Hurricane Harvey could be the costliest natural disaster in US history - here's how we'll know the true cost

It will take several months to work out the full impact of Hurricane Harvey on the US economy.

So far, the consensus is that it won't cause that big of a hit to the overall economy's growth, although its personal impact already is and will continue to be far greater.

"We expect the effects of Harvey to be substantial and lasting," UBS economists said in a note. They added that it's difficult to forecast the full impact, even by comparing this to previous hurricanes, because each one is unique.

Here's how economists are calculating its impact: