Hurricane Harvey will be the most costly natural disaster in US history, predicts AccuWeather.

It believes the impact on the country’s gross domestic product will be $190 million, and as a result will force the Federal Reserve to postpone the next increase in interest rates.

Harvey, which made landfall as a Category 4 hurricane near Rockport, Texas last weekend, has brought catastrophic flooding to a wide area, including Houston, the fourth largest city in the US.

More than 20 people have died as a result of the storm and subsequent flooding.

Joel Myers, president of US-based weather forecasting company AccuWeather, said: “This is the costliest and worst natural disaster in American history. AccuWeather has raised its estimate of the impact to the nation’s gross national product, or GDP, to $190 billion or a full one per cent, which exceeds totals of economic impact of Katrina and Sandy combined.

“The GDP is $19 trillion currently. Business leaders and the Federal Reserve, major banks, insurance companies, etc, should begin to factor in the negative impact this catastrophe will have on business, corporate earnings and employment.

“The disaster is just beginning in certain areas. Parts of Houston will be uninhabitable for weeks and possibly months due to water damage, mould, disease-ridden water and all that will follow this 1,000-year flood.”

Earlier this week, catastrophe modelling firm RMS estimated economic losses from the storm could be as high as $70 billion to $90 billion.

Another modelling firm Air Worldwide has estimated insured property losses from wind and storm surge to be in the region of $1.2 billion to $3 billion.