Expect heavy traffic and disruption of cellphone service for the total solar eclipse, Charleston public safety officials said Thursday.

Accommodations are 95 percent full for the Aug. 21 eclipse, but it's still unknown how many people will be here from out of town.

"We expect traffic to be a major problem after the event," said Maj. Eric Watson of the Charleston County Sheriff's Office.

In Charleston, the total eclipse is from 2:46 p.m. to 2:48 p.m., but the partial eclipse starts at 1:17 p.m. and ends at 4:10 p.m., according to the National Weather Service.

Watson and other public safety officials who spoke at a press conference Thursday said it's important to stay hydrated and wear ISO-certified eclipse glasses to prevent eye damage. Sunglasses will not provide enough protection. Detailed safety information and a link to reputable vendors can be found on nasa.gov.

Heavy demand will affect cellphone reliability during the eclipse. Do not call 911 to report a cellphone outage, officials said.

"This is the first total eclipse throughout the USA in the cellular era," said Bill Tunick, director of county telecommunications. "You can expect congestion on the cellphone networks and very slow responses."

Text messaging may be a better way to communicate because wireless networks will be clogged with streaming video and social media activity.

"Please know that it's not your phone that is causing the problem," Tunick said. "It's the network being congested," Tunick said.

Jim Lake, director of the county 911 center, said to be patient and stay on the line if a 911 call is not answered immediately. Text messages may be sent to 911, he said.

Don't stop in traffic on roads or bridges to watch the eclipse. Citations will be issued. Cars parked on bridges will be towed. The pedestrian walkway on the Arthur Ravenel Jr. Bridge will be closed because emergency officials worry about response times in a big crowd, officials said.

Charleston officials recommended enjoying the eclipse at a park, such as Marion Square, which will have cooling tents and water. The city will have 28 parks and recreation centers staffed for the event.

The Sheriff's Office will increase patrols, mainly in the McClellanville, Awendaw and Edisto Island areas. The marine patrol will be activated to monitor the waterways and Charleston Harbor. Traffic will be monitored from the air, Watson said.

"We're not trying to take away the excitement of the event," Watson said. "We're also going to enjoy it ourselves but make sure that those who live here and come here can enjoy it in a safe environment."

Reach Prentiss Findlay at 843-937-5711.