GALVESTON, Texas — Hurricane Laura strengthened Wednesday into “an extremely dangerous Category 4 hurricane,” The National Hurricane Center said.

Laura is expected to strike Wednesday night into Thursday morning along the Louisiana-Texas border. Forecasters warn of “catastrophic storm surge, extreme winds and flash flooding” and 20 feet of storm surge.

Louisiana Governor John Bel Edwards is urging southwest residents to flee their homes. In a press conference today, Edwards implored residents to seek safety as Hurricane Laura is expected to bring an unheard-of level of storm surge to Cameron Parish.

Tropical storm winds Wednesday afternoon reached the coast of Louisiana where water levels started to rise. An observing site at Eugene Island measured sustained winds of 39 mph and a gust of 64 mph.

Laura’s well-formed eye was 200 miles south southeast of Lake Charles, Louisiana and Port Arthur, Texas, early Wednesday afternoon.

Laura is predicted to reach at least 145 mph winds, but may weaken ever so slightly before landfall.