Humans can’t live without water. They also can’t live very long with too much water. A report by the UN stated that, in the last 20 years, over two billion (yes, billion) people have been affected by floods. Rescue by helicopter during flooding is a very dynamic and often unpredictable process. It is an environment that can kill otherwise healthy people quickly by hypothermia and drowning, which can severely limit the amount of time given to perform a rescue. In addition, there are a wide variety of possible scenarios with floods that demand different techniques and equipment.

Tried and tested techniques

“Our flood rescues typically take place in our monsoon season, which is late spring to summer when moist air from the south is pushed into Arizona,” stated Dan Millon, Jr, Chief Paramedic with the Arizona Department of Public Safety (AZDPS). “These tend to be flash flood events where people try to cross flooded roads in their vehicles and get stuck.”

One of the AZDPS’s basic techniques is to hover with one skid about a foot above the roof of a vehicle to remove passengers

The AZDPS has four single-engine Bell 407 helicopters that are used for flood rescue events. It also has one twin-engine Bell 429 equipped with a hoist, although it is not yet used for water rescues.

One of the AZDPS’s basic techniques is to hover with one skid about a foot above the roof of a vehicle to remove passengers. The crew wears inflatable flotation devices as well as being secured by a full-body harness. Being this close to the water, a serious issue that the crew must watch out for is debris washing down and possibly hitting the tail rotor. They will then put a rescuer out onto the vehicle, who puts a personal flotation device (PFD) on the victim and gets them into the helicopter. One of the dangers at this particular moment, according to experts, is that as you remove the weight of the vehicle’s passengers, the car gets lighter and might begin to be pushed downstream. The team cannot put the skid on the roof of the vehicle in an effort to hold it steady, as by doing so they could possibly dislodge it from whatever is holding it in place in the moving water.

The AZDPS is also trained to use a short-haul rope system to place the rescuer in the eddy of the vehicle on the downstream side. In this scenario, the rescuer then moves onto the vehicle and disconnects from the line. He then secures the victims in a harness, and they are all short hauled to a safe location on the bank. The short-haul rope for water rescues is attached directly to the cargo hook of the helicopter so the pilot can release it if it gets entangled and endangers the ship. The helicopter is flown at a very low level with the rescuers and victims on the short haul rope. In case the pilot does have to release the line, the fall is short and not lethal.

The state of Texas can see a wide variety of flood events – thunderstorms, for example, can produce flash floods or inundate a few neighbourhoods over a small area. Hurricanes, meanwhile, can produce widespread flooding as happened in Houston, Texas, during Hurricane Harvey in 2017. During prolonged inclement weather, flood rescues become even more challenging. One of the most experienced rescue organisations in the state is Travis County STAR Flight, a civilian EMS and rescue helicopter agency with three hoist-equipped Airbus H145 helicopters.

“Weather can be a huge factor in flood rescue events,” explained Mike Summers, a flight medic and Crew Chief with STAR Flight. “Low clouds, rain, wind gusts, and lightning can interfere with flight operations. With land rescues, the patient may be in an area difficult to access, but they aren’t moving. In water rescues, they can be moving, which increases the difficulty and danger to the rescuers and victims. If they are holding onto an object, such as a tree or vehicle, fatigue and hypothermia can cause them to lose their grip and get carried away by the moving water. So, a helicopter rescue team must act quickly.”

Danger to life

Assessing the scene requires considering the risks to the victims and the rescuers

Assessing the scene requires considering the risks to the victims and the rescuers. Any time a rescuer is put into moving water, the AZDPS has to consider moving debris such as propane tanks, pieces of homes, furniture, and refrigerators, as well as fixed obstacles such as barbed wire fences and water features, which can suck a rescuer and their victim underwater.

All of our rescue swimmers and crew chiefs, said Summers, maintain their hepatitis A vaccinations due to raw sewage often being in the water in wide area floods. In addition, there are often fertilisers, pesticides, petroleum products and other pollutants in the water. So, the rescue swimmers always wear a dry suit for flood events. Another very real danger is wildlife. In central Texas, water moccasins (a poisonous snake) and fire ants will gather in balls for safety as they get pushed through moving water. As soon as they encounter something stable, they will latch on to it, which might be a rescue swimmer. Other places in the southern US have alligators that end up in neighbourhoods due to flooding.

Since many of the flood events occur in the hotter months of the year, the rescue swimmers must be monitored for heat illness due to being in a dry suit. They have to stay hydrated and eat often as well as take regular breaks during long-lasting flood events so they can do their job and not end up as a victim.

Victim prioritisation

In a wide-area event, such as a hurricane, there can be many victims that need to be rescued. There may be entire neighbourhoods that are flooded, with hundreds of people either stranded inside flooded homes or on the roofs. In these situations, say experts, you have to determine who needs to be rescued first and who can wait. You also have to predict how long the event will last to determine fuel needs, crew rest, and whether or not there is a need to obtain more rescue resources, etc. The water may rise and fall quickly, in a matter of hours, or the water level may stay high for days. If the water is receding rapidly, the victims on the roofs may be safe until ground units can reach them. Then, the air resources can concentrate on the victims in higher risk locations or those who have been swept away.

“The height of the buildings is important when assessing the risk to victims,” Mike Summers said. “With a two-storey house, the residents may only have to go to the second floor to reach safety. With a single storey home, they may have to go into the attic or onto the roof. If they go into the attic and the water continues to rise, they are at much higher risk. So, it is important to have information about what the water level is going to do in the next several hours when assessing a situation. In addition, you have to be flexible when developing a rescue plan because things can change quickly. If an otherwise safe building with victims on the roof suddenly collapses and dumps people into moving water, everything changes.” Summers continued: “We have a breaching kit if we have to get through a roof to victims in an attic. We try to use a vent as a breaching point because it can be difficult to cut through a roof. Here in Texas, many roofs are metal. The kit includes a battery-operated reciprocating saw with multiple blade types as well as hand tools for cutting and prying.”

STAR Flight also trains its crews to access and remove victims through windows. During this training, they are taught about the different types of windows found in residential and commercial buildings, and how to insert a rescuer through the window. This type of hoist rescue requires a high level of skill and communication between the pilot and hoist operator as well as the rescuer on the hoist. Windows are typically no more than three feet by four feet, which is a very small target for rescuers to hit to achieve a successful hoist operation.

Many of STAR Flight’s rescues, said Summers, occur in swift water events such as flash floods with the victims situated in trees. The technique in this situation is that once a victim has been identified in a tree, the team try to mark their location with a lightstick so they don’t lose track of the victim – easily done in a large grove of trees. Next, they assess exactly where the victim is located in the tree. They might be secure, sitting in a fork of the tree well above the water. In that case, the helicopter can be brought in directly over the victim and use the rotor wash to blow apart the tree limbs, making the hoist relatively straightforward.

However, if the victim is lower down or partially in the water, the rotor wash might end up dislodging them into the moving water. In this situation, the crew must lower the rescue swimmer outside the canopy of the tree to the altitude of the victim. The helicopter will then move the rescuer into the tree using radio directions from the rescuer. The highest-risk part of this rescue evolution is the extraction after the rescuer has reached the victim, as this is when the chance of cable entanglement is greatest. Good communication among the entire team is crucial, especially at night.

“One of the key training points for us with flood rescue events is to minimise time of exposure for the victims and the rescuers,” Summers emphasised. “The quicker we are able extract the victim from the water, the less exposure to hazards for both the rescuer and the victim. It also reduces the risk to the helicopter and crew.”

A huge issue that must be addressed is the fact that many victims in a wide area flood event may be elderly, have medical conditions, or are very young infants and toddlers, and thus may be much more difficult to fit into rescue devices and be safety hoisted into the helicopters. Another issue is that many people will not leave their pets behind, say the experts. Many times, the people who do not evacuate when told are those who are infirm and have mobility issues.

STAR Flight carries some rescue devices that work well for these kind of patients. One wraps around the victim’s back and upper legs with straps that come up between their legs and under their arms to cradle them like a large diaper, keeping the person in a seated position so they can be safely hoisted. They also have devices that can hold small children and infants. Sometimes, the rescue swimmer has to be creative to safely secure victims with special needs or those who are very small – they will take pets and have hoist harnesses for dogs, as well as enclosed devices for smaller animals to protect the animal and rescuers.

Another option for rescuers who are tasked with saving lives in flood waters is the Airborne Tactical Extraction Platform (AirTEP), manufactured by Capewell. The AirTEP device itself was developed in France by Escape International, and it is engineered to be versatile and straightforward to use. It is lightweight and simple to deploy via helicopter cargo hook, and it collapses for easy transportation and storage. The device is built around a centre post that connects via 80’ line to the cargo hook. Five hinged ‘ribs’ fold out from the centre post to form the structure for the pentagonal platform made of heavy duty Kevlar webbing.  The webbing is thermal, abrasion and chemical resistant, which allows AirTEP to be used in harsh conditions on land or at sea. There are ten integrated personnel tethers that allow passengers to secure themselves directly to the centre post. Inexperienced passengers are usually seated with their backs to the centre post, while rescue personnel often prefer to clip in and stand.

“The real beauty of the AirTEP is its versatility,” Capewell’s President and CEO John Marcaccio told AirMed&Rescue. “It’s a huge asset in many rescue situations. The floods following Hurricane Harvey in Texas are a good example. Hundreds of victims were rescued by helicopters one-by-one. With the AirTEP, multiple people could have been rescued in a single trip. That means a lot when whole families are stranded in yards or on rooftops in the middle of raging flood waters.”

A joined-up approach

Flood events can be very sudden or be anticipated several days ahead of time. They may involve a small dry wash or hundreds of square kilometers. Victims are of all ages, sizes, and physical capabilities. The key to successful helicopter rescue during these events is skill, the proper equipment, and the ability to quickly assess each situation and minimise risks of danger to the crew and the helicopter.

All images by Barry Smith