Sports and recreation
Hiking
Estimated acute risk associated with recreational hiking on established trails.
Base risk estimate
0.10 micromorts per hours
Population-level estimate. Not a personal prediction.
Assumptions
Assumes recreational hiking on established, marked trails by a generally healthy adult. NPS SAR fatality counts are extrapolated to total US hiking using trail-mile and visitation fractions.
Limitations
NPS SAR fatality categorization (hiking vs. other) is not published at a granular level; the fraction attributed to hiking is estimated. The NPS-to-total-US scaling introduces additional uncertainty. Risk varies substantially by terrain, elevation, weather, party size, navigation skill, and remoteness. This estimate does not apply to backcountry or off-trail travel.
Source notes
Derived from NPS Annual SAR Summary 2022 and SFIA hiking participation data. NPS SAR Summary 2022 documents approximately 3,200–3,500 total SAR operations across NPS units, with approximately 150–180 fatal outcomes (all causes). Hiking and trail-related incidents are the largest SAR category, estimated at 40–50% of total NPS SAR fatalities, yielding approximately 60–90 hiking-related fatalities in NPS units per year. NPS trails represent approximately 25–35% of total US trail use by hours (based on NPS's ~80,000 miles of trails relative to ~200,000 total US trail miles and high NPS visitation intensity). Extrapolating to total US hiking: approximately 200–300 hiking fatalities/year. SFIA 2022 reports approximately 58 million US hikers; applying an estimated average of 10 outings/year at 2.5 hours each yields approximately 1.5 billion hiking hours/year. Derived rate: 200–300 / 1.5 billion = 0.13–0.20 µmt/hour; using 0.1 as a conservative estimate. The prior placeholder value of 0.002 µmt/hour was inconsistent with NPS SAR fatality counts.
Last reviewed
6/11/2026
How does this compare?
Activities with a similar per-unit risk level. Units vary — these are approximate comparisons.
Related activities
RiskLens is an educational tool. It uses population-level estimates to help explain relative risk. It is not a prediction of your personal risk and should not be used as medical, legal, financial, or safety advice.