Hurricane Harvey, which has wreaked havoc in Texas, is predicted to be the most costly natural disaster in US history.

The warning came from forecaster AccuWeather as parts of Houston remained under floodwater and oil refineries were shut around the Gulf Coast.

AccuWeather founder and president Joel Myers 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 produce, or GDP, to $190 billion or a full 1%, 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, the United States’ fourth largest city 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.”

Catastrophic flooding will continue in Houston, where the rain has ended, and in Beaumont and Port Arthur, Texas, to Lake Charles, Louisiana, even after the rain comes to an end, the forecaster added.

“There will be more flooding, damage, fatalities and injuries,” Myers said. “We urge all citizens near the path of Harvey to remain vigilant and be prepared to take immediate action if flood waters rise.”

Partial service has resumed at Houston airports and the port is expected to open for limited business today.

Other transit networks may take longer as roads and other land remains submerged.

British Airways flights between London and Houston remained cancelled today, with the airline hoping to resume operations with one of two daily return services at the weekend.

“As a result of the severe flooding caused by Hurricane Harvey, George Bush intercontinental airport in Houston is currently not able to operate at its normal capacity,” BA said.

“We have cancelled our services to and from Houston up to and including Friday 1 September.

“We are also keeping other services this coming weekend under review, but are planning at this stage to operate one of our normal two daily return services.

“This decision is dependent on the latest information from the airport authorities and the emergency services dealing with the flooding.”

About 100 flights operated in and out of George Bush intercontinental airport yesterday but only a limited number from the domestic Hobby airport as services gradually resumed.

“The Houston Airports has resumed limited domestic airline passenger service following severe weather caused by Hurricane Harvey. The plan is to begin a phased return to service, with full service expected by this weekend,” a spokesman for the operating company said.