IAGC LAND GEOPHYSICAL SAFETY MANUAL Edition 9 ... - CGISS

3.17 Cold Weather Operations and SurvivalOne of the most important lessons to be learned is that, in all cases, extreme colddictates that additional time is required to complete a job assignment. Such time shouldalways be allowed in the planning phase.3.17.1 GeneralAll environmental problems in arctic or cold regions are important and none can beignored. The most persistent and most dangerous is that of extremely low temperaturesor low wind-chill.The primary problem in cold weather is exposure to lower temperatures ranging from 5to 10°C (40 to 50°F) and above zero to 40 to 45°C (40 to 50°F) below. In calm air, 4°C(40°F) above zero might not seem very cold, but in a relatively gentle 16 km (10 mph)wind, the equivalent chill temperature drops below freezing.Maximum wind speed occurs during periods of seasonal transition and changingtemperatures. Winds above 160 km/hr (100 miles/hr) during such periods have beenrecorded. For the full impact of wind chill, you can note on the wind-chill chart thatfollows that a 16 km (10 Mph) wind with a -21°C (-5°F) calm air temperature producesan equivalent chill of -32°C (-25°F), at which exposed flesh may freeze within oneminute.The adverse effect of cold on man is to produce a condition called hypothermia, which isthe lowering of body temperature due to loss of heat at a rate faster than the body canproduce it. Normal, body temperature is 37°C (98.6°F). When the body temperature fallsbelow 34°C, (94°F), the patient may become disoriented and lapse into a coma. Heartfailure and death can result if body temperature falls below 31 to 32°C (88 to 90°F).Frostbite (a cold injury caused by freezing of the body tissues or body part) can occurwithout hypothermia when extremities do not receive sufficient heat from the centralbody due to restricted blood circulation or inadequate insulation. Both conditions(frostbite and hypothermia) may occur at the same time if the body is exposed tosubfreezing temperatures. Whenever a patient is treated to thaw any portion of thebody, care must be exercised to prevent the possibility of refreezing.Wind Chill ChartHypothermia can occur from exposure to temperatures above freezing in instances suchas immersion in cold water, exposure to wind (wind chill), physical exhaustion andinsufficient food.The use of alcohol in a cold environment is extremely dangerous. It causes dilation ofthe blood vessels, permitting a rapid loss of body heat and thus, increasing the risk ofhypothermia.Related cold injuries include trench foot (a thermal injury resulting from exposure to cold,short of freezing, in a damp or wet environment), immersion foot (an injury resemblingtrench foot and caused by prolonged immersion of the extremities in water) and theeffect of total immersion in near freezing water. In this last case, immersion for only afew minutes will cause total body cooling with a marked drop in inner bodyPage 57 of 136