Hurricane Harvey’s rain is all but over in Texas and Louisiana, but the catastrophe it inflicted will continue for weeks. Hundreds of square miles are still underwater, thousands of people remain displaced and new terrors are developing in the wake of the nation’s worst hurricane since Katrina in 2005.

Although the rain is moving northeast toward the Tennessee Valley and the Mid-Atlantic, “life-threatening flooding will continue in and around Houston, Beaumont/Port Arthur, and eastward into Southwest Louisiana for the rest of the week,” the National Weather Service said in a 5 a.m. report.

The National Hurricane Center added: “Do not attempt to travel if you are in a safe place and do not drive into flooded roadways.”

In addition to the ongoing flooding in Texas and Louisiana, the threat of dangerous flash flooding is spreading northeast as the storm tracks away from the Gulf Coast. Three to six inches of rainfall are expected from Southwest Louisiana to Kentucky through Friday alone. Local totals up to 10 inches are possible.

Given this storm’s history to produce incredible amounts of rain, residents in northern Louisiana, Tennessee and Kentucky should prepare for flash flooding. Importantly — if there is water on the road, or if it is raining heavily, do not get in your car if you’re already in a safe location. The vast majority of flash flood deaths occur in cars.

As thunderstorms bubble up on the northeast side of Harvey’s circulation, tornadoes will be possible in parts of northern Mississippi, Alabama and Tennessee. A tornado watch is in effect for the region until 8 p.m. Central Time. Tornadoes have already been detected in some storms, and the National Weather Service is issuing warnings as those storms develop.

In a rare message, the National Hurricane Center thanked its partners in its last advisory on the storm:

The National Hurricane Center would like to thank all the men and women that have worked countless hours at local National Weather Service Forecast offices along the Gulf Coast providing lifesaving warnings and information during the past week, on top of preparing their family and homes for the storm. The center would also like to acknowledge the dedication of the Air Force and NOAA Hurricane Hunter aircraft crews that flew numerous missions into Harvey. In addition, NHC thanks the staff at the Weather Prediction Center, who led efforts to coordinate forecasts of the historic flooding event, NWS River Forecast Centers that provided flood guidance, and the Storm Prediction Center, that coordinated tornado forecasts.