FOX has been reporting that due to the high winds they could not use helicopters to evacuate the wounded to trauma centers. Many of the wounded had to be taken in police cars.
So I agree with you, many of these fatalities are most likely due to the fact that immediate emergency care was unavailable. Horrific events today.
You can expect about 20% will be killed almost immediately and nothing can be done to save them. For those still alive, all you need is BLS for the first half hour to an hour.
Initial emergency care for a gunshot wound consists of direct pressure over the entrance/exit. Bare hand if need be. Nothing special is needed.