The tundra has a very extreme climate. The intense cold presents many problems if you are not prepared. In any situation where extreme cold is present, hypothermia is a risk you take. Hypothermia is the lowering of the body's core temperature. There are two types of hypothermia, acute and chronic.
Acute hypothermia is the rapid lowering of the body's core temperature.
Chronic hypothermia is the slow lowering of the body's core temperature. If the temperature drop occurs in less than four hours it is acute, otherwise it is chronic. Acute hypothermia is also called immersion hypothermia and typically occurs when a person is in cold water. It is important to note the difference between the two since treatment will be different. Hypothermia is considered severe when the body's core temperature drops below 90 degrees F, and mild from normal body temperature to 90 degrees F. Frostbite is another problem in areas of extreme cold.