How to Prevent: Cold temperatures, wind, and excessive combing can create a buildup of negative ions on the hair shafts, which causes individual strands to repel one another, explains Roberta J. Hawk, a dermatologist in Billings, Montana. In a word: static. “Use a mild shampoo for dry hair, and always use conditioner, which gets rid of negative ions,” she says. RS Pick: Redken Smooth Down Shampoo ($8.50) and Conditioner ($10, 800-733-5368 for store locations).

How to Treat: River Lloyd, a hairstylist at the Peter Coppola Salon in New York City, suggests spraying Static Guard ($3.50 at drugstores) onto a hairbrush and brushing it through hair. “It always works,” he says.

When to See a Professional: Flyaway hair accompanied by an itchy, flaky scalp indicates dandruff. If the condition doesn’t improve after you use an antidandruff shampoo like Head & Shoulders Classic Clean ($4.50 at drugstores) for two weeks, see a dermatologist.