If winter temperatures stay below freezing for long enough, layers of ice form on bodies of water in many places. For many people, this is an invitation to lace up their skates or take an extended ice walk.
To ensure that the pleasure remains one, the ice should not be stepped on too lightly – because in the event of a collapse, there is an acute danger to life after only a very short time. Our overview shows which rules should be observed.
Before setting foot on a frozen lake, canal or pond, find out if there may be warning signs for the body of water in question. Do not walk on ice surfaces that have not been expressly cleared for use.
Even if there have been several days of frost in a row and the ice layer appears sufficiently thick, laymen can hardly tell how load-bearing it actually is.
Minimum thickness of 15 centimeters for standing water
The German Life Saving Association (DLRG) recommends a minimum ice thickness of 15 centimeters for standing water such as ponds and lakes, and 20 centimeters for flowing water. The thickness of the ice depends on a number of factors. For example, the current on lakes can cause the ice to vary in thickness in different places.
"A crackle announces when the ice breaks"
Near large industrial facilities, the water may be warmer and the ice correspondingly thinner. Holes or cracks in the ice cover also affect its stability. "A crackling sound announces when the ice is breaking up," says Andreas Paatz, national director of the German Red Cross (DRK) water rescue team.
Anyone who notices such a sound should immediately leave the ice surface the same way they came in. In the process, one should crawl in order to distribute body weight as best as possible. If there are other people on the ice, they should also be warned.
Important: quick rescue
The greatest danger in the event of an ice collapse is hypothermia, which, depending on the water temperature and the state of health of the person affected, can occur after only a few minutes and can lead to drowning. Generally, in the event of an ice collapse or fall into cold water : the faster the affected person is rescued, the greater the chances of survival.
"For many years, four stages have been distinguished internationally after falling into cold water," says Dr. Ulrich Jost, medical officer at the DLRG in Bad Nenndorf. Water with a temperature of 15 degrees Celsius or less, in which the body is immersed up to the neck or even completely, is considered cold in this context.-Stage 1: Immersion reflexes and cold shock The cold stimulus on the skin initially causes the affected person to take a deep breath, which may lead to immediate drowning. Alternatively, the body reacts to cold exposure with a slowed or accelerated pulse, as well as an acceleration of breathing. Subsequently, restlessness, shortness of breath, dizziness, disorientation and panic can occur and even lead to drowning.
–Stage 2: Swimming failure In the following five to 30 minutes, nerves, muscles and joints fail due to the cold. Swimming becomes difficult to impossible. "In particular, the loss of fine and gross motor skills of the hands limit or make impossible the possibilities of self-rescue by grasping, holding on and swimming," says DLRG expert Jost.
–Stage 3: Hypothermia
In the following half hour, the entire body becomes increasingly hypothermic. This causes severe circulatory and respiratory failure, followed by unconsciousness and eventually drowning death.
–Stage 4: Collapse after rescue
Even after a possible rescue, the danger is not eliminated. There is still a risk of circulatory collapse for several hours. To avoid this, the victim should be warmed up again only slowly. To do this, bring him in a warm room, carefully remove the wet clothes and replace them with a warm blanket.
The affected person should be moved as little as possible. In the case of unconscious persons, breathing must be checked. If this is normal, the patient is placed in the stable lateral position. If breathing is irregular, the victim must be observed. If cardiovascular arrest occurs, cardiopulmonary resuscitation is required until rescue services arrive.
Self-rescue is already impossible after a few minutes
There is only a realistic chance of rescuing oneself from freezing water within the first few minutes of collapse. Afterwards the cold effect on the body makes a self-rescue impossible.
Depending on the nature of the ice, you should try to hold on to the ice and pull yourself onto it. If the ice continues to break, it is possible to break it off – as soon as it starts to bear again, it is possible to push or roll flat on it in a prone or supine position.
Extraneous rescue – only secured and lying down, better from land
Whoever rescues a collapsed person from the water should not put himself in danger in the process. If possible, rescue should be attempted from land and using aids such as boards, poles, inverted sleds, ladders, lines or branches.
If a rescuer goes onto the ice himself, he should never do so standing up, but lying down – and ideally secured with a rope – push himself forward to the point of collapse and push an aid over it. The rescue is much more complicated and dangerous if the person who has collapsed gets under the ice sheet.
Getting under the ice is especially dangerous
If the ice is too thick to break, rescue in such a situation can only be attempted by diving. It is imperative that the rescuer be secured by a tether during this process. Without shoes, but otherwise fully clothed, he dives under the ice for a maximum of 20 seconds.
"After this time has elapsed, the diver must be pulled out – even against his will," says Dr. Ulrich Jost of DLRG. Only those wearing diving equipment are allowed to carry out several diving attempts. In flowing water, diving under the ice cover is extremely dangerous and also pointless, because the injured person will drift away. The only possibility here is an emergency call as fast as possible.