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USA TODAY

Hurricane Harvey, pumped up by warm waters of the Gulf of Mexico, made landfall Friday night on the Texas coast near Rockport. It is expected to be the strongest storm to hit the United States in more than a decade.

Here's what we know now:

Harvey hits Texas

Hurricane Harvey made landfall at 10 p.m. CDT as a Category 4 storm in Texas late Friday, bringing with it 130-mph winds and unleashing flash floods, storm surges and up to three feet of rain.

Harvey is the first major hurricane — classified as Category 3 or above — to hit the USA since Hurricane Wilma in 2005.

The National Weather Service said the storm intensified to a Category 4 hurricane Friday afternoon. Harvey could dump up to three feet of rain in some spots in the next week as it lingers over the area, adding to the threat of flash flooding and storm surges.

Some forecasts are calling for as much as a mind-boggling 60 inches (that's five feet) of rain from Harvey.

Late Friday night, FEMA announced that federal disaster assistance was made available for the state of Texas to supplement recovery efforts in affected storm areas.

More:Amid Hurricane Harvey threat, decision to order evacuation can be a difficult one

More:Hurricane Harvey: 'Flooding disaster' possible as storm stalls over Texas

What is the storm's biggest threat?

While a 4-6 foot storm surge and howling, 100 mph or higher winds will be a deadly threat, the storm's biggest concern may eventually turn out to be flooding from days and days of torrential rain. Harvey will stall and spin for the next three to five days, dumping up to 2 feet of rain across the region. Harvey "may be nothing short of a flooding disaster," for Texas, according to AccuWeather meteorologist Alex Sosnowski, who said some communities could be underwater for days. Forecasters were already measuring 28-foot-high waves near the eye of the storm.

Record- breaking storm

Since Harvey hit Texas as a Category 4 hurricane, it is the strongest storm to hit the U.S. in 12 years. The last such system was Hurricane Wilma in Florida in October 2005.

Harvey is also the strongest to strike Texas since 1961’s Hurricane Carla, the most powerful Texas hurricane on record.

In advance of the storm, Texas Gov. Greg Abbott declared a state of disaster for 30 counties. Almost 233,000 homes on the Texas coast are at risk, with a potential reconstruction bill of almost $40 billion, according to CoreLogic, a company that conducts global property analysis.

Early Saturday morning, President Trump said on Twitter his office would "remain fully engaged w/ open lines of communication." Trump also tweeted that he was in contact with the governors of Texas and Louisiana. "I have spoken w/ @GovAbbot of Texas and @LouisianaGov Edwards. Closely monitoring #HurricaneHarvey developments & here to assist as needed," Trump's tweet read.

Gov. Abbott said the president and other federal authorities assured him Texas will get any help needed. “All of them provided strong, unequivocal assurances (that the federal government) will help the state of Texas in any way,” Abbott said.

Airlines waive change fees

Most big U.S. airlines enacted flexible rebooking policies for fliers ticketed to fly to the region. The policies vary by airline, but generally permit eligible customers to make one change to their itineraries without paying change fees that can cost $200 or more per passenger. The policies also typically allow fliers to move their flights without paying a fare difference, though there’s usually a finite travel window to do so. For passengers wishing to move their flights to dates outside beyond those booking windows, most carriers will allow customers to apply the full value of their remaining ticket toward a newly booked one. As always, customers should check with their specific airline for the exact details.

Gas prices might rise

With Harvey barreling toward the energy-rich Texas Gulf Coast, gasoline prices could tick upward at the end of the summer driving season as refineries shut down capacity to brace for impact. Experts are expecting anywhere from a 5-cent to 15-cent increase in the price of a gallon of gasoline over the next week as Harvey forces refineries in its path to take precautionary measures to prevent damages. The storm would have to get much more severe than its current classification as a Category 3 hurricane to do much damage to gasoline refineries, analysts said.

Mandatory evacuations

All seven Texas counties on the coast from the Corpus Christi area to the western end of Galveston Island have ordered the mandatory evacuations for tens of thousands of residents from all low-lying areas. About 700,000 people live in areas under the hurricane warning, roughly half of them in the Corpus Christi area.

Voluntary evacuations

Voluntary evacuations have been urged for the city Corpus Christi and for the Bolivar Peninsula, where many homes were washed away by the storm surge of Hurricane Ike in 2008.

What are universities doing?

Many Texas universities are closing in preparation of the story. The University of Houston will close its main and satellite campuses Friday, Saturday and Sunday. Texas A&M University delayed move in for students on it's Corpus Christi campus and closed it's Galveston campus at noon Friday. Rice University and Texas State University followed suit, closing Friday. Things will continue as scheduled, though, at Texas Southern University in Houston.

Contributing: The Associated Press