A tropical depression strengthened into a tropical storm Saturday off the Carolinas — the latest wild weather expected to hit the nation over the long holiday weekend as a fourth person was found dead amid flooding in Texas.

Tropical Storm Bonnie formed just before 5 p.m. ET and was about 130 miles southeast of Beaufort, South Carolina and packing maximum sustained winds of 45 mph winds as of 11 p.m., the National Hurricane Center said. It was forecast to drench the Carolinas with up to three inches of rain, which had already started falling on the South Carolina coast earlier Saturday.

Whipping winds and dangerous waves as high as 13 feet could also hit the two states, as well as Georgia and Florida over the coming days, forecasters said.

As of Saturday evening, no evacuations were ordered. Charleston police warned drivers to be wary of downed trees and power lines, and to not drive through flooded areas. A little more than 1 1/2 inches of rain was recorded at Charleston Air Force Base by Saturday evening, according to the National Weather Service.

A depression becomes a tropical storm when winds reach 39 mph. Forecasters detected winds at 40 mph, making Bonnie the season’s second-named tropical storm, four days before the official start of the Atlantic hurricane season.

Elsewhere in the nation, flooding and heavy rain were wreaking havoc. In Texas, at least four people were killed and two others were missing after torrential downpours, and the state was bracing for more rain through Memorial Day.

Lela Holland, 64, died in her home when floods washed through, according to the Washington County Sheriff’s office. Jimmy Wayne Schaeffer, 49, was killed when he drove his truck into high water, a statement from the office said.

The body of Darren Mitchell, 21, a National Guardsman, was recovered Saturday after his vehicle was swept off the road by floods, the statement said. And Pyarali Rajebhi Umatiya, 59, was killed when his vehicle stalled in high water, according to the statement.

Related: Two Dead in Texas As Plains Gear Up for More Bad Weather

The county, a rural area between Austin and Houston, saw nearly two feet of rain in a span of just a few hours Friday, according to officials.

Several bridges were damaged, 58 roads were still closed Saturday and 2,000 residents remained without electricity, the sheriff’s office said.

Meanwhile, Travis County officials were searching for two residents who were swept away by the raging waters. Multiple people were rescued from rooftops by helicopters, Travis County Emergency Services tweeted Friday.

In Kansas, an 11-year-old boy fell into the fast-moving Gypsum Creek in Wichita and was swept away as friends tried to grab him, NBC affiliate KSNW reported. The creek was swollen by recent rains. On Saturday, fire officials said the search was now a recovery operation, but Wichita Fire Department Battalion Chief Scott Brown told the station the search would continue. “We’ll go until we can’t go any more,” he said.



In Tyler County, Texas, a mandatory evacuation was in place for the 30 to 40 homes in the Barlow Lake Estates subdivision, where rising crests could likely force the Corps of Engineers to release water from a local dam in the coming days, said county emergency management officials.

The resulting downstream flooding could be of historic proportions, county officials posted on Facebook.

In Missouri, Gov. Jay Nixon declared a state of emergency ahead of expected heavy rains Saturday, and warned that levees could be breached.

Related: Two Dead in Texas As Plains Gear Up for More Bad Weather

“Areas along the Missouri River and its tributaries in west-central Missouri are of particular concern because more rain could cause some levees to overtop,” Nixon said in a statement issued Friday night.

Since Tuesday, storms in the state have caused high winds, heavy rains and flash flooding — with more rain predicted into the weekend.

“State emergency management personnel will continue to work with local officials and law enforcement to assess and closely monitor the risk to the levees, and take appropriate action if needed,” Nixon said.

The torrential downpour was part of severe weather that pummeled the nation’s midsection Thursday night, with tornadoes reported in Kansas and Texas.