Stranded by exhaustion during high-altitude mountaineering in the Swiss Alps: a nationwide retrospective study

Out of a total of 4687 emergencies (1027 women and 3660 men), the most common cause was blockage with 1951 cases (41.6%), followed by falls with 1348 cases (28.7%), illnesses with 352 cases (7.5%) and lost with 275 (5.8%) cases (Table 1). Being stranded is therefore by far the most common reason for receiving help from the emergency services. Of the 1,951 grounding cases, 1,557 were male climbers and 394 were female climbers. Grounding cases had a low mean NACA score of 0.32 ± 0.71; 1532 cases (78.5%) had a NACA score of 0; 296 cases had a NACA score of 1 (15.2%); 83 cases (4.2%) had a NACA score of 2; 27 cases (1.3%) had a NACA score of 3; 6 cases (0.3%) had a NACA score of 4; and 8 cases (0.004%) had a NACA score of 7; all eight cases with a NACA score of 7 were fatal (Fig. 1). Our analysis of changes in NACA scores over the observation period suggests that there was little change in injury severity (R2= 0.0002) (Fig. 2b).

Table 1 Overview of mountain emergencies.
Figure 1

Most of the victims were uninjured and only eight fatal cases could be identified. This is further evidenced by the average NACA score for the total sample of 0.32 ± 0.71.

Figure 2
Figure 2

(a) Stranding cases over the observation period (2009-2020) based on the regression model (n = 4.5629 * time + 132.09) with a high degree of detection of the variance of R2= 0.4398. A total increase from 137 to 187 cases of approximately 36% of cases is estimated, giving an average increase per year of 2.6%. (b) NACA scores of blocking cases during the observation period (2009-2020).

The mean age of women was 41.3 ± 11.3 years and the mean age of men was 42.8 ± 13.1 years, which was not significantly different (p= 0.186). The mean NACA score was 0.334 ± 0.62 for women and 0.319 ± 0.74 for men (p= 0.415).

The few cases where there was an injury were: 8 cases of leg injuries (6.5%), 33 cases of hand injuries (26.8%), 10 cases of shoulder (8.1%), 9 cases of knee injuries (7.3%), 13 cases of head injuries (10.6%), 12 cases of foot injuries (9.8%), 22 cases hypothermia (17.9%) and 16 cases of frostbite (13.0%).

During the observation period, an average of 161.8 ± 24.8 grounding cases were detected per year. According to our regression model, these cases increased over the observation period (not= 4.5629 * time + 132.09) with a high degree of variance, R2= 0.4398 (Fig. 2a).

Regarding the time of onset, the cases occurred mainly during the two summer months of July and August (Fig. 3).

picture 3
picture 3

Most groundings have occurred during the summer months of July and August.

The weather was a major cause of grounding. In 76 cases (12.7%), thunderstorms were identified as the cause, fog was identified in 73 cases (12.2%), weather changes in 59 cases (9.8%) and fresh snow in 34 cases (5.7%). However, the most common reason for stranding was exhaustion, with 357 cases (59.6%).

A very high proportion of cases involved popular mountain tours. Almost a third of the cases (551 cases, 28.1%) were near a summit over 4000 m, and a total of 1073 (54.9%) cases were on their way to a summit over 4000 m. Mr. There were 223 cases (11.4%) on the Matterhorn (Fig. 4) and 141 cases (7.2%) on Piz Bernina.

Figure 4
number 4

In nearly 80% of the cases analyzed, the climbers were not injured when they ran aground, often on a classic route on a summit over 4000 m. A typical grounding situation is shown on the left on the Zmuttgrat on the Matterhorn. The climbers overestimated their abilities and did not have enough time to return. A helicopter with longlines is then often the only possibility of rescue.

Regarding the nationality of the victims, 668 cases (34.2%) came from Switzerland, 426 cases (21.8%) came from Germany, 120 cases (6.1%) came from Italy, 110 cases (5.6 %) came from France and 85 cases (4.3%) came from Austria. Thus, about 70% were mountaineers from countries where the Alps are located. In addition, there were 81 cases from the Czech Republic (4.1%), 64 from Poland (3.2%), 64 from Great Britain (3.2%), 54 from Spain (2.8%) , 40 from the Netherlands (2%), 39 from Belgium (2%), 19 from Romania (1%) and 8 or less from Japan, Finland and Canada.