Residents of Philadelphia and some surrounding counties are cleaning up and assessing damage after a series of severe storms called microbursts swept through with winds up to 60 or 70 miles per hour. The storms came through Saturday, downing trees and power lines, flooding several streets and even causing at least one building to collapse that left bricks and debris in the street, crushed cars and blocked trolley tracks. City and housing authority officials evacuated at least two apartment buildings that were heavily damaged.