Flash floods hit several cities and towns south of Boston Thursday morning as historic rain brought traffic to a crawl and clogged streets and highways during rush hour.With rain coming down so fast,

Boston, Quincy, Brockton, and other South Shore communities are under a flood watch until 9 a.m., according to the National Weather Service.

Several Massachusetts communities south of Boston received as much as over 5 inches of rain, with flooding closing several streets and parts of Interstate 93.