Branchport, N.Y. — Winter finally came down hard on New York's Finger Lakes this month with single-digit temperatures at dawn and snow blowing over the rolling vineyards.

The wait was over for an ice wine harvest.

The sweet wine that has become a specialty for a number of vineyards dotting upstate New York hillsides — albeit one dependent on the increasingly noticeable vagaries of winter.

Grapes are left on the vine through at least though the fall. When temperatures get cold enough to freeze the water in the grapes, winemakers pounce. The slushy grapes yield a more concentrated juice. The resulting wine is sweeter, heavier and often pricier.

Ice wine is big in Canada, but it remains a small niche in the multi-billion U.S. wine industry, confined mostly to upstate New York, Ohio and Michigan.