EXETER — While Yawgoo Valley Ski Area and Sports Park can make its own snow when temperatures are below freezing, snowstorms really draw the skiers and snowboarders to Rhode Island's only downhill skiing spot. When a weekend snowstorm blanketed Rhode Island on Jan. 7 and 8, attendance at Yawgoo spiked. But since the snow has melted and the snow-free weather has fluctuated from mild to cold and dry, business has fallen off.