It’s not just the water you see that can prove deadly. It’s what lies upstream and under the surface that can really get you in trouble.

Flash floods and low-water crossings are the state’s deadliest combination, killing more people every year than any other weather event.

One local woman found herself held captive in the crossing at Bull Creek in Northwest Austin, where she learned first-hand how seemingly shallow water can sweep a car off a bridge in no time.

An important lesson - but one that nearly cost her life.

Bull Creek is normally a sleepy waterway that winds it’s way through Northwest Austin. But rains upstream can turn this sleepy creek into a rushing river in a flash.

"I just started positioning myself and just holding on for dear life," said Elaine Maxety.

She tried to drive over one of Austin’s more than 300 bridges and low water crossings, but the force of the water was too strong.

Austin-Travis County EMS rescuer Kenneth Larsen says Maxety is one of many who have underestimated the danger of low-water crossings during rain.

In the last five years, public-safety crews have rescued hundreds of people stranded in low-water crossings.

"When it becomes a battle of man versus nature, nature’s going to win every time," said Larsen.

A trickling stream can turn into a raging river...even if it’s not raining where you are.

"If the rain’s falling upstream in the watershed," Larsen said, "the rise of that water can happen so rapidly that you don’t notice it until it’s too late."

Then there’s the sheer force of the water: Six inches is enough to float a car. Twenty feet is enough to wash away any kind of car, even a pick-up or SUV.

And there are hidden dangers underneath. Moving water can damage roadways and even wash them away completely. But you’ll never know if water’s covering the crossing - especially at night.

And if you do get stranded, there’s no guarantee rescuers will be able to save you. Sometimes the swift-moving water is too much for them to navigate. In fact, more people die in flash floods than in any other type of weather event in Texas.

But Maxety was fortunate that night. Rescuers were able to park their fire truck in the water and send a brave rescuer out on its ladder. He extended his hand toward her. And that hand saved her life.

"I don’t think I’ve ever felt that desire and will to live that I felt at that moment," Maxety said.

And here’s a tip if you think that driving around a blocked-off crossing is an option. According to Larsen: "If you’re caught driving around the barricade, you stand the chance of being arrested, having your vehicle impounded, and being assessed a fine up to two thousand dollars."

Best to do what the experts say: Turn around, and don’t drown.

Low-water facts from the City of Austin website:

· Hidden Dangers- Fast-moving water causes major damage to roads and bridges. A road may look normal, but the pavement or support structures underneath may be missing.

· Hydroplaning- Attempting to drive too quickly across a low water crossing may cause the vehicle to lose contact with the road surface.

· Low Visibility- Heavy rains can reduce visibility to zero. Many flash floods occur at night making it hard to see the danger.

· The Power of Water- The strength of flash flood waters is the most deceiving element for drivers. Moving water has tremendous power to float and push anything in its path. Seemingly shallow water can tumble even large vehicles off the road.

From Interview w/ Capt. Ken Larsen, Austin-Travis County EMS:

· Rivers can rise quickly, even if it’s not raining where you are

· Six inches of water can float a car

· 20 inches of water can sweep any kind of car (including a pick-up or SUV) away

· Moving water can sweep away the road beneath low water crossings without you ever knowing it

· The human eye doesn’t determine distance well at night which makes it hard to figure out how fast the water is running and how deep it is

· If you car stalls and you can do so safely, get out of your car, and walk back the way you came to escape

· If your can’t get back to dry land safely, call 911 immediately and give them a very specific location and description of your vehicle

· More people die in flash floods than in any other type of weather event in Texas

· And for all those truck lovers out there who think their pick-ups can drive through anything, this is what Captain Larsen says: "Many of the larger vehicles, while they sit higher off the ground, also tend to have larger tires. And, the physics are simple; the larger the surface area presented to the current, the greater the force that’s applied to the object. So a large vehicle tire presents a very large surface area, and water moving at six or twelve miles an hour is enough to displace that vehicle [even a big one] from the roadway."

· If the water across the roadway is greater than 1 foot deep, do not attempt to wade across.

· If you find yourself swept into the flood waters IMMEDIATELY assume the defensive swim position – feet up, on your back, looking downstream for hazards.

Two other things to remember when going over low water crossings: · Driving too quickly through water — even shallow water — can cause you to hydroplane and possibly skid off the bridge.

· And if you’re driving at night, remember the human eye doesn’t determine distance well after dark - which makes it hard to gauge how fast and deep water really is.

Water moving at 3 mph exerts about 17 pounds of force against your legs. While one would expect the force to double as the speed of the water doubles, what actually happens is that the pressure against the surface of your legs QUADRUPLES.

The force of the water against an object is directly related to the amount of surface area in contact with the moving water.

Speed of water = Force exerted against legs, full body and canoe or boat: 3 mph = 17 pounds against legs; 34 pounds against full body; 168 pounds against a canoe or boat

6 mph = 68 pounds against legs; 134 pounds against full body; 672 pounds against a canoe or boat

9 mph = 151 pounds against legs; 302 pounds against full body; 1512 pounds against a canoe or boat

12 mph = 269 pounds against legs; 538 pounds against full body; 2688 pounds against a canoe or boat.