Patterns of behaviour that pose potential drowning risk to hikers at Yosemite National Park.

PRIMARY OBJECTIVE: To analyse patterns of departure from a popular hiking trail in Yosemite National Park, at sites where fatal drownings have occurred in the past. METHODS: This study employed direct observation. For 32 days throughout the summer of 2013, study team members observed hikers who entered areas that brought them in close proximity to hazardous sections of the Merced River. Subject and environmental data were recorded for 1417 such approaches. RESULTS: In 81% of our observation hours, subjects entered 'risk zones.' The median number of hikers seen near/in the river was eight per hour at the Vernal Fall footbridge, and three at the top of the waterfall. A regression analysis found that air temperature and later hike starts were positively associated, and water level was negatively associated, with the rate of river approach. Means of river access were also identified. Males, teens and people who were alone were significantly more likely to be observed entering particularly dangerous areas. CONCLUSIONS: It is common for hikers to approach water sources during summer months, particularly as air temperatures rise. By analysing how behaviour and environmental factors co-vary, safety advocates can tailor risk reduction measures to specific settings and visitor populations.

Understanding hikers who approached a hazardous river in Yosemite National Park.

OBJECTIVES: To understand the perceptions and motivations of hikers who approached a swift river at locations that have been associated with drowning in the past. METHODS: A survey was completed by 399 adults who had been observed getting 'too close' to the Merced River. The questionnaire covered trail familiarity, information sources, timing and motivation of their decision, perceived safety, knowledge and opinion of park rules. RESULTS: Sixty-eight per cent of invited hikers agreed to participate. Almost all had received advance information about their hike, but most often that did not include a river warning. Most respondents were observed in the risk zone by the footbridge, and their most frequent motivation was to 'cool off'. Ninety-two per cent of hikers reported feeling very or somewhat safe by the river. Their risk perceptions did not correlate with expert ratings of danger. Males, younger subjects and those who had hiked the trail before were more likely to enter the most hazardous parts of the risk zone. Eleven per cent of people at the footbridge and 43% at the top of the waterfall thought that the park should not allow visitors to go where they had been. The most common reason they gave for this view was that the location was unsafe. CONCLUSIONS: While this needs assessment identified channels for informing hikers of drowning risk, there are indications that they might not personalise such warnings. Another option would be to explore cooling alternatives that could compete with the swift water that runs along many hiking trails.