Attempting to drive a vehicle across a flooded roadway is the initiating event for many vehicle-associated drownings. As a general rule, driving across a flooded roadway should be avoided.
Parameters:
(1) depth of water
(2) velocity of water flow
(3) weight of vehicle
(4) height of vehicle body above ground (clearance)
(5) presence of floating debris
(6) state of underlying roadway or bridge
(7) terrain downstream
(7) willingness to leave vehicle
(8) personal state of health
(9) presence and types of passengers
(10) presence of alternative routes
(11) necessity to reach destination
(12) seeing other drivers getting across the water
(13) 2 vs 4 wheel drive
(14) availability of a secure winch on the other side
Parameter |
Observations |
depth of water |
Water more than 2 feet deep can float a bus. A light car can float in a foot of water. |
velocity of water flow |
Flowing water can push a floating car downstream. |
weight of vehicle |
A light vehicle can float easily. |
clearance of vehicle |
A low slung vehicle is at greater risk for floating than a vehicle with a higher clearance. |
presence of floating debris |
Floating logs or debris can ram the vehicle as it attempts to cross. Moving debris indicates significant water velocity and indicates severe hazard. |
state of roadway |
Water covering a road or bridge can mask a serious defect in the roadway. You can never assume that the road is still there if you cannot actually see it. |
terrain |
The presence of rivers, ravines, chasms or other hazardous terrain adjacent to the roadway is a contraindication to crossing. |
willingness to leave vehicle |
Many drownings occur because the driver refuses to leave the car or tries to save it. |
personal health |
A person in poor health may be unable to escape if the vehicle is washed away. |
passengers |
The presence of infants, small children, elders or disabled persons increases the chances of drowning if the vehicle is washed downstream. |
alternative routes |
If the alternative route involves a long detour or is unavailable, then a person may be tempted to take a risk. |
necessity to reach destination |
Sometimes an emergency may cause one to take risks. However, many seeming emergencies are not so emergent in hindsight. |
other drivers crossing |
The failure of other drivers to cross is a good sign not to attempt the crossing. The ability of one vehicle to cross does not mean that another can do so successfully, because of differences in weight, roadway, water flow, or other factors. |
2 vs 4 wheel drive |
A 4-wheel drive is able to navigate obstacles better than a 2-wheel drive. However, this may give the driver a sense of overconfidence. |
secure winch on the other side |
The availability of a secure winch on the opposite can reduce but not totally eliminate the risk in attempting a crossing. |
Specialty: Emergency Medicine, Critical Care