Hurricane Alex killed four people in two separate incidents in Monterrey, the capital city of the northern Mexican state Nuevo Leon, civil protection authorities said Wednesday.

People remove the roof of a beach shelter before hurricane Alex is expected to make landfall, at Miramar beach in Tampico June 30, 2010. Hurricane Alex moved slowly in Gulf waters on Wednesday, growing stronger and likely to come ashore later in the day but sparing Mexican oil rigs and U.S. oil fields to the relief of crude markets. [Xinhua]

Hurricane Alex, which is now category two and has a radius of 110 km, has already killed 11 people across Central America and southern Mexico. Moreover, it has caused floods across southern Mexico. It has steady winds of 155 km per hour (kph) and gusts of up to 185 kph.

The U.S. National Hurricane Center (NHC) said the storm has made its landfall in northern Mexico Wednesday night.

Hurricane warnings have been dropped for the South Texas coast, according to local officials, and downgraded to tropical storm warnings.

However, forecasters said rainbands and squalls from Alex will continue along the Gulf coast from the U.S. state of Louisiana through Texas.

They said the biggest concern regarding Alex for the United States is heavy rain that brings potential flooding. Widespread rainfall totaling four inches or more is likely for southern Louisiana and southwestward across much of south and southeast Texas.

The agency predicted the storm will dissipate over land within 48 hours and rains associated with the storm "could cause life-threatening flash floods and mud slides."

It also warned of a storm surge, a tsunami of up to six feet that follows the hurricane's eye, which could reach several miles inland.

Earlier in the day, authorities in Tamaulipas state said they had closed all schools statewide. Nuevo Leon authorities issued the same order just hours later.