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Humans at Earth’s Extremes:. Death in Death Valley. Frederick F. Andres, Ph.D . Amy L. Morgan, Ph.D. Bowling Green State University. Surfwithberesek.com/death-valley . Humans at Earth’s Extremes: Death in Death Valley. Boy, 11, dies while stranded in Death Valley
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Humans at Earth’s Extremes: Death in Death Valley Frederick F. Andres, Ph.D. Amy L. Morgan, Ph.D. Bowling Green State University Surfwithberesek.com/death-valley
Humans at Earth’s Extremes:Death in Death Valley Boy, 11, dies while stranded in Death Valley Mother, dog survive ordeal in ‘remote and isolated’ area of national park http://www.msnbc.msn.com/id/32340356/ns/us_news-life/t/boy-dies-while-stranded-death-valley/
Humans at Earth’s Extremes:Death in Death Valley “…desert valley located in eastern California.” “Situated within the Mojave Desert, it features the lowest, driest, and hottest locations in North America.” Wikipedia
Humans at Earth’s Extremes:Death in Death Valley Coordinates: 36 degrees 14 minute 48 seconds North 116 degrees 49 minutes 01 seconds West Elevation: – 86 m (- 282 ft) Wikipedia NEVADA CALIFORNIA *
Humans at Earth’s Extremes:Death in Death Valley Location: In the Great Basin East of the Sierra Nevada Mts. Borders N: Sylvania Mts. S: Owlshead Mts. E: Amargosa Range W: Panamint Range www.lib.utexas.edu/maps/national_parks.html
Humans at Earth’s Extremes:Death in Death Valley Area: 7, 800 km2 (3,000 mi2) Climate Hot and Dry!! Temperature High: 91. 4o F (33o C) Low: 62. 9o F (17. 17o C) Precipitation 2. 36 in (59. 9 mm) www.printedimagechico.com/product/nature-fact...
Humans at Earth’s Extremes:Death in Death Valley “…called Death Valley by prospectors and others who sought to cross the valley on their way to the gold fields….” Wikipedia www.nasa.gov/topics/earth/features/20090629.html
Humans at Earth’s Extremes:Death in Death Valley • Desert Hazards • Water • Heat/Dehydration • Hiking/Driving • Flash Floods • Dangerous Animals • Mine Hazards Experience is a hard teacher. She gives the test first, the lesson afterwards. http://www.nps.gov
Humans at Earth’s Extremes:Death in Death Valley "It's important for people to know that only a tiny portion of Death Valley has cell phone reception." Search/Rescue Coordinator: Micah Alley “…there is no cell phone reception in Death Valley. Depending on service provider and type of phone, some areas may have limited reception, but it is sparse and unpredictable.” Furnace Creek Resort Death Valley National Park
Humans at Earth’s Extremes:Death in Death Valley A satellite telephone, satellite phone, or satphone is a type of mobile phone that connects to orbiting satellites instead of terrestrial cell sites. Satphones are popular on expeditions into remote areas where terrestrial cellular service is unavailable. Wikipedia Choose your satellite phone. Starting at only: $8.99/Day
Humans at Earth’s Extremes:Death in Death Valley 'Death by GPS': Could it happen to you? By Wilson Rothman “…they can't tell you if a road was closed since you bought the device, and they can't tell you of any hazard advisories put out by the local authorities.”
Humans at Earth’s Extremes:Death in Death Valley "She turned down a wrong road. She said she was following her GPS unit.“ Ranger Amber Nattrass Alicia and Carlos Sanchez
Humans at Earth’s Extremes:Death in Death Valley "People are renting vehicles with GPS and they have no idea how it works and they are willing to trust the GPS to lead them into the middle of nowhere.” DV Wilderness Coordinator: Charlie Callagan You can’t be lost if you don’t care where you are.
Humans at Earth’s Extremes:Death in Death Valley Using GPS NavigationGPS Navigation to sites to remote locations like Death Valley are notoriously unreliable. Numerous travelers have been directed to the wrong location or even dead-end or closed roads. Travelers should always carry up-to-date road maps to check the accuracy of GPS directions. DO NOT DEPEND ONLY ON YOUR VEHICLE GPS NAVIGATION SYSTEM. National Park Service Announcement Good judgment comes from experience, and experience comes from bad judgment.
Humans at Earth’s Extremes:Death in Death Valley • Drink plenty of water, at least a gallon a day, more if you are active. • Don't hike in the heat of the day, and don't drive off-road.• Tell someone where you are going.• Take a map and know how to use it.• Be wary of GPS units, which have led visitors astray.• Carry extra water in your vehicle in case of emergency.• Talk to a ranger about park and weather conditions.• If you visit backcountry, carry a personal locator beacon or similar device. Good judgment comes from experience, and experience comes from bad judgment.
Humans at Earth’s Extremes:Death in Death Valley Goals: • Mechanisms of body temperature regulation • Effects of dehydration • Comparison of children to adults • Applications to NW Ohio
Thermoregulation: Humans are “homeothermic” i.e., relatively constant Tbody independent of temperature of surrounding environment Normal Tbody = 36.1 to 37.8 °C (97.0 to 100.0 °F) Importance of homeostasis Heat transfer depends on temperature gradient between skin and environment Heat moves ‘down’ the gradient Humans at Earth’s Extremes:Death in Death Valley
Humans at Earth’s Extremes:Death in Death Valley To maintain body temperature, heat loss must balance with heat gain Dehydration challenges ability to lost heat via evaporation…
Humans at Earth’s Extremes:Death in Death Valley Transfer of Body Heat • Conduction • Direct molecular contact • Example: heating pad • Convection • Heat transferred to air or water • Can trigger heat heat • Examples: breeze, fan • Water >> air in thermal convection!
Humans at Earth’s Extremes:Death in Death Valley Transfer of Body Heat • Radiation • 60% of heat loss at rest • Also a mechanism of heat gain • Infrared/electromagnetic heat waves • Example: sun
Humans at Earth’s Extremes:Death in Death Valley Transfer of Body Heat • Evaporation (rest=10-20%; exercise=80%) • Fluid (water) changes to vapor, taking heat with it • Example: sweating • Key factors: • Temperature, relative humidity • Clothing • Convective currents around body • Skin exposure
Humans at Earth’s Extremes:Death in Death Valley Control of Heat Exchange • Hypothalamus = thermostat • Anterior = reaction to ↑ temperature • Posterior = reaction to ↓ in temperature • Thermoreceptors • Central - blood temperature in hypothalamus • Peripheral – skin temperature
Humans at Earth’s Extremes:Death in Death Valley Variables of Environmental Heat Load • Air temperature • Humidity • Air velocity • Amount of thermal radiation Heat Index vs. WBGT? • Heat Index – how hot does it feel? • WBGT (wet bulb globe temperature) • reflects physiological heat stress • takes convection, radiation & evap. into account
Humans at Earth’s Extremes:Death in Death Valley Effectors for Temperature Control in Heat • Sweat glands • Arterioles • Blood to surface • Blood redistribution
Humans at Earth’s Extremes:Death in Death Valley • Cutaneous vasodilation – moves blood to surface to release heat to environment, i.e., down temperature gradient • Sweating leads to water loss → dehydration
Humans at Earth’s Extremes:Death in Death Valley Impact of dehydration • Electrolyte imbalance • ↓ blood volume • ↓ blood available for periphery • ↓ sweating • ↑ Tcore • ↑ heart rate (↑ metabolism) • ↑ risk of heat-related illness
Humans at Earth’s Extremes:Death in Death Valley Signs of dehydration • Thirst • Dry or sticky mouth • Headache • Weakness • Dizziness • Cramping • Irritability • Extreme fatigue
Humans at Earth’s Extremes:Death in Death Valley For more information: http://www.webmd.com/a-to-z-guides/understanding-heat-related-illness-symptoms
Humans at Earth’s Extremes:Death in Death Valley Responses in children*: • Higher BSA/mass ratio aids in more heat dispersal • However…advantage disappears when Tair > Tskin(~95ºF) • Lower sweating rate (…less cooling) • Onset of sweating later (@ higher temp) • *Most comparison data with adults from exercise studies
Humans at Earth’s Extremes:Death in Death Valley Death Valley: 100°F 20% Humidity Heat index = 97°F Toledo, OH: 90°F 80% Humidity Heat Index = 113°F • http://www.usatoday.com/weather/wheat3.htm • http://www.hpc.ncep.noaa.gov/html/heatindex.shtml
Humans at Earth’s Extremes:Death in Death Valley → Be cautious when heat index is high – does not only happen in the desert! → Drink plenty of water. → Breeze or fan is good! → Stay out of direct sunlight. → Wear clothes that ‘breathe’.
Humans at Earth’s Extremes:Death in Death Valley Thank you! Questions?