On Dec. 30, 2007, shortly before 6 P.M., Bonner Springs Police were dispatched on a report of a suicidal man who had cut himself with a knife and left the residence. When officers arrived on the scene, they discovered blood on the floor in the residence and a note the man had left stating he was going to kill himself. It was after dark and below freezing outside. Concerned for the man's safety, the officers used their flashlights to search a wooded park near the residence. After an unsuccessful search by flashlight, the officers requested a thermal imager (TI). Once the thermal imager was on-scene, the officers started searching again. Within five minutes of searching, officers had located a heat source within the park about 200 yards away. As the officers walked closer to the heat source, they discovered it was the suicidal man they had been looking for. The victim was lying in a thicket of grass at the base of a tree. His right wrist was deeply cut and bleeding severely. Officers assisted the man out of the park where he was treated by an ambulance crew.
Given the severity of the bleeding and the cold temperatures, the thermal imager was likely the difference between life and death for the victim, who went on to recover from his wounds. The officers involved in the search agree that the victim would not have been located if they had been forced to use only flashlights.
Lost or Missing Persons
Two major benefits of TIs in this type of situation are that the technology offers first responders the ability to see in otherwise poor visibility and it allows them to see signs hidden from regular human sight. Although this case involved a police department, many fire departments encounter rescue situations that can be positively impacted by the timely and effective use of a TI.
Both urban and rural rescuers can be called upon to locate lost or missing persons. The two most common missing person searches are based on the lost/runaway child or the walked-away senior citizen who may be afflicted by Alzheimer's, dementia or other organic brain syndrome. Disoriented hikers, hunters and other outdoors enthusiasts are also at risk of becoming lost and in need of rescue.
Whether lost in a park or in a cornfield, a person's heat signature can travel a greater distance than a rescuer's light. In areas with dense growth near the ground, rescuers will benefit from an elevated viewing position, accomplished with an aerial ladder or a nearby structure. Rain and snow can interfere with a person's heat signature. As rain cools the person's clothing or as snow builds up on the exterior, less of the person's body heat will emit toward the TI. This will reduce the range and effectiveness of the TI.
Alzheimer's patients can be a frequent urban search issue. While an adult search-and-rescue scenario may be similar to that of a child, adults are more likely to take protective measures, perhaps covering themselves to retain heat or seek protection from rain. As a result, they will unintentionally block more of their heat signature from reaching the rescuer's TI.
Rescuers should be looking for the obvious as well as the subtle heat signatures that seem out of place. Obvious heat sources are usually easy to spot and stand out against the background. As indicated in the story out of Bonner Springs, what the officers originally noticed was a heat signature that did not seem to fit in with the surroundings. They could not readily identify it from their position, but they investigated and located their victim.
More subtle heat sources may require a more discerning eye. This can involve a rock or log with a visible heat pattern or anomaly. Such an anomaly could indicate where your victim sat to rest indicating that you are heading in the right direction.
Law Enforcement Imagers
Another thing to consider when conducting a thermal imager search for a lost or missing person may be to request the use of an imager designed to be used by police. A law enforcement imager is typically equipped with optics designed for viewing at a distance. It has a much narrower field of view, which allows heat signatures to be seen at much greater distances. This is a benefit for law enforcement as distance increases safety; however, it is not good for the confined quarters inside a room.
The typical fire department thermal imager will be able to discern the heat signature of a person up to approximately 330 feet. The typical law enforcement thermal imager can discern a person at 3,300 feet. Find out if your police department owns an imager and, if so, whether it is designed for law enforcement. If so, consider calling out this imager during your next search and using it along with your imager.
Thermal imagers have become a common tool for emergency responders. As firefighters, EMTs and police officers become more comfortable with the technology, they will continue to use their TIs in more innovative and creative manners.
Thermal imagers can be a force multiplier in situations like search and rescue by allowing the rescuer to cover much greater distances in a much shorter period than could be done with a flashlight. Rapid victim location can make the difference between a happy ending and a tragic result. When called to these types of incidents, grab that thermal imager and put it to work. You never know when it might make a difference.
BRAD HARVEY is the Thermal Imaging Product Manager at Bullard. He is a veteran of public safety as a firefighter, police officer and paramedic and is certified through the Law Enforcement Thermographers' Association (LETA) as a thermal imaging instructor. Harvey has worked as a high-angle rescue instructor and is a certified rescue technician and fire instructor. If you have questions about thermal imaging, you may e-mail him at firstname.lastname@example.org.