Hurricane Harvey could be the costliest natural disaster in U.S. history with a potential price tag of $190 billion, according to a preliminary estimate from private weather firm AccuWeather.

This is equal to the combined cost of Hurricanes Katrina and Sandy, and represents a 1% economic hit to the gross national product, AccuWeather said.

“Parts of Houston, the United States’ fourth largest city, will be uninhabitable for weeks and possibly months due to water damage, mold, disease-ridden water and all that will follow this 1,000-year flood,” said AccuWeather president Joel Myers.

Floodwaters fill the road running through the Lakes On Eldridge North subdivision in the aftermath of Tropical Storm Harvey in Houston.  Brett Coomer, Houston Chronicle via AP.

The Federal Reserve, major banks, insurance companies and other business leaders should begin to factor in the negative impact this catastrophe will have on business, corporate earnings and employment, Myers said.

Weatherwise, the worst is over in and around Houston, though catastrophic and life-threatening flooding from the rain that’s already fallen will continue for the rest of the week, the National Hurricane Center said.

Hurricane Harvey was the first major hurricane to make landfall in the United States since Wilma in 2005, ending a record 12-year period with no hurricanes of Category 3 intensity or higher making landfall in the United States. In a four-day period, many areas received more than 40 inches (1,000 mm) of rain as the system meandered over eastern Texas and adjacent waters, causing catastrophic flooding.

With peak accumulations of 51.88 in (1,318 mm), Harvey is the wettest tropical cyclone on record in the contiguous United States. The resulting floods inundated hundreds of thousands of homes, displaced more than 30,000 people, and prompted more than 13,000 rescues.