Imagine. The news media are onto your crisis. And so are the social media - which can be an even bigger challenge. Why? Because the social media are much faster and much freer with exaggerations and outright fiction. Social media can treat your crisis the way a pack of dogs treats a rabbit.
How to go onto the front foot
You could send them an internal letter worded something like this:
As you may have heard, we're dealing with a difficult situation right now. Here's what we're releasing to the media at this stage. Please feel free to post the same facts on your own social platforms - in your own words. But to keep everything accurate, please don't add any other facts (no matter where you got them) without checking with me first. Please also avoid any speculation or comments which might fuel distorted messages on the net.
Yesterday, a fire broke out in... (etc)
We don't yet know the cause... (etc)
Keep your staff current with media key messages
And keep updating staff with your updated key messages for the media. That's a good thing to do anyway - quite apart from your purpose with the social media.
Why not ignore social media? Because they can do real damage to your organisation and your staff are going to use Facebook and Twitter anyway. You might as well sow the seeds of truth.
There are other things you can do to cope with the force of social media, but that's another story.