Grand Canyon’s preventive search and rescue: patrols, heat data and a 95°F threshold

In the 1990s search-and-rescue incidents (SARs) at Grand Canyon National Park soared. From 1983 to 1996 they doubled, and summer 1996 set records that still stand: five heat-related deaths, 300 heat-related incidents and 482 SARs in total. In the late 1990s SARs cost taxpayers about $1 million a year on average. This account in Park Science by C. J. Malcolm and Hannah Heinrich tells how the park responded.

From reacting to preventing

Ken Phillips, then chief of Emergency Services at the park, describes a reactive routine: every summer day, when a hiker-in-distress call came in, the SAR shift scrambled someone down the trail from the South Rim, often running, in the heat, on vague reports that could mean a cardiac arrest or someone resting in shade. A couple of such calls a day wore rescuers out. After a decade of this and the record 1996, rangers were exhausted and disheartened, and park leadership commissioned a planning group of 10 rangers. They recommended the Preventive Search and Rescue (PSAR) team, set up in 1997 to reduce visitor injury, illness and death in the hottest months.

Other parks have taken the idea elsewhere. Yosemite introduced a permit system for the Half Dome cable route in summer 2010 after fatalities from overcrowding, and Delaware Water Gap uses it for water safety and life jackets.

What PSAR did

• Patrols. The original crew was four rangers on the Bright Angel and South Kaibab trails, plus volunteers.
• Messages. A "STOP, Heat Kills" campaign with trail signs, pamphlets and flyers.
• Access. The South Kaibab trailhead was closed to visitor parking, so hikers have to take the shuttle bus. Ranger Bill Vandergraff said this kept unprepared hikers off a steep, shadeless, waterless trail: before, people would drive up, look over the edge and get drawn in.

The original PSAR sign, used in the late 1990s. NPS Photo

Signs were updated between 2000 and 2010. The "STOP, Heat Kills" sign was replaced by a more positive but cautionary "Hike Smart" message. NPS

Today PSAR has seven seasonal rangers, one full-time supervisor and 60 trained volunteers, who attend two days of training at the end of April and two to three days shadowing rangers, for 30–40 hours in total. The season runs April through October, with most patrols from May to mid-September on the Bright Angel, South Kaibab, North Kaibab and Hermit trails. Rangers and volunteers stand at natural bottlenecks near rest areas to talk with hikers going deeper in about preparedness and safe hiking. All PSAR rangers are now certified as EMTs or paramedics, and are trained in search and rescue and technical rescue. The slogan has softened into "Hike Smart".

The legal backdrop

The Park Service classes a SAR as major if it costs over $500, and spends nearly $5 million a year rescuing visitors. In a 1992 landmark case, Johnson v. U.S. Department of the Interior, the 10th Circuit Court of Appeals ruled that search and rescue is a "discretionary function" of government: no statute imposes a duty to rescue, so whether, when and how is left to the team's discretion. The authors take this to reaffirm that backcountry dangers are obvious and safety is a personal responsibility, which is why the Service works to educate the public.

Bringing in science

From 2011 the team logged each patrol: trail hours, trails, "general contacts" (hikers spoken to), "preventive actions" (extra advice to someone poorly prepared), "hiker assists" (physical, medical or psychological help) and "major medicals" (paramedic-level care, often a litter carry or helicopter evacuation).

In summer 2015 the team contacted 117,267 hikers on the corridor trails, and 28,478 (24%) needed directive advice. Using weather data from Indian Garden Ranger Station, the team found a heat threshold. From 2011 to 2013, below 95°F (35°C), heat-related assists ran at 6.1 per 1,000 general contacts; at or above it, 10.4 per 1,000, a 71% increase. Summer 1996 had the most days above 95°F of any of the previous 25 years, 65, in the same year as its record SARs and heat deaths. With forecasts of 95°F or hotter, the team can add patrols and warn hikers.

New weather stations at Indian Garden (2014) and Phantom Ranch (2015) measure solar radiation, UV index, barometric pressure, wind, dew point and precipitation. They feed the Canyon Emergency Information System, designed and built by Dr. Hannah Heinrich, the program's chief scientific advisor, which is meant to power real-time displays at trailheads and ranger stations. In summer 2015 the team also ran a Hiker Hydration Study of more than 1,000 hikers over three weekends, with a 75% response rate, whose data were still being analyzed.

The authors say PSAR works a step behind the public: of the more than 117,000 people it met in summer 2015, more than 28,000 had to be persuaded to change plans.

Sources

• National Park Service, Park Science 33(1), "Preventive success! Grand Canyon's response to search-and-rescue overload", by C. J. Malcolm and Hannah Heinrich (https://www.nps.gov/articles/parkscience33-1_99-107_malcolm_heinrich_3864.htm); rewritten in hubnx's own words.