Snow and hail form when water condenses and freezes in the atmosphere, falling as precipitation. Snow begins as water droplets that freeze and fall, while hail starts as rain that strong updrafts carry into extremely cold areas high in storms. During snow and hail storms, it is safest to find shelter inside and stay away from windows, wearing layers if going outside. The largest recorded hailstone measured over 20 centimeters wide and weighed nearly 1 kilogram.