Modern avalanche transceivers, shovels and probes are now standard in ski touring. Along with a rise in the uptake of avalanche courses and increasingly efficient rescue teams, quicker detection and rescue of buried victims has also improved. The result: increased survival rates in avalanche burials over the past four decades.
“Up until 1990, 43.5% of buried victims survived; now, it’s 53.5%,” explains Simon Rauch, the study’s lead author and an emergency physician at Eurac Research. “We analyzed data from 1981 to 2020 and compared it with a 1994 Nature study that covered a ten-year period.
The new analysis also shows that the survival probability for long-term burials (over 130 minutes) has increased from 2.6% to 7.3%. The average rescue time has dropped from 45 minutes to 25 minutes. Rescue time decreased from 15 to 10 minutes in cases when a companion was present, while organized rescue times fell from 153 to 90 minutes. However, the phase where survival probability exceeds 90% has shortened from 18 to just 10 minutes.
The findings are published in the journal JAMA Network Open.
“In 1994, we divided the survival curve into different phases and discovered that the first phase, when survival rate is very high, lasted up to 18 minutes. This became a global reference point in mountain rescue, but it now needs to be modified,” says Hermann Brugger of Eurac Research, author of the original 1994 study and co-author of the current one.
There are only hypotheses for the drastic reduction in this time window. “It could be that due to climate change and other factors, snow density has increased. The denser the snow, the less air it contains, making it harder to breathe under the snow,” Rauch suggests. However, this theory has yet to be confirmed by data.
“Time is the critical factor, and ten minutes is not long. Therefore, it’s essential to understand that the survival chances in an avalanche burial are three times higher when excursion companions are able to dig out the victims, rather than when organized rescue teams are involved,” Rauch emphasizes.
The study also highlights preventive measures such as avalanche warning services, training for ski tourers, and advancements in location and rescue techniques, along with improved emergency medical care, have significantly reduced the mortality rate for avalanche victims in recent decades.
WSL, the Swiss Institute for Snow and Avalanche Research provided the data for the study, with biostatistician Markus Falk contributing a statistical analysis using a complex model.
More information:
Simon Rauch et al, Avalanche Survival Rates in Switzerland, 1981-2020, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.35253
Provided by
Eurac Research
Citation:
Survival rate for avalanche burials has increased by 10% since 1994, finds new analysis (2024, September 26)
