It’s a term that comes from military parlance.
Standing armies are those that are currently active.
Standing up an army/force means activating or creating a force.
Standing down is the reverse...which has also come to mean relax from a more active state.
As with a lot of military terms this one has made it’s way into government parlance, because of the similar type of activities taking place in a bureacracy or other civilian force that is on call... in this case FEMA
Thanks for that info.
I was former military and totally familiar with “stand down”, but not with “stand up” as they’ve been using it. (Still grates on my ears.)