Tactical choices for rescues from vehicles in water

Introduction

Rescue from vehicles in water continues to be all too common during flood events and vehicles trapped in moving water can present great risks not only to their occupants but also to those undertaking the rescue.

Thankfully, the increase in the number of artificial white water courses has seen it becoming much easier to deliver realistic yet controlled training in this area. I can recall back in 2004 working with Martin Bills from Nottinghamshire Fire and Rescue Service and Tim Rogers from Charlotte Fire Department in the USA, on what was probably the UK’s first Rescues from Vehicles in Water workshop at the Tees Barrage Whitewater Course. Since then, many hundreds of responders have attended such workshops and the lessons learnt and techniques developed in these courses have been put to good use in real rescues on many occasions.

In this article, I will focus on the decision-making criteria that will drive tactical choice at these incidents. In the second article, I will look at techniques for performing rescues from vehicles in water.

Vehicle behaviour in water

There is no shortage of footage on YouTube etc showing people getting the car-versus-water equation wrong. However, these videos do confirm some of the key aspects of vehicle behaviour in
moving water, namely:

Vehicles will naturally pivot around the heaviest point (normally the engine). Generally, this means they will tend to move to facing upstream – unless it’s a VW Beetle!
Vehicles on hard surfaces under moving water that end up sideways to the current tend to roll over.

We can generally split rescues from vehicles in water into two categories:

Low energy shallow water where the vehicle has not moved – these are very common and vehicles are usually accessible using shallow water wading techniques.
Higher energy water where the vehicle has already moved (and possibly rolled). These can present much more complex rescue problems because of the higher energy water, potential damage to the vehicle and potential for t he vehicle to be trapped against an object restricting access to and egress from the vehicle.

Floating and/or moving?

One of the key considerations for anyone faced with undertaking a rescue from a vehicle in water is whether the vehicle is moving and/or floating and if not whether this could be the case in the
near future or during the course of the rescue?

The difference between the weight of the vehicle, its contents and occupants and the buoyancy force created by the vehicle displacing water will determine if the vehicle floats. Similarly, if the force
of any moving water acting upon the vehicle is greater than the frictional force between the vehicle and the surface it ‘s resting on then the vehicle will be moved by the flowing water.

Thus, depending upon water speed (if any) and depth of water, a vehicle could remain in situ, it could float but not be moved or it could be be moved downstream without floating.

Water level considerations

Given that water speed and water depth are two of the key factors that will determine whether a vehicle in water will move, these are priority considerations when undertaking rescues for vehicles in water. In particular, we need to consider the current water level and whether this is likely to increase/decrease. As soon as possible we need to be gauging the water level both at the rescue scene and where any upstream spotters have been located. This can be as simple as poking a stick into the riverbank to mark the current water level. Whilst we might anticipate water level rises and falls due to recent and current rainfall, snow thaw etc. by actually marking the water level as soon as possible we can quickly determine if there are any significant water level rises/falls and these in t rn will inform our decision making.

For example, faced with a car in flood water which has not yet moved, information from our on-site measurement that the water level is dropping will confirm that the vehicle is unlikely to move and may reduce the need to secure the vehicle prior to undertaking any rescue activities. Equally, faced with the same scenario but receiving confirmation from our measurement that water levels are increasing might confirm the need to secure the vehicle as a priority to prevent later movement as water levels rise. By training our first response crews on the importance of early water level
measurement we can provide critical risk information to specialist water rescue crews as they arrive on scene. There are other factors that affect a vehicle’s effective weight and buoyancy which in turn can determine if a vehicle will float and or move and these will be looked at later.

Are the occupants wet?

As we’ve seen above, having some knowledge on potential water level changes helps up determine priorities and actions. Equally information on the state of the vehicles occupants is
vitally important. Many factors such as the vehicle design and condition will determine if the occupants are still pretty much dry or whether they are sitting in cold water. If we have no vehicle movement worries and dry occupants we may have the time to apply techniques that allow for the occupants to be removed from the vehicle without getting them wet e.g. use of sled and boats. However, if the occupants are sitting in cold water and are already wet then removing them from the cooling effects of this water is time-critical especially if they are elderly or children or there are
medical considerations.

Paul O’Sullivan is the Managing Director of R3 Safety and Rescue – specialist rescue training and equipment supply business based in North Wales, UK. He’s been delivering swiftwater and flood rescue training for over 20 years and teaching Rescues from Vehicles in Water classes since 2004. He sits on the UK’s National Fire Chief’s Council Inland Water Technical Response Group.

This article originally appeared in Technical Rescue Magazine, and is reproduced with permission from the author.

Published: 07th Oct 2021