Winter weather offers a host of opportunities for outdoor fun, but cold temperatures combined with alcohol can make even walking across the Green dangerous. Students who drink alcohol in the winter put themselves at greater risk of injury, according to Lynn McDonald, program manager of the Dartmouth-Hitchcock Medical Center's Injury Prevention Center. Alcohol causes two problems, McDonald said: it decreases judgment and self control and worsens coordination and balance. When combined with poor weather conditions, decreased control and coordination is especially dangerous, she said. "Alcohol has a big impact on one's ability to judge distance and make good decisions," McDonald said. These decreased abilities can affect students who want to "have fun and be safe while skiing, skating, and playing hockey," she said. Alcohol also becomes dangerous when it leads outdoor enthusiasts to have a "false sense of bravado," McDonald said. People who are "normally cautious in their winter sports choices tend to think they can do more than they regularly would," she said. Alcohol can lead to people skiing faster than usual, skiing more difficult terrain or possibly skiing in off-limit areas, McDonald said. But one of the greatest dangers associated with drinking during winter months occurs when drinkers do not wear clothes appropriate for the weather. Alcohol causes blood vessels to widen, allowing more blood to flow through them, McDonald said.