Hurricane Harvey is now the second most destructive storm in U.S. history, behind only Hurricane Katrina. The devastation is massive: 46 dead and an estimated $80 billion in damage — so far.

Harvey could end up being the most expensive of all. It depends on what happens in the coming weeks. The longer homes stay flooded and businesses remain closed, especially the major oil refineries that supply a substantial amount of the country's gasoline, the bigger the hit to Texas and the entire U.S. economy.

Gas prices are at the highest level in two years after Harvey shut down 20 percent of U.S. refining capacity. Americans across the country are seeing a hit to their wallets from the added costs, and the country might not be able to export oil for a while.

“This was a worst case situation,” says Chuck Watson, head of Enki Research, a company that forecasts natural disasters. His latest estimate is an $80 billion price tag for Harvey, double his initial prediction. The vast majority of that bill will be paid by taxpayers, since private insurance rarely covers flooding.

It's too early to know the final toll. Current estimates differ widely, from $50 billion $190 billion. Watson says Harvey is “breaking all the models” because of the extensive flooding, which makes it hard to get a decisive read on the devastation. Katrina caused more than 1,800 deaths and $125 billion in damage when it hit the Gulf Coast in 2005. In today's dollars, that equates to $160 billion, according to government calculations.

“This is clearly one of the bigger ones, if not the biggest in terms of damages,” says Michael Gapen, head of U.S. economic research at Barclays. “It could have a significant impact on growth, at least in the third quarter.”

If it ends up being similar to Katrina in terms of the cost and duration of the recovery, there will be a rapid hit to jobs and growth. Hundreds of thousands of people are likely to be out of work for days, if not weeks, and economic growth could be 1 percent lower in the third quarter, the period from July through September. That's a substantial decline, considering that the U.S. grew only by an annual rate of 3 percent in the spring. But the pain could be short-lived if the government steps in with a lot of aid.

“The lesson from both Katrina and Sandy is that the quicker government aid and insurance money gets to a ravaged area, the smaller the economic blow,” said Mark Zandi, chief economist at Moody's Analytics.

President Trump was expected to ask Congress to quickly provide $6 billion, but that's a small fraction of the total bill. Some federal aid is already flowing to Texas from existing funds managed by the Federal Emergency Management Agency and the Small Business Administration. FEMA given out more than $35 million so far.

Houston is America's fourth-largest city and the hub of the country's petroleum industry. About 100,000 homes are damaged, White House homeland security adviser Tom Bossert said Thursday. He predicted a “long, frustrating recovery.”

Vice President Pence was more upbeat. In Rockport on Thursday, he vowed that Texas would come back “bigger and better than ever before.”

Economists surveyed by The Washington Post are also optimistic that the greater Houston area will rebound much faster than New Orleans did.

“Strong, vibrant economies recover,” says Kurt Karl, chief economist at insurance company Swiss Re. Unlike New Orleans, Houston had been growing rapidly before the storm hit. Oil is the heart of the region's economy, but Houston has diversified in recent years with more jobs in health care, tourism and tech.

A key sign to watch is whether people flee Houston. New Orleans suffered a massive population exodus, causing the city to lose half of its people in the year following the storm. That means fewer workers, lower tax receipts and less spending in stores and restaurants.

“In Houston, people have not left. They are in shelters, but they aren't gone. Sooner or later, they will rebuild,” predicts Rajeev Dhawan, director of Georgia State University's Economic Forecasting Center.

Once the reconstruction efforts get underway, it usually causes an economic boom that balances out — or even overcompensates — the losses. This will be a major opportunity for anyone involved in the construction industry. Contractors were already complaining they couldn't find enough skilled workers. The dire need for builders may lure more workers to Houston, especially if wages spike since there's so much demand that people are willing to pay more. Some argue immigrant labor from Mexico could also help speed up the rebuilding process.

It will also be a boon for stores and car manufacturers as people replace what they lost. The stocks of Ford and General Motors jumped this week as it became clear that tens of thousands of cars are damaged from the storm. Texans will likely be buying new vehicles soon.

“It feels wrong to think about it like this, but historically, these storms just cause temporary disturbances to the economy,” says Gapen. He expected a rebound by the fourth quarter.

Taxpayers will end up funding most of the rebuilding because traditional insurance doesn't cover flooding. Business executives and homeowners have to go out and buy special flood insurance policies. More than 80 percent of homeowners in the areas hardest hit in southeast Texas didn't do that. Flood insurance is only required for property owners in places that FEMA designates as extremely high risk. About two-thirds of the homes hit by Harvey weren't in those zones, Watson says.

The National Flood Insurance Program, a government-run program, is the only place that offers U.S. homeowners flood insurance. NFIP will end up covering $9 billion, according to CoreLogic, a company that tracks losses. Private insurers only cover flooding damage to businesses, and even that is limited. Private insurers will pay around $2 billion, predicts AIR Worldwide, another catastrophe-modeling firm.

To put it another way, insurance of any sort will cover less than 15 percent of Harvey's $80 billion tab. Charity and people's savings will help a little, but the bulk of the humanitarian and rebuilding costs will come from government.

All the signs indicate Texas is likely to recover and the U.S. economy probably won't see much lingering impact, but economists warn some families won't be as lucky.

“There are individuals, households and businesses within these communities who can never recover,” says Matthew Fienup, director of the Center for Economic Research at California Lutheran University. “These should be the primary targets of the long-term policy response to this disaster.”