HONOLULU - The National Weather Service has issued a blizzard warning for mountains on Hawaii's Big Island, saying wind gusts of above 100 mph (160 kph) and 12 inches (30.4 centimeters) or more of snow were possible.The warning in effect through Sunday morning for Big Island summits said "travel should be restricted to emergencies only" and those who must travel should have a winter survival kit.Blizzard warnings for Hawaii are rare, but not unheard of.