If...
...I had been planning the evacuation I would have created at least two and possibly three refugee target destination states & cities for exactly the reasons you mention. With this many refugees they really should be spread out.
The police forces, medical workers will be very busy.
Possibly, other Texas cities should start moving victims so as not to burden Houston too much.
The great state of Texas will get a chance to show just how big it really is.
Take care REB.