Just a different perspective - most of my sheltering experience follows house and apartment fires, and by definition if you're burned out of an apartment you aren't homeless, at least not initially. In the flood-related RC shelters I've worked at and managed, we sheltered a few homeless, folks who lived in the woods before a flood, but they were actually the first out of the shelter when the waters receded - going right back to their camps.

The one common denominator among shelter clients is they don't have any other options - no relatives, no friends to stay with. When the event is large enough, even those who might be prepared lose those options, and they end up in a shelter. That's basically why I work shelters - everyone deserves a warm, safe place to sleep, some food to eat, and some dignity in the whole transaction. The fire or flood that has displaced them can be a heavy blow, they don't need other complications weighing on them for a little while. So, make a plan, but things can and will go south on you sometimes.