Surfwithberesek.com/death-valley Humans at Earth’s Extremes: Death in Death Valley Frederick F. Andres, Ph.D. Amy L. Morgan, Ph.D. Bowling Green State.

Surfwithberesek.com/death-valley

Humans at Earth’s Extremes:

Death in Death Valley

Frederick F. Andres, Ph.D.

Amy L. Morgan, Ph.D.

Bowling Green State University

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)

ClimateHot and Dry!!TemperatureHigh: 91. 4o F (33o C)Low: 62. 9o F

(17. 17o C)Precipitation2. 36 in (59. 9 mm)

www.printedimagechico.com/product/nature-fact...

Humans at Earth’s Extremes:Death in Death Valley

www.nasa.gov/topics/earth/features/20090629.html

“…called Death Valley by prospectors and others who sought to cross the valley on their way to the gold fields….”

Wikipedia

Humans at Earth’s Extremes:Death in Death Valley

http://www.nps.gov

Desert Hazards

•Water

•Heat/Dehydration

•Hiking/Driving

•Flash Floods

•Dangerous Animals

•Mine HazardsExperience is a hard teacher. She gives the test first, the lesson afterwards.

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 ResortDeath 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 CallaganYou 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

Good judgment comes from experience, and experience comes from bad judgment.

• 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.

Humans at Earth’s Extremes:Death in Death Valley

Goals:1. Mechanisms of body temperature

regulation

2. Effects of dehydration

3. Comparison of children to adults

4. Applications to NW Ohio

Humans at Earth’s Extremes:Death in Death Valley

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

To maintain body temperature, heat lossmust balance with heat gain

Dehydration challengesability to lost heat viaevaporation…

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

Humans at Earth’s Extremes:Death in Death Valley

http://www.usatoday.com/weather/wheat3.htm

http://www.hpc.ncep.noaa.gov/html/heatindex.shtml

Death Valley:100°F20% Humidity Heat index = 97°F

Toledo, OH:90°F80% Humidity

Heat Index = 113°F

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

Questions?

Thank you!