They are also expensive and vulnerable to damage from falling rocks in the warmer months. In addition to industrially manufactured barriers, landscaped barriers, called avalanche dams stop or deflect avalanches with their weight and strength. These barriers are made out of concrete, rocks, or earth. They are usually placed right above the structure, road, or railway that they are trying to protect, although they can also be used to channel avalanches into other barriers. Occasionally, earth mounds are placed in the avalanches path to slow it down. Finally, along transportation corridors, large shelters, called snow sheds, can be built directly in the slide path of an avalanche to protect traffic from avalanches. Early warning systems
Warning systems can detect avalanches which develop slowly, such as ice avalanches caused by icefalls from glaciers. Interferometric radars, high-resolution cameras, or motion sensors can monitor instable areas over a long term, lasting from days to years. Experts interpret the recorded data and are able to recognize upcoming ruptures in order to initiate appropriate measures. Such systems (e.g. the monitoring of the Weissmies glacier in Switzerland) can recognize events several days in advance. Alarm systems
Modern radar technology enables the monitoring of large areas and the localization of avalanches at any weather condition, by day and by night. Complex alarm systems are able to detect avalanches within a short time in order to close (e.g. roads and rails) or evacuate (e.g. construction sites) endangered areas. An example of such a system is installed on the only access road of Zermatt in Switzerland.
Individuals carrying this deficiency are relatively "normal", as in they do not possess any major birth defects or major medical illnesses. This microduplication is more common than the deletion; this might relate to the milder phenotype of the individuals. 22q13 deletion syndrome (Phelan–McDermid syndrome) is a condition caused by the deletion of the tip of the q arm on chromosome 22. Most individuals with this disorder experience cognitive delays, low muscle tone, and sleeping, eating, and behavioural issues. Chromosome ring 22 is a rare disorder caused by the break and rejoining of both ends of chromosome 22, forming a ring. The effects on the individual with this disorder are dependent on the amount of genetic information lost during the process. Major characteristics for this disorder are intellectual disability, muscle weakness, and lack of coordination. Cat eye syndrome (Schmid Fraccaro syndrome) is a condition caused by a partial trisomy or tetrasomy in chromosome 22. A small extra chromosome is found, made up of the top half of chromosome 22 and a portion of the q arm at the q11.2 break. This chromosome can be found three or four times. This syndrome is referred as "cat eye" due to the eye appearance of reported affected individuals who have coloboma of the iris, but this feature is only seen in about half of the cases. Mosaic trisomy 22 is a disorder in which an extra chromosome 22 is found only in some cells of the body.