It's the eve of the social season in Washington, and this year look out for an explosion of Big Hair.

You know, the hairstyle that's fluffy and wispy -- and somehow stands a good four inches high. Some call it the "Power Helmet" because it resembles football headgear, and because it's often found on Washington's elite. To whip up this sort of do is not an easy task, either. On the list of ingredients: an iron will, a sturdy-but-reliable rattail comb and generous helpings of various over-the-counter chemical solutions.

"It's funny," said a White House aide. "When we show people the press briefing room here, they don't ask about Sam Donaldson. They ask about Lesley Stahl's hair."

Nancy Reagan had, for a while, the highest Big Hair profile. In fact, as First Lady, she was the honorary chairwoman of the Doll Head Club. Effi Barry has since stepped in and is leading the sorority brilliantly. The only entrance requirement is to be smaller than a Size 6 and yet support Size 12 hair.

There's a problem, though. The center of gravity is so high that Big Hair wearers must approach sharp turns with the utmost caution.

Many thought, many actually believed, that when Nancy Reagan left town, Big Hair would disappear.

Wrong.

It's gotten Bigger.

Patrons of theaters, nightclubs and sporting events live in fear of Big Hair. With some events, like concerts, visibility is not absolutely necessary. However, if you've paid $45 for tickets to see "Shogun, the Musical," take heed: Big Hair may be looming about the theater.

This month's Vogue is full of pictures of lithe, cavorting creatures with voluminous tresses. For these young ladies, however, it's just a passing fancy, not a lifetime philosophy. Which, in turn, proves yet another Washington hypothesis: If you wear it long enough, it's bound to come back in style.