A Guide to Safe Field Operations
U.S. Geological Survey Open-File Report 95-777

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In the Field

Weather

Normal comfort temperature range for man is between 60 and 90xfb F. Beyond these limits various precautions become necessary, depending on tolerance and adaptation to extremes. Most cases of hypothermia (condition of reduced body temperature that results in rapid mental and physical collapse) develop in air temperatures between 30 and 50xfb F. Hypothermia is aggravated by wet clothes, wind, hunger, and exhaustion. The best way to avoid hypothermia is to take more clothes than will be needed and to dress appropriately with layers of clothing and adequate headgear. Layers of clothing can be removed or added as the temperature changes. Prepare yourself for working in cold environments by:

Acclimating yourself to conditions by scheduling moderate exercise outdoors with frequent breaks in sheltered areas.
Carrying a sleeping bag, blanket, and a small stock of food in the field vehicle.
Carrying replacement clothing, particularly for items that may become wet.
Carrying good rain gear and using it before clothes get wet.
Being aware of the conditions that lead to hypothermia.
Leaving a detailed travel plan before venturing into remote or untraveled territory.
Keeping informed of local weather conditions. Don't get caught in severe weather.
Learning and practicing cold weather survival techniques.

The opposite physiological condition is hyperthermia, in which heat in excessive amounts can create a life threatening situation. Temperature, humidity, and physical exertion all contribute to this condition, but body hydration is the most important factor. Prepare yourself for working in hot environments by:

Wearing light-weight, light-colored clothing.
Wearing a wide-brimmed hat.
Acclimating yourself to conditions by scheduling moderate exercise in the direct sunlight with frequent breaks in a shaded area.
Drinking a moderate amount of water on a regular schedule. Normal water requirements in temperate regions is about 2-1/2 quarts per day; desert conditions will require more.
Scheduling the most physically demanding activities in the early morning and late evening to avoid the heat of midday.
Being aware of the warning symptoms that lead to heat exhaustion, heat cramp and heat stroke induced by heat.

Sun exposure can cause first and second-degree burns, and you should be aware of your susceptibility to burning. It is recommended that you wear protective clothing and cover exposed skin with sunscreen. Remember that the intensity of radiation is greater at high elevations and exposure is increased where light is both direct and reflected from light surfaces, such as snow and sandy areas.

Thunderstorms are a serious danger while working in the field. Lightning is the storm's worst killer, but the intense rains, hailstorms, and wind associated with these storms can create dangerous conditions. Frequent monitoring of weather reports is important for scheduling your activities to avoid extreme weather conditions. While working in the field, keep an eye on the weather and notice whether towering cumulus clouds that mark the location of thunderstorms are approaching your work area. The safest place to be during a thunderstorm is in the field vehicle with doors and windows closed. General guidelines for avoiding dangerous conditions during thunderstorms are:

Stop making wading, bridge, or cableway measurements and seek shelter in a structure or your vehicle.
Do not use the telephone or work on electrical lines or steel structures, such as bridges or cableways, because a lightning strike some distance away could affect you.
If you are on a ridge or peak, get down to a lower elevation, preferably a level bench.
Avoid isolated trees; seek shelter in dense stands or clumps of young trees.
Sit on your feet in a crouched position or sit on some insulating material, such as wood, rubberized material, or a wool shirt.
Be aware of flash floods, avoid stream crossings, and move vehicle and equipment to higher ground.
Seek shelter from high winds and tornadoes; avoid high trees and find a sheltered draw. If you feel a sudden violent wind or sight a funnel-shaped cloud, seek shelter immediately by lying flat in a depression, ditch, or culvert.

Additional information on thunderstorms and lightning can be found in National Weather Service NOAA/PA 83001 (June 1985).

Terrain

Working in and around streams and rivers will subject you to many conditions in which the local terrain may cause slips and falls that could result in serious injury to you and your coworkers. You can't avoid all potential dangers, but you can minimize the risk of accidents by considering the following guidelines.

Wear shoes or boots that provide good arch and ankle support instead of low-cut sneakers.
Inspect the area before beginning work and locate gopher, muskrat, or other holes; isolated rocks and boulders; fallen logs; loose and slippery rocks; and other obstacles.
Select a level work area and remove debris that could cause you to trip and fall. It may be necessary to cut tall vegetation to be sure the site is free of obstacles. Carry a machete in a sheath to cut vegetation instead of plowing through dense vegetation or taking another route over treacherous terrain to avoid dense vegetation.
If you must travel some distance from your vehicle, avoid taking shortcuts across treacherous terrain; consider the time lost by an accident than by going the longer and safer way around.
Avoid steep slopes with loose rocks and boulders that could come loose and tumble down the slope.
Select sites for wading discharge measurements very carefully; keep in mind both the hydraulic characteristics required and safe conditions for accessing and wading the stream.
Traverse streams carefully and use a wading rod or stout stick to probe the bottom in advance. If you find deep holes or a highly irregular bottom, look for another section.
Be careful while walking on rocks and boulders in streams; they are usually very slippery. Consider wearing some type of sole gripper to give you additional traction.
Wear a PFD when working in and around streams, rivers, and lakes.

Animals

There are numerous animals that may represent a risk. Snakes and insects are probably the most common nuisances that you will face, but other reptiles and domestic and wild animals can cause serious injury, illnesses, and fatalities.

There are four snakes in the United States that are poisonous and should be avoided: rattlesnakes, cottonmouth, copperhead, and coral snakes. There are numerous species of rattlesnakes throughout the U.S. Cottonmouths and coral snakes generally range from the Carolinas through Florida, westward to Texas, and up the Mississippi Valley. Copperheads are found in much of the eastern U.S. and parts of Missouri, Arkansas, Oklahoma, and Texas. The most effective defense against snakes is to avoid being bitten. The following precautions should be taken to minimize the risk of snakes while working in the field:

Familiarize yourself with the description and habits of all poisonous snakes indigenous to the work area.
Wear protective clothing, including boots and knee-high or full-length leggings in prime snake terrain.
Be observant and look before you step or reach for something.
Use existing trails and use a walking stick to clear vegetation ahead of you. Don't step over logs without looking on the other side first.
Don't climb among rocks where you have to reach above your level of sight for a handhold.
Don't pick up rocks or other objects that might conceal a snake. Turn the object toward you with a stick or shovel. This could shield you from being bitten.

Insects generally are a nuisance while working in the field, but they can be dangerous depending on the type of insect and your reaction to their sting or bite. Stinging insects, which include honey bees, killer bees, wasps, yellow jackets, hornets, and ants, are painful and can be dangerous to individuals that are allergic to the venom. The yellow jacket and hornet are the most dangerous because they are aggressive and can inflict multiple stings. You may be allergic to venom or you may develop an allergy with each new attack. Reactions can range from fever, light-headedness, hives, and painful swelling to a sudden drop in blood pressure and breathing difficulties. Biting insects, such as mosquitoes, chiggers, ticks, and various flies, are generally of less immediate hazard than stinging insects, but they may be carriers of disease. Ticks are the major carrier of disease in the U.S., transmitting Rocky Mountain spotted fever, Colorado tick fever, tularaemia, and relapsing fever or tick paralysis, and Deer ticks-Lyme disease.

Members of the spider family are another concern in both the field and office in certain parts of the country. Those of most concern are the black widow and brown recluse spiders and the scorpion. The spiders range widely in the temperate region and tend to seek dark hiding places. Scorpions range from the Gulf States to California and north into the dry areas of the west. Scorpions tend to seek shelter under bark, litter, sand, or rocks and may crawl into shoes, gloves, etc.

Keep in mind that there is just as much danger of falling off ladders and cableway platforms from trying to avoid bee stings as from the actual sting.

Common precautions against members of the spider family and insect bites and stings are:

Wear clothing that makes access to the skin difficult.
Avoid tramping through heavy vegetation if another choice is available.
Be observant of wasp nests, hornet hives, and ant hills.
Use insect repellants on exposed skin and at openings in your clothing. Spraying pants cuffs and socks is a good preventative for chigger bites.
In the case of ticks, inspect clothing and exposed skin periodically during the day, and disrobe completely and inspect your skin at the end of the day.
Obtain immunization in advance if you are allergic to stings or will be working in an area with infestations of disease carrying insects.
Carry appropriate medication for allergic reactions and inform your coworkers about how to administer it.
Watch out for characteristic dense webs of spiders.
Avoid reaching into dark places where you can't see and be careful picking up rocks and clothing that have been lying on the ground.

Other animals may be a dangerous depending on whether you surprise them or represent a threat to their young, food, or territory. Most wild animals will be frightened away at sight, but the more domestic they are and the more familiar they are with humans, the less likely they will run from you. Because of this, dogs probably represent the greatest threat while in the field.

Significant animal threats also come from bears, moose, bulls some domestic livestock. These animals may actually chase people, so don't challenge them. Expect animals to defend their territory. Refer to the discussion of bear behavior by Brew and others (1978). Numerous smaller mammals are likely to be afraid of humans, but don't count on it. For instance, beware of porcupines and skunks that cease to flee and raise their tails vertically. They fight with their tails and the field person may become a target for flying quills or noxious excretions. The following guidelines are recommended to avoid animal attacks while in the field.

Avoid surprising animals by making noise while traversing a trail or open country.
Choose open terrain with good visibility.
Make a wide detour around any animals with young, or over a fresh kill.
Avoid walking in pastures or fields with domestic bulls.
Avoid any animals acting abnormally. Many smaller mammals, including the coyote, fox, badger, raccoon, skunk, and squirrel may bite and transmit rabies.
Carry a walking stick to fend off attacks from domestic dogs.
Watch out for rodent nests. New rodent nests must be noted for future removal.

Poisonous Plants

The most common problem with poisonous plants is the allergic reaction that individuals have to the sap of poison ivy, poison oak, and poison sumac. The sticky sap of each plant can cause an allergic skin reaction of varying intensity depending on the amount of contact and the degree of susceptibility of the individual. The sap can be transferred directly by brushing against or handling the plants and indirectly from tools or clothing and from smoke of burning plants.

Avoid allergic reactions to poisonous plants by:

Learning to identify poisonous plants and avoiding contact.
Wear gloves and protective clothing when contacting plants cannot be avoided.
Remove contaminated clothing as soon as possible and wash immediately to avoid contact by other individuals.
Wash affected skin with abundant soap and water.

Some plants are poisonous to eat, and it is advisable not to eat any wild plants unless you have knowledge of safe plants and plant parts.

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A Guide to Safe Field Operations
U.S. Geological Survey Open-File Report 95-777

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