Severe weather prompts evacuations at 4th of July events

Severe weather disrupted celebrations of America's 250th anniversary of independence Saturday in several East Coast cities, including Washington, where storms prompted a roughly two-hour evacuation of the National Mall.

Anticipation for the milestone holiday has been building for much of the year, serving as an opportunity for Americans to reflect on their complicated history as onetime colonists of an empire who became a superpower of their own.

The disruption was particularly acute in Washington, where signs at the Great American State Fair posted an alert shortly after 7:00pm encouraging participants to leave the area.

Crowds gathered in museums, subway stations and federal buildings near the Mall. At the Ronald Reagan Building and International Trade Center they waited in chairs and sat on the floor to cool off in the air conditioning.