Question:
2nd alarm, 3rd alarm, etcI always hear about x-alarm fires, but what exactly does each alarm mean, and how is it determined?

Answer: Your question appears from time to time, and I'm pleased to be among the first to offer what might be considered a generic response. Lest I be mistaken, I doubt you wanted a vast number of individual answers as to how your question might apply individually to the *many* Fire Departments that stretch from the Aleutian Islands to Zanzibar. While *some* nomenclature is standardized in *many* Fire Departments [emphasis added], especially national systems such as those in Great Britain, such is not always - and dare I say rarely in North America. The quick and dirty answer? In North America, there is no Fire Service standard for the numbering of alarms. As in the rest of society, the Fire Service technology and policies for dispatching, controlling and coordinating the response of Firefighters has steadily evolved but is rarely standardized. In brief and general terms... In most agencies then as now, the first wave of apparatus dispatched to a primary notification of an incident might be considered to be answering "the first alarm". Not all agencies will officially use the term "first alarm", but it is a phrase widely understood by Firefighters in general conversation to specifically include those resources first dispatched to the scene. This sadly however, is where logic or commonality departs. For to properly answer your question, we must be agency specific from this point forward. There is no formal standard for the numbering of alarms in North America, and the systems in place may vary by community or region. In fact, while still nodding to the term "First Alarm" as mentioned above, many progressive Fire Departments stopped the numbering of alarms as a reference and operational tool many decades ago, Back to technology for a moment... Before the days of radio communications and the like, when there was a quick need for additional resources on the fireground, it was common to dispatch fire apparatus in predetermined groups as needed. Hence the most common reference to "2nd, 3rd, 4th, etc. Alarm" - which then as now (where applicable) is generally an agency specific request. Some agencies to this day "strike an additional alarm" *every* time there is an additional request for any type of resource, while in others, the clearly antiquated practice brings a specific and pre-determined group of vehicles and/or personnel (i.e. each additional alarm might mean three engines, an aerial ladder truck and a Chief Officer). Again, there are no standards. What might constitute a "Five Alarm Fire" for one agency might be an "Eighteen Alarm Fire" for another... and a "General Alarm" or "Greater Alarm" for others. Rob, when all is said and done, you do indeed deserve a specific answer to your question. To make it relevant to your daily life, I would encourage you to visit *your* Neighborhood Fire Station and ask how your local Fire Department escalates an incident and coordinates response. I think you will find it intriguing. If you happen to live in Los Angeles, visiting a Fire Station is no more difficult than clicking: http://www.lafd.org/visit.htm