Um... You might want to think this through a bit more.
You tripped over the reason without realizing it when you said, "especially when it occurs in a remote area in a third world country when it is difficult to make a phone call on a good day", but you failed to understand it.
The reason that fatality counts rise hour by hour and day by day after these kinds of disasters is precisely *because* the counts from more remote areas aren't available immediately, and begin to trickle in one or more days after the initial disaster, continually raising the totals.
In the first hours, tallies of, say, 2000 will come in from the more accessible areas. Later, another 500 are reported found dead in the first areas to be reached by rescuers. Then another 500 after a few more hours as even more remote places are checked and word gets back to the central headquarters, etc.
There's absolutely nothing suspicious about how "counts multiply within days of a natural disaster", and there's no reason it should "amaze" you -- it's to be *expected*.
The body count is rising because they are still finding bodies and they will continue to find them for days and weeks to come. Were you suggesting by being "amazed" that something sinister is going on with the reporting and the counting?
I heard on the news today that another body had been found in New Orleans.