13 states from Washington to Illinois are on alert for heavy snow and flooding.

Two storm systems moving out of the West will combine into a Winter Storm in the middle of the country and could bring the biggest snowstorm of the season to parts of Midwest.

Already on Sunday, the northern storm brought damaging winds up to 50 mph in Seattle where trees were reported down on homes, critically injuring a person.

In Colorado, the southern storm brought heavy snow of up to 10 inches that caused accidents on the roads on Sunday.

As these storms move east, 13 states from Washington to Illinois are on alert for heavy snow and flooding.

This morning, the southern storm is already in the Plains and bringing rain ahead of it for most of the South and Mid-Mississippi River. Flooding is also possible in the Plains today as this heavy rain moves through.

To the north, heavy snow is falling in the northern Rockies from Idaho to northern Colorado.

By Tuesday morning, the storms should begin to combine in the Midwest and spread heavy rain all the way to the East Coast.

Heavy snow will also move into the northern Plains from Nebraska to the Dakotas.

On Wednesday morning, the Midwestern storm really strengthens and becomes a powerful winter storm for Iowa, Missouri, Illinois, Wisconsin, Indiana and Michigan.

As this storm moves through the country this week, some areas in the Midwest could see up to a foot of snow. This could be the biggest winter storm for some of this winter season.

Locally, there could be up to a foot of snow not far from Chicago, maybe just north of the city, where the city could see 4 to 8 inches.

To the South, already flooded areas could see more rain this week from this storm and, locally, more than 2 inches of rain is possible.