It's probably similar to near-by Montgomery County, Maryland. In Mo. Co. it means the Emergency Communications Center is experiencing very high call volume and/or several working incidents on the fireground channels. More specifically, under "condition red" routine radio traffic is not permitted (e.g., notifying the local utility of wires down, etc.), including routine hospital notifications. In my experience, this has also meant that they were too busy to even pickup the direct line from the police dispatchers. "Condition red" is rare, but usually happens a few times a year during bad thunderstorms.
In Mo. Co. the police and fire/EMS dispatchers are separate but located in the same building. Police dispatchers generally answer 911 calls and transfer them if they're fire/EMS-related. If police dispatchers are busy, then the fire/EMS dispatchers will handle 911 overflow.
-Eric