Not being able to actually use a shelter during a disaster means that you have wasted precious resources looking for safety and not finding it. Recent major disasters such as Katrina and Sandy have shown how little attention was paid to the needs of people with disabilities. Portlight (Sponsors of the #ruready initiative) developed a very useful set of guidelines called TRUE:
http://http//www.portlight.org/true-shelter-accessibility/
"Disasters are always inclusive. Response and recovery are not, unless we plan for it!"
June Isaacson Kailes, Disability Policy Consultant
June has a nice pretty comprehensive set of resources at her consulting site on many issues of disaster support for people with disabilities:
http://http//www.jik.com/disaster-plan.html