• Freezing rain or freezing drizzle is forecast when expected rain is likely to freeze as soon as it strikes the ground, putting a coating of ice on roads and walkways. If a substantial layer of ice is expected to accumulate from the freezing rain, a winter storm warning is issued.
• Sleet is small particles of ice, usually mixed with rain. If enough sleet accumulates on the ground, it will make the roads slippery.
• Travelers' advisories are issued when ice and snow are expected to hinder travel, but not seriously enough to require warnings.

EXTREME COLD

Your body, like that of any warm-blooded creature, strives to keep its temperature close to 98.6 degrees F. When the body's thermostat senses that it's becoming too cold, it tries to warm up by constricting blood vessels near the skin. This reduces the amount of blood flowing near the skin, so the blood loses less heat to the air. Shivering begins and that also warms the body. The two key dangers of becoming too cold are hypothermia and frostbite.

Frostbite. If skin becomes cold enough, it can actually freeze. When that happens, ice crystals form and damage tissue. Ears, nose, hands and feet are the most vulnerable. The defense is to be aware of the danger when it's bitterly cold, especially when the wind is blowing. Mittens, hats, a warm covering for the face and warm, dry socks can protect you from frostbite.

Hypothermia. When core body temperature drops below 95 degrees F, a person becomes confused and disoriented. At first shivering is violent; but as the temperature falls, shivering decreases. The result can be unconsciousness and possibly death. Bitter cold isn't necessary for hypothermia. People who are very old or very young are more vulnerable because the body is less able to regulate its temperature. A key defense is to wear wool, not cotton, clothing. When cotton gets wet, it draws heat away from the body. Wool continues to insulate even when it's wet.