Snow fell over most of the state yesterday, causing travel problems in some areas. National Weather Service meteorologist Marc Russell says cold air settled over the state on Saturday. Russell says a low pressure moved out of the southern plains and parked over Missouri, so the combination of cold air and a low pressure cell prompted the heavy snowfall. Not all of the state, though, was affected. Russell says just a few flurries and cloudy weather is all that blanketed the northern tiers of counties. Other areas, though, got a lot of white stuff.Russell says it appears up to 10 inches fell around Ottumwa.