountain rumbled toward them.

Delicate dance

"We were cranked up to top speed," Cahill said. "Normally, that would be 65 mph on those machines, but we were bouncing off the chop so much we were probably only going about 50. We were zigging and zagging together, about 25 feet apart, trying to locate a channel of deeper water where the wave might hold up a little longer."

At that moment, as they charged up the looming wave together, Alladio thought about her daughter and glanced at Cahill -- not that she could have done anything to help him if he wasn't keeping pace with her.

"Hitting that wave face felt exactly like hitting a steep hill climb on a motocross bike," Cahill said. "But the wave itself was moving so fast, it seemed like we were being thrown backward at the same time we were going up and up. The key was to let off on the throttle at the top. Otherwise you could overshoot right off the back of the wave and fall too far, land with too much impact way out in the next trough. You had to think about not landing nose down, or tail down, but just right."

"We free-fell for about 50 feet before we landed on the back slope of the wave," Alladio said. "And those machines weigh about 900 pounds, so I went deep, down into the water almost up to my elbows. And that was the moment when I felt a little shot of panic."

They bobbed back up to the surface astride their machines. Remarkably, both engines were still running.

But in their brief view high up on the crest, they saw they were dealing with not one rogue wave but a set of huge swells. And the next one was even larger. Their desperate exercise began all over again, zigging and zagging on a parallel course, trying to keep near each other while finding a place they could make it over the top before the lip could pitch over their heads and swallow them.

They made it over that one and landed more handily, having learned throttle timing on the first. Then the next and the next in a series of at least five waves and perhaps seven. They were running on pure adrenaline and instinct and had lost count.

The ordeal -- from the first to the last wave -- lasted less than three minutes.

"Normally, when you go over a big wave, you get pelted with the spray, like raindrops, on the other side," Alladio said. "But these clots of water were huge, the size of your fist, and they exploded like you were getting pounded by water balloons. And on the wave fronts, each time we went up I could see all these fissures or ravines in the surface, and there was some kind of crazy light energy vibrating inside the wave like electricity, and I remember thinking, 'Those are the fingers of God.'

"And after we made it over the last one, we spun in circles for a moment. After that set, the whole ocean just strangely lay flat, just sort of heaving and undulating. I shut down the engine and grabbed my helmet in both hands and started to scream.

"I looked to shore, and we were so far out that the land had just disappeared. There was so much spray and foam in the air that all of Half Moon Bay looked like a snowscape, and I remember thinking, 'Hey, you could snowboard on that powder.' "

Cahill felt shocked. "I had enough adrenaline running in my body to last the rest of the week. But I knew I had just tested my skills as much as they could ever be tested, and I felt good about it. Shawn told me that we were likely the only two people in the entire world who could say they knew how everything looked after a set of waves like that."

The sea remained so aerated, Cahill said, they could barely move back to Maverick's reef above an idle pace. He kept snapping glances over his shoulder to make sure another set of waves wasn't approaching. Alladio said the water was full of bright dots of sand, the dark confetti of shredded seaweed and parts of dismembered sea creatures.

As they approached the reef, water safety patroller Paul Schulte roared up to them on his Jet Ski. "He ran around us in circles at high speed and kept yelling, 'What the f- was that?!' " Cahill said. "We later found out he had also seen that set coming and had run from the cove for the entrance of Pillar Point Harbor. He just made it inside around the jetty before it hit."

They all made it in to shore virtually unscathed. Cahill's and Alladio's ankles remained sore for weeks from the impact of their harsh landings, and Alladio later found out that some of the engine bolts on the watercraft had been sheared off. Today, they remain friends with the organizers of Maverick's but usually don't work the event.

Some doubt that the waves Alladio and Cahill surmounted did indeed reach a height of 100 feet. Wave expert Sponsler cautiously allows that "theoretically, it's possible."

Washburn says he took film footage of gigantic swells nearby later that afternoon. When he shows them to other hydrology experts now, they say the waves seem to be at least that tall.

Cahill, with five more years of experience under his belt, still thinks the second wave of that set reached between 90 and 120 feet tall. A deep ocean buoy the day before recorded seas higher than 40 feet going through at 20-second intervals that could have produced breakers of that size on the coast. And finally, a red channel buoy just south of the Maverick's impact zone was wrenched free of the ocean floor by the epic wave train and deposited on a beach 2 miles south -- an extremely rare occurrence.

"On that day, Half Moon Bay was completely closed out (huge waves were breaking everywhere), all the way down to the Ritz," Washburn says. "You can't even hype it, it was so big. But I still don't think that's as big as it can get. I wouldn't be surprised if a 150-foot wave showed up there some day."

Maverick's essentials

Calling the contestants

The sixth big-wave contest at Maverick's reef in Half Moon Bay can occur any time until March 31 on 24-hour notice. Contest founder Jeff Clark and ocean weather guru Mark Sponsler will predict that a swell of the right size and shape is on the way.

Twenty-four surfers and alternates, invited by the event organizers, will hit the water early on contest day, and a champion will be crowned. For more information about the contest, go to www.maverickssurf.com/home.

How to watch

The easiest way to watch is on the free, streaming video offered at cbs.sportsline.com or on big-screen TVs at AT&T Park in San Francisco. Spectators who drive to the contest site off Princeton-by-the-Sea will find traffic and crowd-control measures in place. Spectators also can watch the surfers from a tour boat nearby.

For more information viewing the contest, go to www.sfgate.com.

Background

There are documentary films from Powerline Productions at mavfilm.com and surf photography by Frank Quirarte at www.mavsurfer.com. A new book, "Inside Maverick's -- Portrait of a Monster Wave," by photographer Doug Acton, surfer Grant Washburn and Chronicle columnist Bruce Jenkins, is available from Chronicle Books. Jenkins' surf columns are archived at sfgate.com/sports/outdoors/surfing.

Editor's note: A correction has been made to the above story.