CABIN JOHN, Md. (WULA) -- Swift water rescue crews used a helicopter, a boat and ropes to rescue motorists trapped when a 66-inch water main ruptured just before 8 a.m., sending a four-foot wall of water down River Road near Fenway Drive.

Sharon Schoem was driving when she saw a "huge, massive wave just coming right over me." She tried to turn her vehicle around but it was too late. Caught in the current, her car began to spin around. She couldn't believe what happened in a just a matter of seconds.

"The road was fine and then all of the sudden, just a gush of water came along with boulders and parts of trees," Schoem recalled. "I tried to turn to get out of it and -- that was it. I couldn't. My car just got blocked in and the water was going over the top of the car. And the fire department finally came and got me out."

The ruptured main was spewing two million gallons of a water a minute. The high dirt banks on the sides of the River Road funneled the torrent into a wall of gushing water.

"Water was going over my car, and I was actually scared that water will draw us away somewhere because it was very strong water," added another stranded motorist, Maria Stosse.

Eight vehicles and 12 people were trapped in the water, according to Montgomery County (web | news) Fire and Rescue spokesman Pete Piringer and a Maryland State Police spokesperson. A Maryland State Police helicopter rescued three people by lifting them from their cars using baskets. The swift-water rescue team saved five people; four other motorists were able to get out on their own, Piringer said.

At least five people were taken to the hospital after suffering the symptoms of hypothermia, Piringer said. All were in serious condition, but were expected to survive.

Fortunately for those who were trapped, Montgomery County's Swift Water Rescue team, among the nation's best, is headquartered just a few yards away. Montgomery County crews were aided by Maryland State Police and U.S. Park Police.

Rescuers split into at least three teams, reaching the stranded drivers by boat, by helicopter and on foot.

Lt. Pat Mitchell of Montgomery County's Swift Water rescue team waded into the torrent with a boat, trying to get to two women trapped in two separate vehicles. With safety lines on both sides of the river to steady the craft, Lt. Mitchell fought against the raging water that threatened to throw him overboard. He called it one of the most physically demanding things he ever had to do.

"This is extremely dangerous, extremely challenging," Robert Katz, a member of the rescue team, added. "And not just from the speed of the water, but how cold it is. It decreases people's dexterity in the water. Also the number of hazards: the asphalt was literally breaking away underneath as they were moving around in the boats."

Eventually, Lt. Mitchell reached the two woman who were closest to the water main break.

"One of them was very scared," Lt. Mitchell recalled. "The first lady was very scared. But she did have a life vest on that someone had thrown her before I got here. She didn't say a whole lot, again she was scared. She followed directions to a 'T' and I thank her for that. She got in the boat and laid down like I asked her to, and the same with the second one."

Rescuers had to contend with fast-moving water, cold and chunks of debris dislodged by the torrent. The roadway was coming apart under their feet. Officials decided they couldn't wait for the water to subside; they had to act.

"Staying in the car was extremely hazardous, with the speed of the water, the volume of the water, the cars were moving and could have moved even more and if they rolled over, drowning could have occurred," Montgomery County Fire and Rescue Capt. Frank Doyle said. "This is the most hazardous event that station ten has seen in my career, has responded to on this river."

Fire Lt. Bill Phelps was in a fire engine on the way to the store when they just happened upon the incident. After calling it in, the firefighters began working on coordinating a rescue from the ground. They backed the fire engine up River Road until they reached two vehicles. The vehicle was too big to be swept away. Crews used it as an anchor to rescue the people.

"It was definitely a trying rescue for all of us," Phelps said. "The water was very cold. It was running very swiftly and the footing was treacherous."

The firefighter train all year for dealing with situtations like the one they faced Tuesday, that includes dealing with stressed out victims.

"The people were a little panicked. We calmed them down as best we could," Lt. Phelps said.

One woman who was rescued from her stranded car expressed gratitude to her rescuer, Lt. Mitchell.

"They did a good job. I'm thankful," she said.

The woman told ABC 7/NewsChannel 8 she was worried the water would wash her away.

Washington Suburban Sanitary Commission spent hours trying to close the three valves needed to shut off water to the 66-inch main. There was trouble accessing at least one of the valves.

"This is an extraordinary situation," WSSC spokeswoman Lyn Riggins said. "Shutting the water down is not always a simple process. These are huge valves. It takes about 400 cranks to shut each valve, so it's not something that can happen in a matter of minutes. It's something that took a couple of hours this morning."

Riggins said it could be several hours before the main is repaired. WSSC did not have an exact number of people who lost service; initially a spokesman estimated it would be about 100.

Montgomery County public schools closed two and a half hours early Tuesday because of the rupture. Some hospitals said they had to cancel surgeries because of a lack of water.