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Water Resources--Office of Water Quality

9.8 ENVIRONMENTAL CONDITIONS

Field work often is necessary under adverse atmospheric and other environmental conditions. Unpredictable occurrences, such as earthquakes, require event-response planning. Prepare for extreme conditions that might be experienced in your area of the country. Before leaving for the field, check the weather forecast using one or more of these options: the local television station, the national weather channel, the local land/marine weather band channel that constantly repeats current and future weather conditions, or computer networks such as the World Wide Web at http://www.intellicast.com.

9.8.1 TEMPERATURE AND SUN EXPOSURE

Extremes of air temperature occur in all parts of the country. The ideal comfort range for humans is between 16 to 32ºC (60 to 90ºF). Hypothermia and hyperthermia normally occur in temperatures outside this range.

Hypothermia is a condition of reduced body temperature caused by exposure to cold, and aggravated by wet clothes, wind, hunger, and exhaustion. Hypothermia in extremities can lead to frostbite. Hypothermia can occur with air temperature above 16ºC (60ºF) under wet and (or) windy conditions. The best way to avoid hypothermia is to dress warm and stay dry. Refer to Denner (Revised 1993) for information on cold-weather clothing.

The warning signals of hypothermia are uncontrollable fits of shivering, incoherence, listlessness, fumbling hands, frequent stumbling, drowsiness, and inability to get up after resting. Victims of hypothermia must be treated immediately by removing them from exposure to the elements, replacing wet clothes with dry ones, and giving them warm, non-alcoholic drinks. Seek emergency facilities as soon as possible.

To prevent hypothermia:

  1. Put on rain gear before it starts to rain or snow.
  2. Put on additional clothes before starting to shiver.
  3. Seek shelter immediately if conditions become severe.


Hyperthermia is a condition of increased body temperature caused by exposure to excessive heat. Contributing factors are physical exertion, clothing, humidity, lack of air movement, and temperature, but the most important factor is body hydration. The normal body requirement for fluids in temperate regions is 2 1/2 quarts per day; desert conditions require more fluid. Early warning symptoms of hyperthermia are chilling, a throbbing pressure in the head, unsteadiness, dizziness, nausea, dry skin (either hot and red or cool and pale), rapid pulse, and muscle pains and spasms.

Persons suffering from hyperthermia should seek medical attention immediately. First aid involves cooling down and rehydrating.

To avoid hyperthermia:

  1. Drink water in moderate amounts on a scheduled basis---do not wait until you are thirsty.
  2. Avoid alcohol, caffeine, and soda---these liquids are not water substitutes.
  3. Wear lightweight clothing and a wide-brimmed hat.
  4. Schedule activities that require the most exertion in early morning or late afternoon, if possible, and not when air temperature is at its highest.
Sun exposure can have painful and dangerous short-term and long-term effects. Regardless of the region in which you are working, take the proper precautions to protect your skin and eyes from excessive sun exposure.

To prevent excessive sun exposure:

  1. Wear sunscreen on all exposed skin to avoid burning and skin cancer.
  2. Wear sunglasses with polarized lenses to protect eyes, reduce glare, and improve vision, especially when working on water or snow.

9.8.2 THUNDERSTORMS, TORNADOES, AND HURRICANES

Thunderstorms, which can be accompanied by hail, are common throughout the United States. Some are predicted by weather forecasters. Others can move into an area with almost no advance warning. Watch the sky for signs of thunderstorms, and seek shelter before the weather deteriorates. Lightning is extremely dangerous and should be respected.

To protect yourself during thunderstorms, heed the following advice from Lockhart (1988):

-- Seek shelter inside a vehicle or building; keep away from open doors and windows, plugged in appliances, and metal. Avoid contact with metal objects in a vehicle.

-- Do not use a telephone.

-- If outside, do not congregate. In case of a lightning strike, someone must be able to begin revival techniques immediately, such as cardiopulmonary resuscitation (CPR).

-- Put on rubber boots or rubber-soled shoes.

-- Do not work on electrical lines, pipes, cableways, or steel structures.

-- Do not use metal objects such as wading rods, bridge cranes, and well-logging equipment.

-- If caught in the open, crouch down low, but do not lie flat on the ground.

-- Avoid standing near isolated trees.

-- Avoid working on streams and lakes.

-- Seek lower elevations such as valleys or canyons---avoid being on peaks or ridges.

-- If you feel your hair standing on end and your skin tingling, this is a sign that lightning might be about to strike---crouch immediately (feet together, hands on knees).

Tornadoes sometimes accompany thunderstorms. Tornadoes are violently rotating columns of air that descend from the clouds in a funnel formation. A weather channel or weather-band radio will sometimes provide advance warning of possible tornadoes.

To protect yourself during a tornado, heed the following advice from Lockhart (1988):

-- Seek shelter immediately if there is a sudden, violent change in weather involving wind, rain, hail, or funnel-shaped clouds.

-- Avoid occupying vehicles or mobile homes.

-- If you are caught outside, find a ravine, ditch, or culvert and lie flat.

-- If inside, go to the basement or lowest interior reinforced part of the structure, such as a closet or bathroom. Stay away from windows.

Hurricanes are severe tropical cyclones with winds exceeding 74 miles per hour, and also can contain heavy rain. Stay informed as to the projected path of an approaching hurricane. Sampling activities should not be conducted until the hurricane has moved out of the area.

9.8.3 FLOODS

Rain can fall at a rate of several inches per hour and rapidly create dangerous flash flood conditions, either in the area where you are working or several miles away. Weather forecasts will be helpful in planning your activities accordingly to ensure your safety. Maintain an updated copy of your district floodplan. Always be aware of rapidly rising stages in rivers and creeks. Beware of dry creekbeds that can become raging rivers in a short period of time.

9.8.4 EARTHQUAKES

Although earthquakes occur more frequently in tectonically active areas, an earthquake can occur anywhere and without warning.

-- Do not panic and run during an earthquake. The greatest danger is from falling objects and walls (including rock formations). If possible, take cover under a solid structure, such as a table, to protect yourself from falling objects until the shaking stops. If you are out in the open, sit down to avoid losing your balance.

-- If an earthquake occurs while driving, slow down and pull over to the side of the road, avoiding overhead structures such as bridges and signs. If on a bridge, try to drive onto solid ground.

9.8.5 FIRE

Fire can spread out of control rapidly--call 911 if you notice a brush fire or other type of threatening fire or smoke. Working inside your field vehicle or outside at your field site requires fire prevention measures. Do not smoke. Keep matches stored in a metal container. Keep fire extinguishers visible and accessible.

-- Know how to operate fire extinguishers.

-- Know the type of fire for which an extinguisher is designed (extinguishers are different for ordinary combustibles, flammable liquids, and electrical equipment).

-- Never point an extinguisher at a person's face.

-- Recharge fire extinguishers according to the schedule provided with the extinguisher.

9.8.6 SNOW AND ICE

Snow and ice are dynamic mediums that change quickly in structure and strength. Snow and ice can accumulate rapidly, hiding hazards, and creating slippery conditions. Heavy snowfall (white-outs) can be disorienting and can produce avalanche conditions in steep terrain. Working on ice requires experience, training, and knowledge of the water body over which the ice has formed. Wear layers of appropriate clothing and work in teams. Refer to USGS Handbook 445-1-H, chapters 14 and 15, for detailed information.

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