Depends on the situation.
If there is a "disaster" which is localized and won't affect them (in their ivory towers), then, yes much of it would go toward helping the citizens. (Eg. tornatoes, floods, huricanes, earth quakes, etc.) BUT, if they had any reason to believe that THEY would be affected - forget it! We would be SOL!
(That would be in addition to what they have stockpiled already - probably at our expense. There is a LOT of room in those mansions to store stuff!)
They would have the power to order that additional supplies be diverted to a location of their choice, you know. (To "protect" it "for" the people, don't you know.)
Gov't had 48 Million MREs to distribute to folks in the aftermath of Hurricane Katrina. When the IN Nat'l Guard got there (about Day 8) demand in Mississippi had fallen off; the one day I flew a general resupply mission, most people were asking for water and diapers.
I've read somewhere that most major cities have only a 3-day supply of food in warehouses. If the food distribution system (e.g. highway system) is disrupted, food supplies will rapidly disappear. The Federal Emergency Plan calls for getting the first emergency aid into a disaster area in 72 hours. To air a pet peeve of mine, for all the Crap FEMA (& Bush) took for FEMA's response to Katrina, there were 11 US&R TFs staged in the northern part of Louisiana, East Texas, and northern Mississippi at least 24 hours before the hurricane reached land. FEMA also had the aforementioned 48 million MREs and some unbelievable amount of water PRE-STAGED. The delay in getting to the affected areas was primarily because Louisiana wouldn't give FEMA permission to enter the state (or didn't request a Federal Disaster Declaration), and the Teams had to literally cut their way down to the coast past downed trees and power lines.
Except if the disaster is nation-wide, FEMA has a ton of pre-staged resources to assist, but it does take time to get them organized for deployment (the last I heard a FEMA Urban Search & Rescue Task Force has a maximum of 8 hours to gather, perform required pre-deployment paperwork and medical screening, load 3 - 5 semi trailers with search, rescue and logistics supplies, arrange for personnel transport, brief, and get on the road. Add in travel time, then add in time for staging, briefing, handing out assignments, and fleshing out the Operations, Planning, Rescue, and Logistics plans.
It all takes time. Even locally, in Indianapolis where, unlike most of the rest of the state, there are plentiful emergency response and public/private resources, it can take a full day to ramp up from the initial response to a disaster. Everyone would be well advised to be able to last at least a week without food or tap water.
3 days worth of food is what any normal family should have in their cabinet anyway in canned food alone. I can see water being a little more of a pain but a few 5 gallon jugs should cover that need as well.