These are not really short domain names.
Nevertheless, IMO, considering the topic at hand, I would imagine that ORG has a stronger EndUser value than the COM (just because most NGOs use ORG) for disaster relief domain names; thus, your potential buyers for disaster relief COMs are going to be fellow domainers and those wanting to use the bleed-over, type-in traffic from the ORG. That means the value of these type of names is going to be based on how high the damage is and how great the need for relief is. KatrinaRelief.com would be worth more than CindyRelief.com (also a hurricane from 2005), obviously, because the amount of people hurt by the storm was much greater. More people will need relief and more people will want to give relief = higher traffic potential.
Therefore, the value of one of these names is going to be based on whether or not you get lucky and register the name of a storm that wipes out a large area of populated land. The large the destruction, the greater the value.
Another factor would be whether or not the name is on the rotating list of tropical storms.
Here is the official list of names until 2013 organized by region
http://www.nhc.noaa.gov/aboutnames.shtml#atl
You might want check which months have had the most violent storms and which area of the world those storms were located. This is definitely an area where research into the subject will help you pick your investments more wisely.
