Flash floods hit cities and towns south of Boston Thursday as historic rain brought traffic to a crawl and shut down part of I-93.

A "considerable" flash flood warning has been issued in Boston as heavy, life-threatening rain pounds the city and areas to the south. Two to 4 inches of rain has fallen so far. Rainfall rates are reaching up to 2 inches per hour.

I-93 was essentially a river Thursday morning as torrential downpours dumped up to six inches of rain across eastern Massachusetts. As you probably heard from your phone's alert system screaming at you,