CONCORD -- Four people have been transported to local hospitals from the Concord Pavilion because of heat-related issues this afternoon, while a handful of others are being treated at the site, fire officials said.

There are currently two Contra Costa fire engines and five ambulances at the outdoor venue, and the number of cases may increase, Capt. Robert Marshall said.

Sunday's performance by Gladys Knight started at noon.

Marshall pointed out that when the weather is in the low- to mid-90s -- such as Sunday and expected Monday -- there tend to be more cases of heat exhaustion.

"The biggest thing is that people should try to stay in the shade and stay hydrated," he said.

When the temperature hits triple digits, people tend to have more of a psychological reaction and realization that need to stay hydrated, he said.

For updates, check back to ContraCostaTimes.com.

Contact Paul Burgarino at 925-779-7164. Follow him at Twitter.com/paulburgarino.