Hopefully we have, as communications engineers about handling emergencies such as 9/11 (for the US) and 7/7 (for the UK), learnt some important lessons about handling large scale emergencies.
Trunked communications for the emergency services work well normally, but in the case of a large scale incident the sheer number of users can overwhelm the system, and the loss of power for nodes or failure of links can also cause chaos. Some trunked links are co-sited with cellular, but it does depend on both the capacity and of any standby capacity. This of course assumes an incident in an area with good coverage.
There is still a need for direct communications, and a good degree of resiliance. With the knowledge that a lot of services have long scrapped their non-trunked gear, are they are more exposed?
Cellular systems are only built with a limited capacity, if you have an event, such as a festival, then the phone system may not even be available to the public to make an emergency call, simply as the cells are swamped. You try and send an SMS just after New Year has started. Where they have been incidents, particularly in National Parks (in the UK - with a high population density generally, but these areas are of low population) then cell phones often don't work, and some emergency services such as Mountain Rescue still rely on their own communications. There's pressure to sell off these commercial frequencies for such as 4G use, but then that assumes that coverage will be provided or could be in the more remote areas, given such as cost, planning restriction and practicality of siting links in locations generally without vehicular access.
I do know that one of the UK trunked operator had disabled the point-point functionality in their handsets, so all communication needs to go through a node, which does knock back one layer of resiliance. We suppose for the forseeable future we the Amateurs will be sitting on standy, unless they do come up with some workaround. In the meantime, there will always the idea that we'll still be called out to fill in the gaps.
