It's not uncommon for death tolls to rise weeks after a natural disaster has hit.

More than six months after Hurricane Irma's catastrophic rampage across the Caribbean and the southeastern United States, the U.S. National Hurricane Center raised the death toll to 129 — more than twice the amount reported at the end of the storm.

It also took years for Hurricane Katrina's death toll to become fully known. That number is still debated today with figures used by different agencies varying by as much as 600 deaths.

President Donald Trump has questioned Puerto Rico's adjusted death toll from the devastating storm last year and said the number rose "like magic."

Disaster experts say realistic death tolls take time.