People across campus bundled up last week as temperatures bottomed out to the single digits and below. In fact, with the wind chill factor some days reached 20 below. With the falling thermometer came a rise in severe cases of frostbite seen at the U-M Trauma Burn Center, prompting medical professionals to remind those who must be outside that as little as 20 minutes of exposure can cause damage to the skin and underlying tissue. The most commonly affected areas are ears, nose, cheeks, hands and feet. Temperatures are expected to be a little warmer this week, but health experts say it still will be a week to dress warmly, wear layers and avoid prolonged exposure to the elements. (Photo by Scott Galvin, U-M Photo Services)