Terrain Assessment and Rope Rescue Strategy

Rope rescue technician students assist a litter over Class 3 terrain. The rescuers have spread themselves out on the difficult terrain and are passing the litter rather than carrying it. Photo Edith Pinson

Consider this scenario: Your agency is dispatched to a motor vehicle accident (MVA). As units respond to the call, the dispatcher relays reports that a car has driven or rolled off a steep bank and is located down a steep embankment in heavy brush. The first engine arrives on scene and reports that they have a car that’s approximately 200 feet down a steep ravine in heavy brush, and they’re attempting to access the patient. The engine company rigs an anchor to a large tree, dons Class 2 harnesses, and two of its members rappel down to the car using Rescue 8 plates for friction. They find that the patient is seriously injured and will need to be secured to a backboard prior to being brought back up the ravine to the transport unit.

The above scenario is probably one of the more common types of incidents that will require the use of a Stokes basket and rescue rigging skills. It’s usually not a high-profile event and will involve mostly grunt work on the part of the rescuers.

Many rescue teams focus on training for high-risk, high-angle rescues, but spend little time on the less-glamorous rescue scenarios that they’ll encounter. These less-dramatic rescues involve just as much, if not more, risk for the rescuers because they may underestimate the hazards. If a good plan is not in place, a long extraction time will most likely have a negative effect on the patient’s condition.

How many rescuers would you have available to perform this type of a rescue? How many do you need? Will you use a single- or a two-rope system? Should you raise the patient to where they departed the road or is it possible to continue down to the bottom of the ravine or hill?

Terrain Assessment & the High Angle
A terrain assessment is essential to determining what type of system you’ll use and what will be and will not be an acceptable means of accessing the scene/patient. There are many ways to review and evaluate terrain. High-angle is pretty straightforward: It’s vertical or close to it. Your sole means of support when dealing with high-angle terrain will be on the rope.

Rather than use a numerical rating (i.e., a 40-degree slope) when discussing high-angle terrain, a better way to assess it may be to evaluate the consequences of a system, or human failure. For example, you might say that the slope is steep enough and slippery enough to make walking or climbing upward difficult, so you may be able to go down, but going back up would be difficult. However, there are no hazards to slide into and no cliff at the end of a run-out. If the rope were to fail, you would suffer no injury. This can also be referred to as Class 2 terrain (see sidebar).

Note: When performing a terrain assessment, keep in mind that there’s a difference between assessing the terrain that an experienced, individual rescuer will travel over to access a patient and the movement of an injured patient in a litter over that same terrain.

Use of Litter Attendants
The number of litter attendants is in direct correlation to the angle of the slope. The steeper the slope, the fewer attendants you’ll need. If the slope is vertical, you’ll need one or none. The litter attendant is there to prevent the litter from getting stuck on something and to reduce friction by pulling the litter away from terrain. So on flat terrain, you’d want litter attendants and the ability to change them out, or at least change sides often, since they’d be carrying 100% of the patient’s weight.

But if the terrain is smooth, like a grass- or snow-covered slope, do you really need litter attendants? Could rescuers walk alongside the litter to guide it and ensure that the litter doesn’t roll over? This would certainly reduce the weight on the system and make it easier for the haul team on a raise. Often in Class 3 terrain, this is an ideal way to move a patient; however, downed trees, stumps and rocks can prevent this from working, so we have the option of using litter attendants.

The weight of four litter attendants, a patient and the litter will put more strain on a system in a Class 4 or 3 environment than there would be on a system used in Class 5 terrain with a litter attendant, patient and litter. But many times, we underestimate the amount of weight we expect the system to support. People casually say “it’s only low-angle terrain,” and that’s true; the consequences of a system failure will not cause critical injury or death. However, if you’re one of three or four litter attendants attached to a litter when there’s a system failure, you won’t appreciate being attached to a litter as it falls backward with multiple people attached to it.

To help determine appropriate rigging for a litter attendant, ask yourself the following questions:

  • If I let go of the litter, will I be critically injured or killed?
  • Is there a chance of injury if I continue down the slope on my own?
  • Will something bad happen to me if I let go of the litter?

If the answers to the questions above are no, then the litter attendants should not physically attach themselves to the litter with a strap or tether (a strap may be used to move the litter weight onto the attendant’s shoulder, but it’s hand-held).

If you answer yes to any these questions, then all attendants working in Class 5, 4 or 3 terrain should be attached to the litter, which means they should also use a two-rope system. For Class 5 and 4 terrain, litter attendants should always have a second point of attachment. For Class 3 terrain, it’s up to the attendant and their organization as to whether they will use a second point of attachment for the litter attendants.  

Getting the Litter to the Patient
In Class 2 terrain, you may elect to have rescuers carry the litter to the patient without a rope and then connect a rope as needed. In situations where the terrain will be changing, I like to tie a piece of webbing to the head of the litter so that I can clip and unclip a rope to it. The rope will function as a belay line while I move up and down slopes or in areas where dropping the litter could result in injury to the patient. Note: This is an exception to the direct tie-in rule for belay lines, but remember we’re talking about Class 2 terrain.

If the terrain is Class 3—where using a rope would make it easier for the rescuer to get up and down the slope and a failure would not have serious results—then a single rope may be used to lower both the rescuers and litter. The rope may be attached to the litter with a webbing sling or a two-leg litter spider. But as the litter spider attachment point varies with litters, you’ll need to determine where the best attachment point for your litter will be. Friction may be a brake rack, Rescue 8 plate or a Munter hitch.

Once the litter is with the patient and it’s been determined that litter attendants will need to be attached to the litter, a second rope (belay line) needs to be rigged. This could have been pre-rigged from the start, or, if the initial rescuers used a rope to gain access to the scene and are no longer relying on it, then their access rope can be converted to a belay line. The end of the rope at the litter would be directly tied to the head of the litter, and the end that’s secured to the anchor could have a friction device applied (tandem Prusiks, multi-purpose device, 540 or an I’D, for example).

The Belay Technique
The technique that we select for belaying should be based upon the type of terrain that the litter is going to travel. If litter attendants are carrying and passing the litter over changing Class 2 terrain and/or they’re on sloping terrain where the litter will travel rapidly, a “quick belay” would be appropriate. A friction device wrapped around a boulder or a tree would be sufficient; it’s quick and easy to set up and take down because there’s no need to build an anchor.

Class 3 terrain with litter attendants carrying the litter by hand only can be belayed with a Munter hitch. It’s quick to rig and can easily tension the rope while the litter ascends, and it can feed rope as the litter descends. If the litter attendants determine that they need to be attached to the system, then a tandem Prusik belay would be the appropriate belay system.

Both Class 4 and Class 5 terrain, with or without litter attendants attached, would call for a tandem Prusik belay. Once a terrain assessment has been made, the type of rigging needed to access and remove a patient will be straightforward.

So What Happened to the Patient in the Car?
The company officer called for a technical rescue response. The initial rescuer rappelled using a single-rope technique over what he thought was Class 3 and 4 terrain. The terrain changed to Class 5 for a portion of his descent.

Another challenge: The vehicle was actually 230 feet down the slope, not 200 as originally thought. So, because the rescuer was using a 200' rope, he had to carefully descend the last 30 feet without a rope in Class 3 terrain.  

The seriously injured patient was extricated and placed on a backboard and then in a Stokes litter. Rescue techs at the crash site determined that, due to the type of terrain and distance to the water, where a rescue boat was waiting, it would be easier to lower the patient 30 feet further down the hillside to the train tracks below.

The railroad company was notified to halt train traffic, and the patient was lowered on a single rope over Class 3 and 4 terrain, with attendants moving alongside the litter. From the tracks, a quick belay technique was used to move the litter the last 12 feet to the shore of Puget Sound.  The rescuers carried the patient through knee-deep water to the department fire/rescue boat. The patient was transported to a nearby marina where a medic unit met them and transported the patient to the hospital.

Sidebar: Terrain Classifications
Here is a list of the classifications for assessing terrain and what types of rope systems would be appropriate for moving a litter basket with a patient in each class. In addition to the angle of the slope, it’s important to also consider the type of terrain you’ll be travelling on (e.g., hard, packed dirt; loose rocks; running sand; snow; ice; etc.) Note: This list refers to rope systems that should be used by a litter and a patient only. If you’re going to have litter attendants attached to the litter, then a second rope is appropriate. (See the litter attendant section for more information).

  • Class 5: This is technical terrain. The patient’s weight will be on the rope system. A failure of this system will result in critical injury or death, so for safety reasons, use a two-rope system (main and belay).
  • Class 4: This may be changing terrain and/or simply steep and dangerous terrain. Rescuers will need to use their hands and feet to ascend or descend. Although not vertical, the consequences of a system failure may result in critical injury or death. Use a two-rope system.
  • Class 3: An individual may scramble un-roped, but they may need to use their hands as well as their feet to traverse the terrain safely. A falling litter may result in serious injury of the patient. Use a single rope to raise or lower the litter.
  • Class 2: This involves a slope that a rescuer can walk on using only their feet for balance. A slip or fall will result in them simply sitting on the slope, but a dropped litter may slide down the slope, resulting in injury to the patient. Use a single rope to belay the litter.
  • Class 1: A flat trail.

Note: This system has been used by climbers for more than 70 years. It’s a good tool to assist you in your terrain assessment. You can see how the term “steep angle” would be ambiguous and doesn’t paint a clear picture of the hazards. It’s easy to underestimate the environment in this situation, so carefully evaluate the terrain further down the slope. Can you visually see all of the terrain, or is part of it obscured by bushes or trees? It’s not unheard of to start what you think is a rappel over Class 3 terrain and end up hanging in Class 5 terrain.

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November 2017
Volume 12, Issue 11