Apparently 911 service in the entire state of Massachusetts was down or significantly degraded today (it's back up now).

Reminder: because of the way 911 works, it's subject to central failures that can prevent calls from being correctly routed.

Most police/fire/EMS emergency call centers have a regular (dial-able 10 digit) number in addition to 911. It's worth finding out that number NOW and programming it in your phone's contacts.