This isn't an ordinary heat wave. Many locations could set new all-time March, even April, record highs from the West Coast into the Plains. And this will have one other impact that could linger into summer.

Allergy season doesn’t follow a simple calendar, it begins when plants start releasing pollen, and weather plays a huge role in when that happens and how intense it becomes. Meteorologist Sara Tonks explains how mild winters, warmer temperatures, rain, and even wind can fuel longer, stronger pollen seasons, and why tools like pollen forecasts can help allergy sufferers stay one step ahead.

Decades before radar and tornado warnings, this is still widely considered the nation's single worst tornado event.

The digging out is always the toughest part. Blizzard conditions drove snow into huge piles in Marquette, Michigan. The area received more than 3 feet of snow over Sunday and Monday as Winter Storm Iona blasted through.