Special Report: Severe weather affects July Fourth events in D.C., New York and Philadelphia

Severe thunderstorms forced July Fourth events across the East Coast to be evacuated, disrupting celebrations in major cities.
America's 250th anniversary festivities in Washington, D.C., New York City and Philadelphia were impacted.
In D.C., more than 10,000 attendees near the National Mall were told to seek shelter as storms moved in.